使用MVC写模式jsp连接到数据库操作

首先用一个JavaBean封装数据库操作,即mvc中的模型

JdbcBean.java

package data;

import java.sql.*;

public class JdbcBean {

	  private String DBDriver="com.mysql.jdbc.Driver";

	  private String DBUrl="jdbc:mysql://localhost:3306/test";

	  private String DBUser="root";

	  private String DBPassword="686175";

	  public Connection conn=null;

	  public ResultSet rs=null;

	  public ResultSet query(String sql)throws Exception{

		  try{

			  Class.forName(DBDriver);

			  conn=DriverManager.getConnection(DBUrl,DBUser,DBPassword);

			  Statement stmt=conn.createStatement();

			  rs=stmt.executeQuery(sql);

			  return rs;

		  }

		  catch(SQLException e){

			  System.out.println(e.getMessage());

		  }

		  return null;

	  }

	  public void update(String sql)throws Exception{

		  try{

			  Class.forName(DBDriver);

			  conn=DriverManager.getConnection(DBUrl,DBUser,DBPassword);

			  Statement stmt=conn.createStatement();

			  stmt.executeUpdate(sql);

			  stmt.close();

			  conn.close();

		  }

		  catch(SQLException e){

			  System.out.println(e.getMessage());

		  }

	  }

}

在src的data包中另一个控制器Servlet,用于处理连接数据库的操作，此次project用的数据库是MySQL

LoginServlet.java

package data;

import java.io.IOException;

import java.sql.ResultSet;

import javax.servlet.RequestDispatcher;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class LoginServlet extends HttpServlet {

	public void doPost(HttpServletRequest request,

			           HttpServletResponse response)

			throws ServletException, IOException {

		String toJSP="";

		request.setCharacterEncoding("gbk");

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

		String username=request.getParameter("username");

		String password=request.getParameter("password");

		String sql="select * from user where username='"+username+"'" +

				   "&&password='"+password+"'";

		JdbcBean jdbc=new JdbcBean();

		try{

			ResultSet rs=jdbc.query(sql);

			if(rs.next()){

				toJSP="success.jsp";

			}

			else{

				toJSP="error.jsp";

			}

			rs.close();

		}

		catch(Exception e){

			System.out.println("发生查询异常");

		}

		RequestDispatcher rd=request.getRequestDispatcher(toJSP);

		rd.forward(request, response);

	}

	public void doGet(HttpServletRequest request,

			          HttpServletResponse response)

	  throws ServletException, IOException {

            doPost(request,response);

    }

}

接下来就是用jsp写的视图，显示页面操作

登录页面login.jsp

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>

<html>

  <head>

    <title>My JSP 'login.jsp' starting page</title>

    <script>

            function myFunction(){

               if(myForm.username.value==""){

                  alert("username不能为空");

               }

               else if(myForm.password.value==""){

                  alert("密码不能为空");

               }

               else{

                  myForm.submit();

               }

            }

    </script>

  </head>

  <body>

  <form action="LoginServlet" method="post" name="myForm">

  <center>

  <table>

     <tr>

        <td>username</td>

        <td><input type="text" name="username"></td>

        <td>username不能为空</td>

     </tr>

     <tr>

        <td>密码</td>

        <td><input type="password" name="password"></td>

        <td>密码不能为空</td>

     </tr>

     <tr>

        <td></td>

        <td><input type="submit" value="提交" onclick="myFunction()">

            <input type="reset" value="取消"></td>

     </tr>

  </table>

  </center>

  </form>

  </body>

</html>

登录成功页面success.jsp

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>

<html>

  <head>

    <title>My JSP 'success.jsp' starting page</title>

  </head>

  <body>

    <%

       out.println("登录成功!");

     %>

  </body>

</html>

假设登录的username和password和存放在数据库的数据对不上，就显示登录错误页面error.jsp

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>

<html>

  <head>

    <title>My JSP 'error.jsp' starting page</title>

  </head>

  <body>

    <%

       out.println("username或password错误，登录失败!");

     %>

  </body>

</html>

输入usernameming,passwordming

输入usernamelin,passwordli

完整代码包:http://download.csdn.net/detail/u011731233/8093745

巴特西

使用MVC写模式jsp连接到数据库操作

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