【Java Web 程序开发】学习笔记

作者: Du1in9 | 来源:发表于2020-05-13 11:30 被阅读0次

参考文献：https://book.douban.com/subject/26581849/
完整源代码：https://pan.baidu.com/s/1IQUsLuFwOj_QXglHPPmqug 提取码：2647

第一章 XML基础
1.1 XML概述
1.1.1 W3C组织介绍
https://wiki.hk.xileso.top/wiki/W3C
1.1.2 什么是XML
https://baike.baidu.com/item/%E5%8F%AF%E6%89%A9%E5%B1%95%E6%A0%87%E8%AE%B0%E8%AF%AD%E8%A8%80/2885849?fromtitle=xml&fromid=86251&fr=aladdin
1.1.3 XML与HTML的比较
https://blog.csdn.net/m18633778874/article/details/79028240/
1.2 XML语法
例1-1 元素定义，注释
book.xml

<?xml version="1.0" encoding="GB2312"?>
<!--注释信息-->
<书架>
    <书>
        <书名>程序员的自我修养</书名>
        <价格>23.5元</价格>
    </书>
    <书>
        <书名>肖生克的救赎</书名>
        <价格>20.5</价格>
    </书>
</书架>

建议用notepad++编写，浏览器打开

例1-2 特殊字符

<书名>&lt;程序员的自我修养&gt;</书名>

例1-3 CDATA区
java.xml

<?xml version="1.0"?>
<java>
<![CDATA[
    if(a>b&&b>c)
        max=a;
]]>
</java>

1.3 DTD约束
例1-4 DTD约束
Note.xml

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE note SYSTEM "Note.dtd">
<note>
<to>George</to>
<from>John</from>
<heading>Reminder</heading>
<body>Don't forget the meeting!</body>
</note>

Note.dtd

<?xml version="1.0" encoding="GB2312"?>
<!ELEMENT note (to, from, heading, body)>
<!ELEMENT to (#PCDATA)>
<!ELEMENT from (#PCDATA)>
<!ELEMENT heading (#PCDATA)>
<!ELEMENT body (#PCDATA)>

1.4 Schema 约束
例1-5 使用名称空间引入XML Schema文档
book1.xml

<?xml version="1.0" encoding="UTF-8"?>
<书架 xmlns="http://www.it315.org/xmlbook/schema"
xmlns:demo="http://www.it315.org/demo/schema"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.it315.org/xmlbook/schema http://www.it315.org/xmlbook.xsd
http://www.it315.org/demo/schema http://www.it315.org/demo.xsd">

<书>
<书名>JavaScript网页开发</书名>
<作者>木丁西</作者>
<售价 demo:币种=”人民币”>28.00元</售价>
</书>
</书架>

例1-6 不使用名称空间引入XML Schema文档
book2.xml

<?xml version="1.0" encoding="UTF-8"?>
<书架 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:noNamespaceSchemaLocation="xmlbook.xsd">
<书>
<书名>JavaScript网页开发</书名>
<作者>张孝祥</作者>
<售价>28.00元</售价>
</书>
</书架>

第二章 Tomcat 开发Web站点
2.1 Web开发相关知识
2.1.1 B/S架构和C/S架构
https://blog.csdn.net/sea_snow/article/details/81187804
2.1.2 通信协议
https://www.cnblogs.com/xhwy/archive/2012/03/03/2378293.html
2.1.3 Web资源
https://www.cnblogs.com/linkworld/p/7573043.html
例2-1 dynamic.html

现在的时间是：
<script type="text/javascript">
document.write(new Date());
</script>

2.2 安装Tomcat
2.2.1 Tomcat简介
https://baike.baidu.com/item/tomcat/255751?fr=aladdin
2.2.2 Tomcat安装和启动
个人不建议配置tomcat8，后面用Myclipse做项目不方便
https://blog.csdn.net/oqqKen12345/article/details/82839914
例2-2 dynamic.jsp

Now the time is:<br>
<%=new java.util.Date()%>

（运行Tomcat，jsp文件放在Apache-Tomcat-8.5.45\webapps\Me\文件夹，再访问http://localhost:8080/Me/dynamic.jsp即可）
2.3 发布Web应用
2.3.1 什么是Web应用
https://www.jianshu.com/p/ddbe852179fe
2.3.2 配置Web应用虚拟目录（选做）
https://blog.csdn.net/baolibin528/article/details/38034101
2.3.3 配置Web应用默认页面（选做）
https://blog.csdn.net/weixin_43740680/article/details/92086233
2.3.4 Tomcat的管理平台
https://blog.csdn.net/cuijiying/article/details/78526982

2.4 Eclipse中配置Tomcat服务器
https://jingyan.baidu.com/article/219f4bf7b57b20de442d38ac.html
第三章 HTTP协议
3.1 HTTP概述
3.1.1 HTTP介绍
https://www.runoob.com/http/http-intro.html
3.1.2 HTTP1.0和HTTP1.1
https://blog.csdn.net/FU250/article/details/90763223
3.1.3 HTTP消息
https://blog.csdn.net/huangjin0507/article/details/52170460
3.2 HTTP请求信息
https://blog.csdn.net/u010256388/article/details/68491509/
例3-1 GET.html

<html>
<body>
<form action="" method="get">
    姓名：<input type="text" name="name" style="width:150px"/><p/>
    年龄：<input type="text" name="age" style="width:150px"/><p/>
    <input type="submit" value="提交"/><p/>
</form>
</body>
</html>

例3-2 POST.html

<html>
<body>
<form action="" method="post">
    姓名：<input type="text" name="name" style="width:150px"/><p/>
    年龄：<input type="text" name="age" style="width:150px"/><p/>
    <input type="submit" value="提交"/><p/>
</form>
</body>
</html>

中文乱码咋办？如图：

打开Tomcat，访问http://localhost:8080/Three/GET.html，输入Jack，40，再看请求头消息

打开Tomcat，访问http://localhost:8080/Three/POST.html，输入Jack，40，再看请求头消息

3.3 HTTP响应信息
3.3.1 HTTP响应状态行
https://blog.csdn.net/zjs_csdns/article/details/89004295?utm_medium=distribute.pc_relevant.none-task-blog-BlogCommendFromMachineLearnPai2-1.nonecase&depth_1-utm_source=distribute.pc_relevant.none-task-blog-BlogCommendFromMachineLearnPai2-1.nonecase
3.3.2 HTTP响应消息头
https://www.runoob.com/http/http-header-fields.html
3.4 HTTP其他头字段
3.4.1 通用头字段
https://blog.csdn.net/u010369338/article/details/69566058/
3.4.2 实体头字段
https://www.iteye.com/blog/zengguo1988-283702
第四章 Servlet技术
4.1 Servlet开发入门
4.1.1 Servlet接口
https://www.cnblogs.com/weibanggang/p/9464307.html
4.1.2 实现第一个Servlet程序
先找到servlet-api.jar，设置环境变量

set classpath=%classpath%;E:\apache-tomcat-8.5.45\apache-tomcat-8.5.45\lib\servlet-api.jar

例4-1 HelloWorldServlet.java

package Java_Web.Four;//这是包名，也就是文件夹的路径，我这里是E:\Java_Web\Four
import java.io.*;
import javax.servlet.*;

public class HelloWorldServlet extends GenericServlet{
  public void service(ServletRequest request,ServletResponse response) throws ServletException,IOException{
    PrintWriter out = response.getWriter();
    out.println("XXXXX");
  }
}

编译

javac HelloWorldServlet.java

在webapps文件夹新建xxx\WEB-INF\classes目录，然后将包放进去

在WEB-INF中，新建web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
                     http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
  version="3.0">
 <servlet>
       <servlet-name>HelloWorldServlet</servlet-name>
       <servlet-class>Java_Web.Four.HelloWorldServlet</servlet-class>
    </servlet>
 <servlet-mapping>
       <servlet-name>HelloWorldServlet</servlet-name>
        <url-pattern>/HelloWorldServlet</url-pattern>
    </servlet-mapping>
</web-app>
<!--
<servlet>用于注册Servlet
<servlet-name>HelloWorldServlet</servlet-name>指定servlet的名称为HelloWorldServlet，你也可以改成其他的
<servlet-class>java_web.HelloWorldServlet</servlet-class>指定servlet完整的类名，要和你编写的.java 文件的类名相同
<servlet-mapping>用于映射servlet对外访问虚拟路径，它的<servlet-name>名字必须和<servlet>中的<servlet-name>相同
<url-pattern>是指定该servlet的虚拟路径,该路径以正斜杠(/)开头，表示当前web应用程序的根目录
-->

启动Tomcat，访问http://localhost:8080/Four/HelloWorldServlet即可

①如果出现以下情况，多半是web.xml书写格式有误，一点点失误就会报错，巨坑

②因为每次编译都要设置环境变量比较麻烦，可以把语句存在一个文本里，下次直接套用，例如我的就是：

cd /d E:\apache-tomcat-8.5.45\apache-tomcat-8.5.45\webapps\chapter04\WEB-INF\classes\Java_Web\Four
set classpath=%classpath%;E:\apache-tomcat-8.5.45\apache-tomcat-8.5.45\lib\servlet-api.jar
javac xxx.java

4.1.3 Servlet的生命周期
https://www.runoob.com/servlet/servlet-life-cycle.html
4.2 Servlet高级应用
4.2.1 HttpServlet
例4-3
RequestMethodServlet.java

package Java_Web.Four;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class RequestMethodServlet extends HttpServlet{
  public void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException{
    PrintWriter out = response.getWriter();
    out.println("this is doGetmethod");
  }
  public void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException{
    PrintWriter out = response.getWriter();
    out.println("this is doPostmethod");
  }
}

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
                     http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
  version="3.0">
 <servlet>
       <servlet-name>RequestMethodServlet</servlet-name>
       <servlet-class>Java_Web.Four.RequestMethodServlet</servlet-class>
    </servlet>
 <servlet-mapping>
       <servlet-name>RequestMethodServlet</servlet-name>
        <url-pattern>/RequestMethodServlet</url-pattern>
    </servlet-mapping>
</web-app>

开启tomcat，访问http://localhost:8080/chapter04/RequestMethodServlet

在webapp\chapter04目录下新建form.html

<form action="/chapter04/RequestMethodServlet" method="post">
    姓名：<input type="text" name="name" style="width:150px"/><p/>
    密码：<input type="text" name="psw" style="width:150px"/><p/>
    <input type="submit" value="提交"/><p/>
</form>

访问http://localhost:8080/chapter04/form.html

点击提交，会显示“this is doPostmethod”，所以我们知道采用POST方式请求Servlet时，会自动调用doPost( )方法
4.2.2 使用MyEclipse开发Servlet
新建Web项目

新建Servlet程序

对Servlet的doPost( )和doGet( )方法进行修改

如果servers窗口不见了，点击windows--show views--others

直接在Myclipse里运行

4.2.3 Servlet虚拟路径的映射
https://blog.csdn.net/qq_24042659/article/details/82967306
4.3 ServletConfig和ServletContext
4.3.1 ServletConfig接口

Servlet运行期间，通常需要一些辅助信息，可以在web.xml中使用<init-param>进行配置
<param-name>表示参数名称，<param-value>表示参数值

新建Servlet程序，配置web.xml

<servlet>
    <display-name>TestServlet02</display-name>
    <servlet-name>TestServlet02</servlet-name>
    <servlet-class>Java_Web.Four.TestServlet02</servlet-class>
    <init-param>
      <param-name> encoding </param-name>
      <param-value> UTF-8 </param-value>
    </init-param>
</servlet>

TestServlet02.java

package Java_Web.Four;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class TestServlet02 extends HttpServlet{
  public void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException{
    PrintWriter out = response.getWriter();
    ServletConfig config=this.getServletConfig();
    String param=config.getInitParameter("encoding");
    out.println("encoding="+param);
  }
  public void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException{
      this.doGet(request,response);
  }
}

编译，运行，访问

可以看出，ServletConfig对象可以获得web.xml中的参数信息
4.3.2 ServletContext接口
①获取初始化参数
例4-6
web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
                     http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
  version="3.0">
  
  <servlet>
    <display-name>TestServlet03</display-name>
    <servlet-name>TestServlet03</servlet-name>
    <servlet-class>Java_Web.Four.TestServlet03</servlet-class>
  </servlet>
  <context-param>
    <param-name> companyName </param-name>
    <param-value> alibaba </param-value>
  </context-param>
  <context-param>
    <param-name> address </param-name>
    <param-value> earth </param-value>
  </context-param>
  <servlet-mapping>
    <servlet-name>TestServlet03</servlet-name>
    <url-pattern>/TestServlet03</url-pattern>
  </servlet-mapping>
</web-app>

TestServlet03.java

package Java_Web.Four;
import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class TestServlet03 extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
          PrintWriter out = response.getWriter();
          // 得到ServletContext对象
         ServletContext context = this.getServletContext();
         // 得到包含所有初始化参数名的Enumeration对象
         Enumeration<String> paramNames = context.getInitParameterNames();
          // 遍历所有的初始化参数名，得到相应的参数值，打印到控制台
         out.println("all the paramName and paramValue are following:"+"<br>");
          // 遍历所有的初始化参数名，得到相应的参数值并打印
         while (paramNames.hasMoreElements()) {
            String name = paramNames.nextElement();
            String value = context.getInitParameter(name);
            out.println(name + ": " + value);
              out.println("<br>");
         }
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
          this.doGet(request, response);
    }
}

编译，运行，访问

②实现共享数据
例4-7
TestServlet04.java

package Java_Web.Four;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class TestServlet04 extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        ServletContext context = this.getServletContext();
         // 通过setAttribute()方法设置属性值
        context.setAttribute("data", "this servlet save data");
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doGet(request, response);
    }
}

例4-8
TestServlet05.java

package Java_Web.Four;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class TestServlet05 extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
     PrintWriter out = response.getWriter();
        ServletContext context = this.getServletContext();
                // 通过getAttribute()方法获取属性值
        String data = (String) context.getAttribute("data");
        out.println(data);
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doGet(request, response);
    }
}

编译，启动，分别访问，可知ServletContext存储数据可被多个Servlet共享
③读取Web应用资源文件
在classes目录下新建资源文件itcast.properties

Company=abcdefg
Address=earth

例4-9
TestServlet06.java

package Java_Web.Four;
import java.io.*;
import java.util.Properties;
import javax.servlet.*;
import javax.servlet.http.*;
public class TestServlet06 extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        ServletContext context = this.getServletContext();
        PrintWriter out = response.getWriter();
        InputStream in = context
                .getResourceAsStream("/WEB-INF/classes/itcast.properties");
        Properties pros = new Properties();
        pros.load(in);
        out.println("Company=" + pros.getProperty("Company") + "<br>");
        out.println("Address=" + pros.getProperty("Address") + "<br>"); 
}
    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doGet(request, response);
    }
}

第五章请求和响应
5.1 HttpServletResponse对象
5.1.1 发送状态码
5.1.2 发送响应消息头
5.1.3 发送响应消息体
①getOutputStream()方法
②getWriter()方法
例5-1
PrintServlet.java

package Java_Web.Five;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class PrintServlet extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String data="hello_motherfucker!";
        OutputStream out=response.getOutputStream();// 获取输出流对象
        out.write(data.getBytes());                     // 输出字符串信息
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request,response);
    }
}

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
                     http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
  version="3.0">
  <servlet>
    <display-name>PrintServlet</display-name>
    <servlet-name>PrintServlet</servlet-name>
    <servlet-class>Java_Web.Five.PrintServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>PrintServlet</servlet-name>
    <url-pattern>/PrintServlet</url-pattern>
  </servlet-mapping>
</web-app>

5.2 HttpServletResponse应用
5.2.1 中文输出乱码问题
法一：例5-3
ChineseServlet.java

package Java_Web.Five;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class ChineseServlet extends HttpServlet {
    public void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {
        response.setCharacterEncoding("utf-8");//设置字符编码方式
        String data="中国";
        PrintWriter out = response.getWriter();   
        out.println(data);
    }
    public void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {
        doGet(request,response);
    }
}

修改浏览器编码：https://jingyan.baidu.com/article/cd4c2979f2a664756e6e60db.html

法二：例5-4
ChineseServlet.java

package Java_Web.Five;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class ChineseServlet extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String data="中国";
         response.setContentType("text/html;charset=utf-8");//设置HttpServletResponse和浏览器编码为utf-8
        PrintWriter out = response.getWriter();
        out.println(data);
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request,response);
    }
}

5.2.2 网页定时刷新并跳转
例5-5
RefreshServlet.java

package Java_Web.Five; 
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class RefreshServlet extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
         // 2秒后刷新并跳转到指定网页
         response.setHeader("Refresh","2;URL=https://www.jianshu.com/u/32aab16373de");
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        doGet(request, response);
    }
}

例5-6
RefreshServlet.java

package Java_Web.Five; 
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class RefreshServlet extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {      
        response.setHeader("Refresh","1");// 每隔1秒定时刷新当前页面
        response.getWriter().println(new java.util.Date());// 输出当前时间
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        doGet(request, response);
    }
}

5.2.3 禁止浏览器缓存页面
例5-7
CacheServlet.java

package Java_Web.Five; 
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class CacheServlet extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        response.setContentType("text/html;charset=utf-8"); 
        response.setDateHeader("Expires",0);
        response.setHeader("Cache-Control","no-cache"); 
        response.setHeader("Pragma","no-cache");  
        PrintWriter out = response.getWriter();
        out.println("本次响应的随机数为：" + Math.random());
        out.println("<form action='NotServlet'" + "method='POST'>" +
            "第一个参数：<input type='text' name='p1'><br>" +
            "第二个参数：<textarea name='p2'></textarea><br>" +
            "<input type='submit' value='提交'> " +
            "</form>");
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        doGet(request, response);
    }
}

5.2.4 请求重定向
例5-8
login.html

<!--把表单内容提交到chapter05工程下的LoginServlet-->
<form action="/chapter05/LoginServlet" method="post">
    用户名： <input type="text" name="username" /><br> 
    密  码： <input type="password" name="password" /><br> 
    <input type="submit" value="登录" />
</form>

welcome.html

<html>
    <head>
        <title>Insert title here</title>
    </head>
    <body>
        欢迎你 ♂ 登录成功！
    </body>
</html>

LoginServlet.java

package Java_Web.Five; 
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class LoginServlet extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        response.setContentType("text/html;charset=utf-8");
        // 用HttpServletRequest对象的getParameter()方法获取用户名和密码
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        // 假设用户名和密码分别为：Du1in9和123
        if (("Du1in9").equals(username) &&("123").equals(password)) {
            response.sendRedirect("/chapter05/welcome.html");// 如果用户名和密码正确，重定向到 welcome.html
        } 
        else {
            response.sendRedirect("/chapter05/login.html");// 如果用户名和密码错误，重定向到login.html
        }
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        doGet(request, response);
    }
}

5.3 HttpServletRequest对象
5.3.1 获取请求行信息
例5-11
RequestLineServlet.java

package Java_Web.Five; 
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class RequestLineServlet extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        response.setContentType("text/html;charset=utf-8");
        PrintWriter out = response.getWriter();
        // 获取请求行的相关信息
        out.println("getMethod : " + request.getMethod() + "<br>");
        out.println("getRequestURI : " + request.getRequestURI() + "<br>");
        out.println("getQueryString : " + request.getQueryString() + "<br>");
        out.println("getProtocol : " + request.getProtocol() + "<br>");
        out.println("getContextPath : " + request.getContextPath() + "<br>");
        out.println("getPathInfo : " + request.getPathInfo() + "<br>");
        out.println("getPathTranslated : " + request.getPathTranslated()+ "<br>");
        out.println("getServletPath : " + request.getServletPath() + "<br>");
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        doGet(request, response);
    }
}

5.3.2 获取请求消息头
例5-12
RequestHeadersServlet.java

package Java_Web.Five; 
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Enumeration;
import javax.servlet.*;
import javax.servlet.http.*;
public class RequestHeadersServlet extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        response.setContentType("text/html;charset=utf-8");
        PrintWriter out = response.getWriter();
        // 获取请求消息中所有头字段
        Enumeration headerNames = request.getHeaderNames();
        // 使用循环遍历所有请求头，并通过getHeader()方法获取一个指定名称的头字段
        while (headerNames.hasMoreElements()) { 
            String headerName = (String) headerNames.nextElement();
            out.print(headerName + " : " + request.getHeader(headerName)+ "<br>");
        }
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        doGet(request, response);
    }
}

利用Referer请求头防止“盗链”
例5-13
download.html

<html>
    <head>
        <title>Insert title here</title>
    </head>
    <body>
        <a href="/chapter05/DownManagerServlet">download</a>
    </body>
</html>

例5-14
DownManagerServlet.java

package Java_Web.Five;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class DownManagerServlet extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        response.setContentType("text/html;charset=utf-8");
        PrintWriter out = response.getWriter();
        String referer = request.getHeader("referer");// 获取referer头的值
        String sitePart = "http://" + request.getServerName();// 获取访问地址
        // 判断referer头是否为空，这个头的首地址是否以sitePart开始的
        if (referer != null && referer.startsWith(sitePart)) {
            out.println("Downloading ...");// 处理正在下载的请求
        } 
        else {// 非法下载请求跳转到download.html页面
            RequestDispatcher rd = request.getRequestDispatcher("/download.html");
            rd.forward(request, response);
        }
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        doGet(request, response);
    }
}

5.3.3 获取请求消息体
例5-15
form.html

<form action="/chapter05/RequestBodyServlet" method="post">
    用户名：<input type="text" name="username"><br>
    密  码：<input type="password" name="password"><br>
    <input type="submit" value="提交">
</form>

RequestBodyServlet.java

package Java_Web.Five;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class RequestBodyServlet extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        response.setContentType("text/html;charset=utf-8");
        
        InputStream in = request.getInputStream();// 获取输入流对象
        byte[] buffer = new byte[1024]; // 定义1024个字节的数组
        StringBuilder sb = new StringBuilder(); // 创建StringBuilder对象
        int len;
        while ((len = in.read(buffer)) != -1) {// 循环读取数组中的数据
            sb.append(new String(buffer, 0, len));
        }
        System.out.println(sb);
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        doGet(request, response);
    }
}

5.4 HttpServletRequest应用
5.4.1 获取请求参数
form.html

<form action="/chapter05/RequestParamsServlet" method="POST">
    用户名：<input type="text" name="username"><br>
    密 码：<input type="password" name="password"><br>
    爱 好：
    <input type="checkbox" name="hobby" value="sing">唱
    <input type="checkbox" name="hobby" value="dance">跳
        <input type="checkbox" name="hobby" value="rap">rap
    <input type="checkbox" name="hobby" value="basketball">篮球<br>
    <input type="submit" value="提交">
</form>

RequestParamsServlet.java

package Java_Web.Five; 
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class RequestParamsServlet extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        String name = request.getParameter("username");
        String password = request.getParameter("password");
        System.out.println("用户名：" + name);
        System.out.println("密   码：" + password);
        String[] hobbys= request.getParameterValues("hobby");
        System.out.print("爱好：");
        for (int i = 0; i < hobbys.length; i++) {
            System.out.print(hobbys[i]+" ");
        }
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        doGet(request, response);
    }
}

5.4.2 请求参数的中文乱码问题
RequestParamsServlet.java中设置中文编码即可

request.setCharacterEncoding("gbk");

5.4.3 获取网络连接信息
RequestNetServlet.java

package Java_Web.Five; 
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class RequestNetServlet extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        response.setContentType("text/html ;charset=utf-8");
        PrintWriter out = response.getWriter();
        out.println("getRemoteAddr : " + request.getRemoteAddr() + "<br>");
        out.println("getRemoteHost : " + request.getRemoteHost() + "<br>");
        out.println("getRemotePort : " + request.getRemotePort() + "<br>");
        out.println("getLocalAddr : " + request.getLocalAddr() + "<br>");
        out.println("getLocalName : " + request.getLocalName() + "<br>");
        out.println("getLocalPort : " + request.getLocalPort() + "<br>");
        out.println("getServerName : " + request.getServerName() + "<br>");
        out.println("getServerPort : " + request.getServerPort() + "<br>");
        out.println("getScheme : " + request.getScheme() + "<br>");
        out.println("getRequestURL : " + request.getRequestURL() + "<br>");
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        doGet(request, response);
    }
}

5.4.4 通过Request对象传递数据
setAttribute()方法，getAttribute()方法，removeAttribute()方法，getAttributeNames()方法
5.5 RequestDispatcher对象的应用
5.5.1 RequestDispatcher接口
5.5.2 请求转发
RequestForwardServlet.java

package Java_Web.Five; 
import java.io.IOException;
import javax.servlet.*;
import javax.servlet.http.*;
public class RequestForwardServlet extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        response.setContentType("text/html;charset=utf-8");
        // 将数据存储到request对象中
        request.setAttribute("company", "阿里巴巴");        
        RequestDispatcher dispatcher = request.getRequestDispatcher("/ResultServlet");
        dispatcher.forward(request, response);
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        doGet(request, response);
    }
}

ResultServlet.java

package Java_Web.Five;  
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class ResultServlet extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        response.setContentType("text/html;charset=utf-8");
        PrintWriter out = response.getWriter();// 获取PrintWriter对象用于输出信息
        String company = (String) request.getAttribute("company");// 获取request请求对象中保存的数据
        if (company != null) {
            out.println("公司名称：" + company + "<br>");
        }
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        doGet(request, response);
    }
}

然后web.xml中配置他俩的映射，访问

5.5.3 请求包含
IncludingServlet.java

package Java_Web.Five; 
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class IncludingServlet extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        PrintWriter out = response.getWriter();
        RequestDispatcher rd = request.getRequestDispatcher("/IncludedServlet?p1=fuck");
        out.println("before including" + "<br>");
        rd.include(request, response);
        out.println("after including" + "<br>");
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        doGet(request, response);
    }
}

IncludedServlet.java

package Java_Web.Five;  
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class IncludedServlet extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        // 设置响应时使用的字符编码
        response.setContentType("text/html;charset=utf-8");
        response.setCharacterEncoding("utf-8");
        PrintWriter out = response.getWriter();
        out.println("中国" + "<br>");
        out.println("URI:" + request.getRequestURI() + "<br>");
        out.println("QueryString:" + request.getQueryString() + "<br>");
        out.println("parameter p1:" + request.getParameter("p1") + "<br>");
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        doGet(request, response);
    }
}

然后web.xml中配置他俩的映射，访问

第六章会话及其会话技术
6.1 会话概述
https://www.cnblogs.com/luoxn28/p/5513789.html
6.2 Cookie对象
6.2.1 什么是Cookie
https://blog.csdn.net/qq_17452939/article/details/80901985
6.2.2 Cookie API
https://blog.csdn.net/u011541946/article/details/90273259
6.3 Cookie之显示用户上次访问时间
源代码编译时报错，因为date.toLocaleString()已过时，我用DateFormat.format(Date date)进行了取代
LastAccessServlet.java

package Java_Web.Six; 
import java.io.IOException;
import java.util.Date;
import java.text.SimpleDateFormat;
import javax.servlet.ServletException;
import javax.servlet.http.*;
public class LastAccessServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        // 指定服务器输出内容的编码方式UTF-8，防止发生乱码
        response.setContentType("text/html;charset=utf-8");
        String lastAccessTime = null;
        // 获取所有的cookie，并将这些cookie存放在数组中
        Cookie[] cookies = request.getCookies();
        for (int i = 0; cookies != null && i < cookies.length; i++) {
            // 如果cookie的名称为lastAccess,则获取该cookie的值
            if ("lastAccess".equals(cookies[i].getName())) {
                lastAccessTime = cookies[i].getValue();
                break;
            }
        }
        // 判断是否存在名称为lastAccess的cookie
        if (lastAccessTime == null) {
            response.getWriter().print("您是首次访问本站！！！");
        } 
        else {
             response.getWriter().print("您上次的访问时间是： " + lastAccessTime);
        }
        // 创建cookie,将当前时间作为cookie的值发送给客户端
        String currentTime = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss").format(new Date());
        Cookie cookie = new Cookie("lastAccess", currentTime);
        // 发送 cookie
        response.addCookie(cookie);
    }
   protected void doPost(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {
        // TODO Auto-generated method stub
        this.doPost(req, resp);
    }
}

6.4 Session对象
6.4.1 什么是Session
https://blog.csdn.net/q_sea__/article/details/79430215
6.4.2 HttpSession API
https://blog.csdn.net/u011541946/article/details/90442127
6.4.3 Session 超时管理
https://www.cnblogs.com/d0minic/p/12258853.html
6.5 Session之实现购物车
ListBookServlet.java

package Java_Web.Six; 
import java.io.*;
import java.util.*;
import javax.servlet.http.*;
import javax.servlet.ServletException;

class Book implements Serializable {
    private static final long serialVersionUID = 1L;
    private String id;
    private String name;
    public Book() {
    }
    public Book(String id, String name) {
        this.id = id;
        this.name = name;
    }
    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
}
class BookDB {
    private static Map<String, Book> books = new LinkedHashMap<String, Book>();
    static {
        books.put("1", new Book("1", "javaweb开发"));
        books.put("2", new Book("2", "jdbc开发"));
        books.put("3", new Book("3", "java基础"));
        books.put("4", new Book("4", "struts开发"));
        books.put("5", new Book("5", "spring开发"));
    }
    // 获得所有的图书
    public static Collection<Book> getAll() {
        return books.values();
    }
    // 根据指定的id获得图书
    public static Book getBook(String id) {
        return books.get(id);
    }
}
public class ListBookServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
    public void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        resp.setContentType("text/html;charset=utf-8");
        PrintWriter out = resp.getWriter();
        Collection<Book> books = BookDB.getAll();
        out.write("本站提供的图书有：<br>");
        for (Book book : books) {
            String url = "/chapter06/PurchaseServlet?id=" + book.getId();
            out.write(book.getName() + "<a href='" + url 
                    + "'>点击购买</a><br>");
        }
    }
}

PurchaseServlet.java
换共有类：

public class PurchaseServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
    @SuppressWarnings("unchecked")
    public void doGet(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {
        // 获得用户购买的商品
        String id = req.getParameter("id");
        if (id == null) {
            // 如果id为null，重定向到ListBookServlet页面
            String url = "/chapter06/ListBookServlet";
            resp.sendRedirect(url);
            return;
        }
        Book book = BookDB.getBook(id);
        // 创建或者获得用户的Session对象
        HttpSession session = req.getSession();
        // 从Session对象中获得用户的购物车
        List<Book> cart = (List) session.getAttribute("cart");
        if (cart == null) {
            // 首次购买，为用户创建一个购物车(List集合模拟购物车)
            cart = new ArrayList<Book>();
            // 将购物城存入Session对象
            session.setAttribute("cart", cart);
        }
        // 将商品放入购物车
        cart.add(book);
        // 创建Cookie存放Session的标识号
        Cookie cookie = new Cookie("JSESSIONID", session.getId());
        cookie.setMaxAge(60 * 30);
        cookie.setPath("/chapter06");
        resp.addCookie(cookie);
        // 重定向到购物车页面
        String url = "/chapter06/CartServlet";
        resp.sendRedirect(url);
    }
}

CartServlet.java
换共有类：

public class CartServlet extends HttpServlet {
    @SuppressWarnings("unchecked")
    public void doGet(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {
        resp.setContentType("text/html;charset=utf-8");
        PrintWriter out = resp.getWriter();
        // 变量cart引用用户的购物车
        List<Book> cart = null;
        // 变量pruFlag标记用户是否买过商品
        boolean purFlag = true;
        // 获得用户的session
        HttpSession session = req.getSession(false);
        // 如果session为null，purFlag置为false
        if (session == null) {
            purFlag = false;
        } 
        else {
            // 获得用户购物车
            cart = (List) session.getAttribute("cart");
            // 如果用的购物车为null，purFlag置为false
            if (cart == null) {
                purFlag = false;
            }
        }
        /*如果purFlag为false，表明用户没有购买图书 重定向到ListServlet页面*/
        if (!purFlag) {
            out.write("对不起！您还没有购买任何商品！<br>");
        } else {
            // 否则显示用户购买图书的信息
            out.write("您购买的图书有：<br>");
            double price = 0;
            for (Book book : cart) {
                out.write(book.getName() + "<br>");
            }
        }
    }
}

访问http://localhost:8080/chapter06/ListBookServlet.java

6.6 Session之实现用户登录
Login.html

<form name="reg" action="/chapter06/LoginServlet" method="post">
    用户名: <input name="username" type="text" /><br/>
    密码：   <input name="password" type="password" /><br/>
            <input type="submit" value="提交" id="bt" />
</form>

IndexServlet.java

package Java_Web.Six; 
import java.io.*;
import java.util.*;
import javax.servlet.http.*;
import javax.servlet.ServletException;
class User {
    private String username;
    private String password;
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }   
}
public class IndexServlet extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        // 解决乱码问题
        response.setContentType("text/html;charset=utf-8");
        // 创建或者获取保存用户信息的Session对象
        HttpSession session = request.getSession();
        User user = (User) session.getAttribute("user");
        if (user == null) {
            response.getWriter().print("您还没有登录，请<a href='/chapter06/Login.html'>登录</a>");
        } 
        else {
            response.getWriter().print("您已登录，欢迎你，" + user.getUsername() + "！");
            response.getWriter().print("<a href='/chapter06/LogoutServlet'>退出</a>");
            // 创建Cookie存放Session的标识号
            Cookie cookie = new Cookie("JSESSIONID", session.getId());
            cookie.setMaxAge(60 * 30);
            cookie.setPath("/chapter06");
            response.addCookie(cookie);
        }
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        doGet(request, response);
    }
}

LoginServlet.java
换共有类：

public class LoginServlet extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        response.setContentType("text/html;charset=utf-8");
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        PrintWriter pw = response.getWriter();
        //假设正确的用户名 是Du1in9 密码是123
        if (("Du1in9").equals(username) && ("123").equals(password)) {
            User user = new User();
            user.setUsername(username);
            user.setPassword(password);
            request.getSession().setAttribute("user", user);
            response.sendRedirect("/chapter06/IndexServlet");
        } 
        else {
            pw.write("用户名或密码错误，登录失败");
        }
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        doGet(request, response);
    }
}

LogoutServlet.java
换共有类：

public class LogoutServlet extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        // 将Session对象中的User对象移除
        request.getSession().removeAttribute("user");
        response.sendRedirect("/chapter06/IndexServlet");
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        doGet(request, response);
    }
}

访问http://localhost:8080/chapter06/IndexServlet

6.7 Session之实现验证码
Login.html

<form name="reg" action="/chapter06/LoginServlet" method="post">
        用户名: <input name="username" type="text" /><br /> 
        密码： <input name="password" type="password" /><br /> 
        验证码：<input type="text" name="check_code"> 
<img src="/chapter06/CheckServlet"><br>
        <input type="submit" value="提交" id="bt" />
</form>

CheckServlet.java

package Java_Web.Six; 
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.awt.*;
import java.awt.image.*;
import javax.imageio.ImageIO;
public class CheckServlet extends HttpServlet{
    private static int WIDTH = 60; //验证码图片宽度
    private static int HEIGHT = 20; //验证码图片高度
    public void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException{     
        HttpSession session = request.getSession();
        response.setContentType("image/jpeg");
        ServletOutputStream sos = response.getOutputStream();
        //设置浏览器不要缓存此图片
        response.setHeader("Pragma","No-cache");
        response.setHeader("Cache-Control","no-cache");
        response.setDateHeader("Expires", 0);
        //创建内存图象并获得其图形上下文
        BufferedImage image = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB); 
        Graphics g = image.getGraphics();
        //产生随机的认证码
        char [] rands = generateCheckCode();
        //产生图像
        drawBackground(g);
        drawRands(g,rands);
        //结束图像的绘制过程，完成图像
        g.dispose();
        //将图像输出到客户端
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        ImageIO.write(image, "JPEG", bos);
        byte [] buf = bos.toByteArray();
        response.setContentLength(buf.length);
        //下面的语句也可写成：bos.writeTo(sos);
        sos.write(buf);
        bos.close();
        sos.close();
        //将当前验证码存入到Session中
        session.setAttribute("check_code",new String(rands));
        //直接使用下面的代码将有问题，Session对象必须在提交响应前获得
        //request.getSession().setAttribute("check_code",new String(rands));
    }
       //生成一个4字符的验证码
    private char [] generateCheckCode()
    {
        //定义验证码的字符表
        String chars = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
        char [] rands = new char[4];
        for(int i=0; i<4; i++)
        {
            int rand = (int)(Math.random() * 36);
            rands[i] = chars.charAt(rand);
        }
        return rands;
    }
    private void drawRands(Graphics g , char [] rands)
    {
        g.setColor(Color.BLACK);
        g.setFont(new Font(null,Font.ITALIC|Font.BOLD,18));
        //在不同的高度上输出验证码的每个字符     
        g.drawString("" + rands[0],1,17);
        g.drawString("" + rands[1],16,15);
        g.drawString("" + rands[2],31,18);
        g.drawString("" + rands[3],46,16);
        System.out.println(rands);
    }
    private void drawBackground(Graphics g)
    {
        //画背景
        g.setColor(new Color(0xDCDCDC));
        g.fillRect(0, 0, WIDTH, HEIGHT);
        //随机产生120个干扰点
        for(int i=0; i<120; i++)
        {
            int x = (int)(Math.random() * WIDTH);
            int y = (int)(Math.random() * HEIGHT);
            int red = (int)(Math.random() * 255);
            int green = (int)(Math.random() * 255);
            int blue = (int)(Math.random() * 255);
            g.setColor(new Color(red,green,blue));      
            g.drawOval(x,y,1,0);
        }
    }
}

LoginServlet.java

package Java_Web.Six; 
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.*;
import javax.servlet.http.*;
class User {
    private String username;
    private String password;
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }   
}
public class LoginServlet extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        response.setContentType("text/html;charset=utf-8");
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        String checkCode = request.getParameter("check_code");
        String savedCode = (String) request.getSession().getAttribute("check_code");
        PrintWriter pw = response.getWriter();
        if (("Du1in9").equals(username) && ("123").equals(password)&& checkCode.equals(savedCode)) {
            User user = new User();
            user.setUsername(username);
            user.setPassword(password);
            request.getSession().setAttribute("user", user);
            response.sendRedirect("/chapter06/IndexServlet");
        } 
        else if (checkCode.equals(savedCode)) {
            pw.write("用户名或密码错误，登录失败");
        } 
        else {
            pw.write("验证码错误");
        }
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        doGet(request, response);
    }
}

访问http://localhost:8080/chapter06/Login.html

第七章 JSP技术
7.1 JSP概述
7.1.1 什么是JSP
https://www.runoob.com/jsp/jsp-intro.html
simple.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"%>
<html>
<title>boy next ♂ door</title>
<body>
    当前访问时间是：
    <%out.print(new java.util.Date().toLocaleString());%>
</body>
</html>

访问http://localhost:8080/chapter07/simple.jsp

7.1.2 JSP运行原理
https://zhidao.baidu.com/question/476724087.html
7.2 JSP基本语法
JSP注释信息不会被发送到客户瑞
comment.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"%>
<html>
<head>
<title>Insert title here</title>
</head>
<body>
<%-- 这个是注释内容 --%>
</body>
</html>

7.3 JSP指令
①修改报错页面
page.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"%>
<html>
<head>
<title>Insert title here</title>
</head>
<body>
<%int a=1/0;%>
</body>
</html>

page1.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8" errorPage="error.jsp"%>
<html>
<head>
<title>Insert title here</title>
</head>
<body>
<%int a=1/0;%>
</body>
</html>

error.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"%>
<html>
<head>
<title>Insert title here</title>
</head>
<body>
<h2>抱歉♂服务器出现故障♂正在解决♂请稍候。。。。。。。</h2>
</body>
</html>

②通用报错页面
web.xml

  <error-page>
    <error-code>404</error-code>
    <location>/404.jsp</location>
  </error-page>
  <error-page>
    <error-code>500</error-code>
    <location>/500.jsp</location>
  </error-page>

404.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"%>
<html>
<head>
<title>Insert title here</title>
</head>
<body>
<h2>404：你他妈在访问什么玩意</h2>
</body>
</html>

500.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"%>
<html>
<head>
<title>Insert title here</title>
</head>
<body>
<h2>通用500错误处理页面</h2>
</body>
</html>

访问http://localhost:8080/chapter07/page.jsp

访问http://localhost:8080/chapter07/abcdefg.jsp

7.4 JSP隐式对象
7.4.1 隐式对象
7.4.2 out对象
out.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"%>
<html>
<head>
<title>Insert title here</title>
</head>
<body>
<%
   out.println("first line<br>");
   response.getWriter().println("second line<br>");
%>  
</body>
</html>

out1.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8" buffer="0kb"%>
<html>
<head>
<title>Insert title here</title>
</head>
<body>
<%
   out.println("first line<br>");
   response.getWriter().println("second line<br>");
%>  
</body>
</html>

7.4.3 pageContext对象
pageContext.jsp

<%
    HttpServletRequest req=(HttpServletRequest)pageContext.getRequest();
    String x = request.getRemoteAddr();
    out.println("本机的IP地址为："+x);      
%>

访问http://127.0.0.1:8080/chapter07/pageContext.jsp

pageContextDemo.jsp

<%
    pageContext.setAttribute("company", "阿里巴巴",pageContext.PAGE_SCOPE);
    Object x = pageContext.getAttribute("company",pageContext.PAGE_SCOPE);
    out.println("公司名称为：" + x);
%>

7.4.4 exception对象
price.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"%>
<%@ page errorPage="execp.jsp"%>
<%
    String p=request.getParameter("price");
    double x=Double.parseDouble(p);
    out.println("Total price:"+x*5);
%>

execp.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"%>
<%@ page isErrorPage="true"%>
<%
    out.println("exception.toString:"+"<br>");
    out.println(exception.toString());
    out.println("<br>");
    out.println("exception.getMessage():"+"<br>");
    out.println(exception.getMessage());
%>

访问http://localhost:8080/chapter07/price.jsp?price=3.5

访问http://localhost:8080/chapter07/price.jsp?price=Du1in9

7.5 JSP标签
7.5.1 <jsp:include>标签
included.jsp

<%@ page contentType="text/html;charset=GB2312"%>
<%Thread.sleep(2000);%>
你~<br>
<jsp:include page="included1.jsp" flush="true" />

included1.jsp

<%@ page contentType="text/html;charset=GB2312"%>
<%Thread.sleep(2000);%>
是~<br>
<jsp:include page="included2.jsp" flush="true" />

included2.jsp

<%@ page contentType="text/html;charset=GB2312"%>
<%Thread.sleep(2000);%>
猪~<br>

访问http://localhost:8080/chapter07/included.jsp

7.5.2 <jsp:forward>标签
jspforward.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"%>
<jsp:forward page="welcome.jsp" />

welcome.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"%>
<html>
<title>Insert title here</title>
<body>
    你好，欢迎进入首页，当前访问时间是：
    <%out.print(new java.util.Date());%>
</body>
</html>

第八章 JavaBean组件
8.1 JavaBean概述
https://blog.csdn.net/keep12moving/article/details/92666633
8.2 反射（略）
8.3 内省（略）
8.4 JSP标签访问JavaBean
8.4.1 <jsp:useBean>标签
Manager.java

package Java_Web.Eight; 
class Employee {
    private String company;
    public String getCompany() {
        return company;
    }
    public void setCompany(String company) {
        this.company = company;
    }
}
public class Manager extends Employee {
    private double bonus;
    public double getBonus() {
        return bonus;
    }
    public void setBonus(double bonus) {
        this.bonus = bonus;
    }
}

useBean.jsp

<%@ page language="java" pageEncoding="GBK"%>
<html>
<body>
    <jsp:useBean id="manager" scope="page" class="Java_Web.Eight.Manager" />
</body>
</html>

8.4.2 <jsp:setProperty>标签
①property属性单独使用
setProperty.jsp

<%@ page language="java" pageEncoding="GBK" import="Java_Web.Eight.Manager"%>
<html>
<body>
        <jsp:useBean id="manager" class="Java_Web.Eight.Manager" />
        <jsp:setProperty name="manager" property="bonus" />
        <%
            manager = (Manager) pageContext.getAttribute("manager");
            out.write("bonus属性的值为:"+manager.getBonus());
        %>
</body>
</html>

访问http://localhost:8080/chapter08/setProperty.jsp?bonus=500

修改Manager.java

package Java_Web.Eight; 
class Employee {
    private String company;
    public String getCompany() {
        return company;
    }
    public void setCompany(String company) {
        this.company = company;
    }
}
public class Manager extends Employee {
    private double bonus=500;
    public double getBonus() {
        return bonus;
    }
    public void setBonus(double bonus) {
        this.bonus = bonus;
    }
}

访问http://localhost:8080/chapter08/setProperty.jsp

修改setProperty.jsp

<%@ page language="java" pageEncoding="GBK" import="Java_Web.Eight.Manager"%>
<html>
<body>
        <jsp:useBean id="manager" class="Java_Web.Eight.Manager" />
        <jsp:setProperty name="manager" property="*" />
        <%
            manager = (Manager) pageContext.getAttribute("manager");
            out.write("bonus属性的值为:"+manager.getBonus()+"<br />");
            out.write("company属性的值为:"+manager.getCompany());
        %>
</body>
</html>

访问http://localhost:8080/chapter08/setProperty.jsp?bonus=600&company=阿里巴巴

②property属性和param属性混合使用
setProperty.jsp

<body>
        <form action="">
              公司<input  type="text" name="corp"> <br/>
              奖金<input  type="text" name="reward"> <br/>  
                  <input  type="submit" value="提交">     
        </form>
       <jsp:useBean id="manager" class="Java_Web.Eight.Manager" />
       <jsp:setProperty name="manager" property="company" param="corp" />
       <jsp:setProperty name="manager" property="bonus" param="reward" />
       <%
            manager = (Manager) pageContext.getAttribute("manager");
            out.write("bonus属性的值为:"+manager.getBonus()+"<br />");
            out.write("company属性的值为:"+manager.getCompany());
       %>
</body>

③property属性和value属性混合使用
setProperty.jsp

<body>
        <jsp:useBean id="manager" class="Java_Web.Eight.Manager" />
        <jsp:setProperty name="manager" property="company" value="阿里巴巴" />
        <jsp:setProperty name="manager" property="bonus" value="1000.0" />
        <%
            manager = (Manager) pageContext.getAttribute("manager");
            out.write("bonus属性的值为:"+manager.getBonus()+"<br />");
            out.write("company属性的值为:"+manager.getCompany()); 
        %>
</body>

setProperty.jsp

<%@ page language="java" pageEncoding="GBK" import="Java_Web.Eight.Manager" import="java.util.Date" import="java.text.SimpleDateFormat"%>
<html>
<body>
    <% 
        Date date = new Date();
        pageContext.setAttribute("date", date);
    %>    
    <jsp:useBean id="manager" class="Java_Web.Eight.Manager" />
    <jsp:setProperty name="manager" property="birthday" value="${date }" />
    <%
        manager = (Manager) pageContext.getAttribute("manager");
        String formatDate = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss").format(manager.getBirthday());
        out.write("birthday属性的值为:"+formatDate);
    %>
</body>
</html>

Manager.java

package Java_Web.Eight;
import java.util.Date;
class Employee {
    private String company;
    public String getCompany() {
        return company;
    }
    public void setCompany(String company) {
        this.company = company;
    }
}
public class Manager extends Employee {
    private double bonus = 500.0;
    private Date birthday;
    public Date getBirthday() {
        return birthday;
    }
    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }
    public double getBonus() {
        return bonus;
    }
    public void setBonus(double bonus) {
        this.bonus = bonus;
    }
}

8.4.3 <jsp:getProperty>标签
User.java

package Java_Web.Eight;
public class User {
    private String name;
    private String gender;
    private String education;
    private String email;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getGender() {
        return gender;
    }
    public void setGender(String gender) {
        this.gender = gender;
    }
    public String getEducation() {
        return education;
    }
    public void setEducation(String education) {
        this.education = education;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
}

<body>
       <form action="/chapter08/userInfo.jsp" method="post">
          姓名:<input type="text" name="name" /> <br />
          性别:<input type="radio" name="gender" value="man" checked="checked" />man
               <input type="radio" name="gender" value="woman" />woman   <br/>
          学历:<select name="education">
                    <option value="select">请选择</option>
                    <option value="high_school_student">high_school_student</option>
                    <option value="undergraduate">undergraduate</option>
                    <option value="graduate">graduate</option>
                    <option value="doctor">doctor</option>
                </select>  <br/>
          邮箱:<input type="text" name="mail" /> <br />
               <input type="submit" value="提交"/>
       </form>
</body>

userInfo.jsp

<body>
        <jsp:useBean id="user" class="Java_Web.Eight.User" />
        <jsp:setProperty name="user" property="*" />
        <jsp:setProperty name="user"  property="email" param="mail" />
        姓名:<jsp:getProperty name="user" property="name" />  <br />
        性别:<jsp:getProperty name="user" property="gender" /> <br />
        学历:<jsp:getProperty name="user" property="education" /> <br />
        邮箱:<jsp:getProperty name="user" property="email" /> 
</body>

8.5 BeanUtils 工具（略）
第九章 JSP开发模型
9.1 JSP开发模型
https://blog.csdn.net/zl5230/article/details/105851338
9.2 案例
Calculator.java

package Java_Web.Nine;
import java.math.BigDecimal;
import java.util.HashMap;
import java.util.Map;
import java.util.regex.Pattern;
public class Calculator {
    // firstNum表示第一个运算数
    private String firstNum;
    // secondNum表示第二个运算数
    private String secondNum;
    // operator表示运算符
    private char operator;
    // error用于封装错误信息
    private Map<String, String> errors = new HashMap<String, String>();

    // 属性setter和getter方法
    public Map<String, String> getErrors() {
        return errors;
    }
    public void setErrors(Map<String, String> errors) {
        this.errors = errors;
    }
    public String getFirstNum() {
        return firstNum;
    }
    public void setFirstNum(String firstNum) {
        this.firstNum = firstNum;
    }
    public String getSecondNum() {
        return secondNum;
    }
    public void setSecondNum(String secondNum) {
        this.secondNum = secondNum;
    }
    public char getOperator() {
        return operator;
    }
    public void setOperator(char operator) {
        this.operator = operator;
    }
    /*calculate()方法根据传入的运算数和符号进行运算*/
    public String calculate() {
        BigDecimal result = null;
        BigDecimal first = new BigDecimal(firstNum);
        BigDecimal second = new BigDecimal(secondNum);
        switch (operator) {
        case '+':
            result = first.add(second);
            break;
        case '-':
            result = first.subtract(second);
            break;
        case '*':
            result = first.multiply(second);
            break;
        case '/':
            if ("0".equals(secondNum)) {
                throw new RuntimeException("除数不能为0！");
            }
            result = first.divide(second);
            break;
        default:
            break;
        }
        return result.toString();
    }
    /*validate()方法用于验证表单传入的数据是否合法*/
    public boolean validate() {
        // flag是标识符，如果数据合法flag为true，反之为false
        boolean flag = true;
        Pattern p = Pattern.compile("\\d+");// 正则表达式，匹配数字
        if (firstNum == null || "".equals(firstNum)) { // 判断不能为空
            errors.put("firstNum", "第一个运算数不能为空");
            flag = false;
        } else if (!p.matcher(firstNum).matches()) { // 判断不能为非数字
            errors.put("firstNum", "第一个运算数必须为数字");
            flag = false;
        }
        if (secondNum == null || "".equals(secondNum)) { 
            errors.put("secondNum", "第二个运算数不能为空");
            flag = false;
        } else if (!p.matcher(secondNum).matches()) {
            errors.put("secondNum", "第二个运算数必须为数字");
            flag = false;
        }
        return flag;
    }
}

calculator.jsp

<%@ page language="java" pageEncoding="GBK" import="java.util.Map"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
    <head>
        <title>calculator</title>
    </head>
    <body>
        <jsp:useBean id="calculator" class="Java_Web.Nine.Calculator" />
        <jsp:setProperty property="*" name="calculator" />
        <%
            if (calculator.validate()) {
        %>
        <font color="green">运算结果: 
        <jsp:getProperty property="firstNum" name="calculator" />
        <jsp:getProperty property="operator" name="calculator" />
        <jsp:getProperty property="secondNum" name="calculator" />
        =<%=calculator.calculate()%></font>
        <%
            } 
            else {
                Map<String, String> errors = calculator.getErrors();
                pageContext.setAttribute("errors", errors);
            }
        %>
        <form action="" method="post">
            第一个运算数：<input type="text" name="firstNum" /> 
            <font color="red">${errors.firstNum}</font> <br />
            运算符: <select name="operator" style="margin-left: 100px">
                        <option value="+">+</option>
                        <option value="-">-</option>
                        <option value="*">*</option>
                        <option value="/">/</option>
                    </select> <br /> 
            第二个运算数： <input type="text" name="secondNum" /> 
            <font color="red">${errors.secondNum}</font> <br /> 
            <input type="submit" value="计算" />
        </form>
    </body>
</html>

【Java Web 程序开发】学习笔记

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