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  • mvc架构的简单登录系统,jsp

    文件结构

    三个jsp文件负责前段界面的实现

    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>

    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>
    View Code

    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>

    javabean文件

    JdbcBean.java

    package data;
    import java.sql.*;
    public class JdbcBean {
          private String DBDriver="com.mysql.jdbc.Driver";
          private String DBUrl="jdbc:mysql://localhost:3306/trade";
          private String DBUser="root";
          private String DBPassword="admin";
          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());
              }
          }
    }
    View Code

    servlet文件

    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 userChart where userId='"+username+"'" +
                       "&&userPassword='"+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("������ѯ�쳣");
            }
            RequestDispatcher rd=request.getRequestDispatcher(toJSP);
            rd.forward(request, response);
        } 
        public void doGet(HttpServletRequest request, 
                          HttpServletResponse response)
          throws ServletException, IOException {
                doPost(request,response);
        }
    }
    View Code

    数据库为mysql,用户名:root;密码:admin。数据库名:trade;表名:userchart

    参考:http://blog.csdn.net/lindonglian/article/details/40581117?utm_source=tuicool&utm_medium=referral

    http://www.xin126.cn/show.asp?id=2504

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  • 原文地址:https://www.cnblogs.com/vactor/p/5553682.html
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