html调用servlet（JDBC在Servlet中的使用）（1）

1.页面的数据表单

在使用Servlet处理用户请求之前，先准备一个页面，该页面用来提供数据表单。数据表单就是HTML中的...部分，当用户单击Submit按钮提交表单之后，表单中包含的一些变量（或者成为字段）将会被发送到服务器端进行处理。下面编写一个HTML文件，文件代码如下：

add.html

add.html-->请输入部门信息：

部门号：

部门名：

部门人数：

地址：

2.添加数据

Servlet的好处之一就是可以简单地获得表单中的数据。在Servlet中使用JDBC技术实现添加的代码如下：

addServlet.java

packagecom.cn.add;importjava.io.IOException;importjava.io.PrintWriter;importjava.sql.Connection;importjava.sql.DriverManager;importjava.sql.PreparedStatement;importjava.sql.SQLException;importjavax.servlet.ServletException;importjavax.servlet.http.HttpServlet;importjavax.servlet.http.HttpServletRequest;importjavax.servlet.http.HttpServletResponse;publicclassaddServletextendsHttpServlet {/*** Constructor of the object.*/publicaddServlet() {super();

}/*** Destruction of the servlet.
*/publicvoiddestroy() {super.destroy();//Just puts "destroy" string in log//Put your code here}/*** The doGet method of the servlet.

*

* This method is called when a form has its tag value method equals to get.

*

*@paramrequest the request send by the client to the server

*@paramresponse the response send by the server to the client

*@throwsServletException if an error occurred

*@throwsIOException if an error occurred*/publicvoiddoGet(HttpServletRequest request, HttpServletResponse response)throwsServletException, IOException {

response.setContentType("text/html;charset=gb2312");

PrintWriter out=response.getWriter();this.doPost(request, response);

out.flush();

out.close();

}/*** The doPost method of the servlet.

*

* This method is called when a form has its tag value method equals to post.

*

*@paramrequest the request send by the client to the server

*@paramresponse the response send by the server to the client

*@throwsServletException if an error occurred

*@throwsIOException if an error occurred*/publicvoiddoPost(HttpServletRequest request, HttpServletResponse response)throwsServletException, IOException {

System.out.println("到了Servlet！！！");

response.setContentType("text/html;charset=gb2312");

request.setCharacterEncoding("gb2312");

PrintWriter out=response.getWriter();

String id= request.getParameter("id");//获取部门编号String name = request.getParameter("name");//获取部门名称String address = request.getParameter("address");//获取部门所在地址intnum = Integer.parseInt(request.getParameter("num"));//获取部门人数Connection conn =null;//声明一个Connection对象，用来连接数据库PreparedStatement pstmt =null;//声明PreparedStatement对象，用来向数据库插入数据条数据try{//连接到MySQL数据库中的bank数据库模式Class.forName("com.mysql.jdbc.Driver");

System.out.println("创建驱动成功！");//连接数据库conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/bank", "root", "1234");

System.out.println("连接数据库成功！");//插入数据的SQL语句String sql = "INSERT INTO dept(id,d_name,address,empnumber) VALUES(?,?,?,?)";

pstmt=conn.prepareStatement(sql);//设置插入数据的顺序pstmt.setString(1, id);

pstmt.setString(2, name);

pstmt.setString(3, address);

pstmt.setInt(4, num);intresult =pstmt.executeUpdate();//判断执行结果if(result == 1) {

out.print("插入数据成功！");

}else{

out.print("插入数据失败！请重新插入！");

}

}catch(ClassNotFoundException e) {//TODO Auto-generated catch blocke.printStackTrace();

}catch(SQLException e) {//TODO Auto-generated catch blocke.printStackTrace();

}

out.flush();

out.close();

}/*** Initialization of the servlet.

*

*@throwsServletException if an error occurs*/publicvoidinit()throwsServletException {//Put your code here}

}

web.xml

http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">This is the description of my J2EE componentThis is the display name of my J2EE componentaddServletcom.cn.add.addServletaddServlet/servlet/addServletindex.jsp

文件整体框架如下：

3.查看单条数据

一般一条数据的id是唯一的，查看单条记录的时候，可以根据id来查询。HTML页面的代码如下：

showById.html

showById.html-->请输入部门编号：

在该页面中输如id号，点击查找按钮时会进入查询的Servlet，在Servlet中处理根据id查询的操作。根据id查询的Servlet代码如下：

SearchEmployee.java

packagecom.cn.query;importjava.io.IOException;importjava.io.PrintWriter;importjava.sql.Connection;importjava.sql.DriverManager;importjava.sql.PreparedStatement;importjava.sql.ResultSet;importjava.sql.SQLException;importjavax.servlet.ServletException;importjavax.servlet.http.HttpServlet;importjavax.servlet.http.HttpServletRequest;importjavax.servlet.http.HttpServletResponse;publicclassSearchEmployeeextendsHttpServlet {/*** Destruction of the servlet.
*/publicvoiddestroy() {super.destroy();//Just puts "destroy" string in log//Put your code here}/*** The doGet method of the servlet.

*

* This method is called when a form has its tag value method equals to get.

*

*@paramrequest the request send by the client to the server

*@paramresponse the response send by the server to the client

*@throwsServletException if an error occurred

*@throwsIOException if an error occurred*/publicvoiddoGet(HttpServletRequest request, HttpServletResponse response)throwsServletException, IOException {

response.setContentType("text/html;charset=gb2312");

request.setCharacterEncoding("gb2312");

PrintWriter out=response.getWriter();

String id= request.getParameter("id");//获取部门编号Connection conn =null;//声明一个Connection对象，用来连接数据库PreparedStatement pstmt =null;

ResultSet rs=null;try{

Class.forName("com.mysql.jdbc.Driver");

System.out.println("创建驱动成功！");//连接数据库conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/bank", "root", "1234");

System.out.println("连接数据库成功！");

String sql= "SELECT * FROM dept WHERE id = ?";

pstmt=conn.prepareStatement(sql);

pstmt.setString(1, id);

rs=pstmt.executeQuery();

}catch(ClassNotFoundException e) {//TODO Auto-generated catch blocke.printStackTrace();

}catch(SQLException e) {//TODO Auto-generated catch blocke.printStackTrace();

}try{while(rs.next()){

out.print("部门编号："+rs.getString(1)+"\n");

out.print("部门名称："+rs.getString(2)+"\n");

out.print("部门地址："+rs.getString(3)+"\n");

out.print("部门人数："+rs.getString(4)+"\n");

}

}catch(SQLException e) {//TODO Auto-generated catch blocke.printStackTrace();

}

out.flush();

out.close();

}/*** The doPost method of the servlet.

*

* This method is called when a form has its tag value method equals to post.

*

*@paramrequest the request send by the client to the server

*@paramresponse the response send by the server to the client

*@throwsServletException if an error occurred

*@throwsIOException if an error occurred*/publicvoiddoPost(HttpServletRequest request, HttpServletResponse response)throwsServletException, IOException {

response.setContentType("text/html;charset=gb2312");

request.setCharacterEncoding("gb2312");

PrintWriter out=response.getWriter();this.doGet(request, response);

out.flush();

out.close();

}/*** Initialization of the servlet.

*

*@throwsServletException if an error occurs*/publicvoidinit()throwsServletException {//Put your code here}

}

目录结构如下：

4.显示一张表中的全部数据

显示表中全部数据信息的Servlet代码如下：

DeptList.java

packagecom.cn.query;importjava.io.IOException;importjava.io.PrintWriter;importjava.sql.Connection;importjava.sql.DriverManager;importjava.sql.ResultSet;importjava.sql.SQLException;importjava.sql.Statement;importjavax.servlet.ServletException;importjavax.servlet.http.HttpServlet;importjavax.servlet.http.HttpServletRequest;importjavax.servlet.http.HttpServletResponse;publicclassDeptListextendsHttpServlet {/*** The doGet method of the servlet.

*

* This method is called when a form has its tag value method equals to get.

*

*@paramrequest the request send by the client to the server

*@paramresponse the response send by the server to the client

*@throwsServletException if an error occurred

*@throwsIOException if an error occurred*/publicvoiddoGet(HttpServletRequest request, HttpServletResponse response)throwsServletException, IOException {

response.setContentType("text/html;charset=gb2312");

request.setCharacterEncoding("gb2312");

PrintWriter out=response.getWriter();

Connection conn=null;

Statement stmt=null;

ResultSet rs=null;try{

Class.forName("com.mysql.jdbc.Driver");

conn= DriverManager.getConnection("jdbc:mysql://localhost:3306/bank", "root", "1234");

stmt=conn.createStatement();

rs= stmt.executeQuery("SELECT * FROM dept");//在页面中显示表中的所有信息out.println(""+                    "部门表信息"+                    "");

out.println("

部门表信息:

");//循环遍历输出查询结果while(rs.next()){

out.print("部门编号：");

out.print(rs.getString(1)+"\t");

out.print("部门名称：");

out.print(rs.getString(2)+"\t");

out.print("部门地址：");

out.print(rs.getString(3)+"\t");

out.print("部门人数：");

out.print(rs.getString(4)+"\t");

out.print("
");

}

out.print("");

out.close();

}catch(ClassNotFoundException e) {//TODO Auto-generated catch blocke.printStackTrace();

}catch(SQLException e) {//TODO Auto-generated catch blocke.printStackTrace();

}

}publicvoidinit()throwsServletException {//Put your code here}

}