用MVC模式写的jsp连接数据库操作

来源：互联网发布：永恒之塔多玩数据库编辑：程序博客网时间：2024/04/29 20:16

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包中还有一个控制器Servlet,用于处理连接数据库的操作，此次工程用的数据库是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("用户名不能为空");               }               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>用户名</td>        <td><input type="text" name="username"></td>        <td>用户名不能为空</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>

如果登录的用户名和密码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("用户名或密码错误，登录失败!");     %>  </body></html>

输入用户名ming,密码ming

输入用户名lin,密码li

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

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