servlet+jsp用户登录实现

淡淡的烟草味﹌ 2022-05-27 12:13 187阅读 0赞

项目结构如下：

![20180418163033324][]

登录界面

![20180418163141330][]

登录成功

![20180418163254854][]

登录失败

![20180418163313378][]

user代码段

package bean;
    
    import java.sql.Connection;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    
    import util.DB;
    
    public class user {
    	private String username;
    	private String password;
    	public String getUsername() {
    		return username;
    	}
    	public void setUsername(String username) {
    		this.username = username;
    	}
    	public String getPassword() {
    		return password;
    	}
    	public void setPassword(String password) {
    		this.password = password;
    	}
    	public boolean Check(String username,String password)throws Exception{
    		Connection conn=null;
    		ResultSet rest=null;
    		PreparedStatement prst=null;
    		String sql="select * from user where username=?";
    		boolean flag=false;
    		try{
    			conn=DB.getConn();
    			prst=conn.prepareStatement(sql);
    			prst.setString(1, username);
    			rest=prst.executeQuery();
    			if(rest.next()){
    				if(password.equals(rest.getString("password"))){
    					flag=true;
    				}else{
    					throw new Exception("密码不对哦");
    				}
    			}else{
    				throw new Exception("用户名不存在");
    			}
    		}catch(Exception e){
    			e.printStackTrace();
    		}finally{
    			try {
    				rest.close();
    			} catch (SQLException e) {
    				// TODO Auto-generated catch block
    				e.printStackTrace();
    			}
    			try {
    				prst.close();
    			} catch (SQLException e) {
    				// TODO Auto-generated catch block
    				e.printStackTrace();
    			}
    			try {
    				conn.close();
    			} catch (SQLException e) {
    				// TODO Auto-generated catch block
    				e.printStackTrace();
    			}
    		}
    		return flag;
    	}
    }

DB代码段

package util;
    
    import java.sql.Connection;
    import java.sql.DriverManager;
    
    public class DB {
    	public static Connection getConn(){
    		Connection conn=null;
    		try{
    			String url="jdbc:mysql://localhost/student";
    			String user="root";
    			String password="root";
    			Class.forName("com.mysql.jdbc.Driver");
    			conn=DriverManager.getConnection(url, user, password);
    			if(conn!=null){
    				System.out.println("数据库连接成功！");
    			}
    		}catch(Exception e){
    			e.printStackTrace();
    		}
    		return conn;
    	}
    }

userServlet代码段

package servlet;
    
    import java.io.IOException;
    import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    import bean.user;
    
    /**
     * Servlet implementation class userServlet
     */
    @WebServlet(
    		urlPatterns={"/userServlet"},name="userServlet" 
    		)
    public class userServlet extends HttpServlet {
    	private static final long serialVersionUID = 1L;
           
        /**
         * @see HttpServlet#HttpServlet()
         */
        public userServlet() {
            super();
            // TODO Auto-generated constructor stub
        }
    
    	/**
    	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
    	 */
    	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    		// TODO Auto-generated method stub
    		doPost(request,response);
    	}
    
    	/**
    	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
    	 */
    	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    		// TODO Auto-generated method stub
    		request.setCharacterEncoding("utf-8");//处理表单中文乱码
    		user u=new user();
    		String username,password;
    		try{
    			username=request.getParameter("username");
    			password=request.getParameter("password");
    			if(u.Check(username, password)){
    				u.setUsername(username);
    				u.setPassword(password);
    				request.getSession().setAttribute("use", u);
    				request.getRequestDispatcher("/Success.jsp").forward(request, response);
    			}else{
    				request.getRequestDispatcher("/fail.jsp").forward(request, response);
    			}
    		}catch(Exception e){
    			e.printStackTrace();
    		}
    	}
    
    }

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
    <%
    String path = request.getContextPath();
    String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
    %>
    
    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
    <html>
      <head>
        <base href="<%=basePath%>">
        
        <title>用户登录</title>
        
    	<meta http-equiv="pragma" content="no-cache">
    	<meta http-equiv="cache-control" content="no-cache">
    	<meta http-equiv="expires" content="0">    
    	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    	<meta http-equiv="description" content="This is my page">
    	
    
      </head>
      
      <body>
        <center>
        	<form action="<%=request.getContextPath() %>/userServlet" method="post">
        		<table>
        			<tr>
        				<td>用户名:</td>
        				<td><input type="text" name="username"></td>
        			</tr>
        			<tr>
        				<td>密码:</td>
        				<td><input type="password" name="password"></td>
        			</tr>
        			<tr>
        				<td></td>
        				<td><input type="submit" value="登录"></td>
        			</tr>
        		</table>
        	</form>
        </center>
      </body>
    </html>

success.jsp代码段

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
    <jsp:useBean id="use" class="bean.user" scope="session"></jsp:useBean>
    <%
    String path = request.getContextPath();
    String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
    %>
    
    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
    <html>
      <head>
        <base href="<%=basePath%>">
        
        <title>登录成功</title>
        
    	<meta http-equiv="pragma" content="no-cache">
    	<meta http-equiv="cache-control" content="no-cache">
    	<meta http-equiv="expires" content="0">    
    	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    	<meta http-equiv="description" content="This is my page">
    	
    
      </head>
      
      <body>
        <table>
        			<tr>
        				<td>用户名:</td>
        				<td><jsp:getProperty name="use" property="username"/></td>
        			</tr>
        			<tr>
        				<td>密码:</td>
        				<td><jsp:getProperty name="use" property="password"/></td>
        			</tr>
        		</table>
      </body>
    </html>

fail.jsp代码段

[20180418163033324]: /images/20220527/551eb3138720462da4fa8309ffeafb55.png
[20180418163141330]: /images/20220527/fe53ece5812b4a0180c86a8e5f1c769c.png
[20180418163254854]: /images/20220527/03df314a6a894f5da90f5dca3fd3f506.png
[20180418163313378]: /images/20220527/628a484cb5994b94af01105df6cbc08f.png