HttpServletRequest对象代表客户端的请求
HTTP协议之请求
继承关系
通过Request对象进行的常用操作
- 获取客户机信息
- 获取请求头信息
- 获取请求参数
- 利用请求域传递对象（request域对象）
- 重定向和转发的区别
获取客户机信息
获取客户机信息
获取请求头信息
获取请求头信息
- referer 网页来源
- user-agent 浏览器类型
- MSIE IE浏览器
- Firefox 火狐浏览器
- Chrome google浏览器
/**
* 获取客户机的内容 和请求头内容
* @author limaoquan
*
*/
public class RequestServlet1 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//获取IP
String ip = request.getRemoteAddr();
String method = request.getMethod();
String path = request.getContextPath();
System.out.println("IP地址" + ip);
System.out.println("虚拟路径是 "+ path);
System.out.println("请求方式"+ method);
//获取请求头
String referer=request.getHeader("referer");//网页来源(防盗链)
String agent = request.getHeader("user-agent");//判断浏览器(文件下载)
//遍历所有请求头
Enumeration<String> names = request.getHeaderNames();
while(names.hasMoreElements()){
String name = names.nextElement();
System.out.println(name + ":" + request.getHeader(name));
}
System.out.println("------------");
System.out.println("您使用浏览器："+ request.getHeader("user-agent"));
//判断referer是否存在和有效
if(referer!=null&&referer.startsWith("http://localhost/day")){
//不属于盗链
response.setContentType("text/html;charset=utf-8");
response.getWriter().println("机密信息");
}else{
//盗链
response.setContentType("text/html;charset=utf-8");
response.getWriter().println("您的请求盗链");
}
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
获取请求参数（重要）
获取请求参数
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<form action="/day10/reg" method="post">
<table border="1" width="50%">
<tr>
<td>输入姓名</td>
<td><input type="text" name="username"></td>
</tr>
<tr>
<td>输入密码</td>
<td><input type="password" name="password"></td>
</tr>
<tr>
<td>选择性别</td>
<td>
<input type="radio" name="sex" value="man"/>男
<input type="radio" name="sex" value="woman"/>女
</td>
</tr>
<tr>
<td>选择爱好</td>
<td>
<input type="checkbox" name="love" value="lq"/>篮球
<input type="checkbox" name="love" value="zq"/>足球
<input type="checkbox" name="love" value="pq"/>排球
</td>
</tr>
<tr>
<td>选择城市</td>
<td>
<select name="city">
<option value="none">--请选择--</option>
<option value="bj">北京</option>
<option value="sh">上海</option>
<option value="sz">深圳</option>
</select>
</td>
</tr>
<tr>
<td colspan="2"><input type="submit" value="提交"></td>
</tr>
</table>
</form>
</body>
</html>
html界面
public class RegServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
/**
* request获取中文的乱码
* post请求
* setCharacterEncoding(String env) 设置request缓冲区编码
*
* get请求
*
*/
//设置request缓冲区编码
request.setCharacterEncoding("UTF-8");
//获取内容，做其他操作
String username = request.getParameter("username");
String password = request.getParameter("password");
String sex = request.getParameter("sex");
//获取爱好，有过个值
String[] loves = request.getParameterValues("love");
String city = request.getParameter("city");
System.out.println("用户名：" + username);
System.out.println("密码：" + password);
System.out.println("性别：" + sex);
System.out.println("爱好：" + Arrays.toString(loves));
System.out.println("城市：" + city);
System.out.println("==========================");
//获取map集合
Map<String,String[]> map = request.getParameterMap();
//循环遍历
Set<String> keys = map.keySet();
for(String key:keys){
String[] values = map.get(key);
System.out.println(Arrays.toString(values));
}
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
乱码问题解决
- POST请求乱码 ：
request.setCharacterEncoding("utf-8"); - GET请求乱码
-
解决方案一：修改server.xml (尽力不要用方案一)
<Connector port="80" protocol="HTTP/1.1" connectionTimeout="20000" redirectPort="8443" URIEncoding="utf-8"/>
必须有修改tomcat服务器配置文件权限 -
解决方案二：逆向编解码（推荐用）
username = URLEncoder.encode(username, "ISO8859-1");
username = URLDecoder.decode(username, "utf-8");
简化
username = new String(username.getBytes("ISO8859-1"),"utf-8");
重定向和转发
域对象 ServletContext 与 request 的区别：
- ServletContext： 服务器启动，为每个web应用只创建一个ServletContext对象，所有应用共享
- request 只有一次请求的范围
两者方法相似:
- setAttribute();
- getAttribute();
- removeAttribute();
public class RequestServlet2 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//request域设置内容
request.setAttribute("name", "Mango");
//转发(路径服务器端的绝对路径) 转发可以共享request域
request.getRequestDispatcher("/request3").forward(request, response);
//完成重定向(客户端路径) 重定向无法共享request域
//response.sendRedirect("/day10/request3");
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
public class RequestServlet3 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//获取
String value = (String)request.getAttribute("name");
response.setContentType("text/html;charset=UTF-8");
response.getWriter().write("访问到 了 3 " + value);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
转发和重定向的区别
转发
RequestDispatcher rd = request.getRequestDispatcher("/request3");
rd.forward(request, response);
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