1.编写jsp页面
login.jsp
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>登陆页面</title>
</head>
<body>
<form action="../userCheckServlet" method="post">
请输入用户名：<input type="text" name="username"/><br/>
请输入密码：<input type="password" name="userpwd"/><br/>
<input type="submit" value="登录"/>
<input type="reset"/>
</form>
</body>
</html>success.jsp
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>登陆成功页面</title>
</head>
<body>
${requestScope.u }你好!登陆成功!
</body>
</html>error.jsp
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>登陆失败页面</title>
</head>
<body>
${requestScope.u }，用户不存在或者密码错误。
<a href="byname/login.jsp">单击转跳登陆页面</a>
</body>
</html>2.创建用户和连接数据库的Bean类
UserDao.java
package com.bean;
public class User {
private int id;
private String name;
private String pwd;
private int power;
public User() {}
public User(String name,String pwd) {
this.pwd=pwd;
this.name=name;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPwd() {
return pwd;
}
public void setPwd(String pwd) {
this.pwd = pwd;
}
public int getPower() {
return power;
}
public void setPower(int power) {
this.power = power;
}
}DbConnect.java
package com.bean;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
public class DbConnect {
public static Connection getDBconnection() {
String shujuku = "benzhu";
String url1 ="jdbc:mysql://localhost:3306/"+shujuku;
String uname = "root";
String upwd="123456";
Connection conn=null;
try{
Class.forName("com.mysql.jdbc.Driver");
conn= DriverManager.getConnection(url1, uname, upwd);
System.out.println("哈哈哈哈 连接成功");
}
catch(Exception e){
e.printStackTrace();
}
return conn;
}
public static void Close(Connection conn,Statement stmt,ResultSet rs) {
try{if(rs!=null) rs.close();}catch(Exception e){e.printStackTrace();}
try{if(stmt!=null) stmt.close();}catch(Exception e){e.printStackTrace();}
try{if(conn!=null) conn.close();}catch(Exception e){e.printStackTrace();}
}
}3.创建验证账号密码的Dao类
UserDao.java
package com.dao;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.ArrayList;
import com.bean.DbConnect;
import com.bean.User;
public class UserDao {
public User findUserByuser(User user) {
User user1=null;
try{
Connection conn;
conn = DbConnect.getDBconnection();
String sql="select * from benzhu_user where user_name=? and user_pwd=?";
PreparedStatement st1 = conn.prepareStatement(sql);
st1.setString(1, user.getName());
st1.setString(2, user.getPwd());
ResultSet rs=st1.executeQuery();
if(rs.next()) {
int id = rs.getInt(1);
String name1 = rs.getString(2);
String pwd = rs.getString(3);
int power = rs.getInt(4);
user1 = new User(id,name1,pwd,power);
}
DbConnect.Close(conn, st1, rs);
}
catch(Exception e){
e.printStackTrace();
}
return user1;
}
}4.创建处理jsp页面的servlet
userCheckServlet.java
package com.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 com.bean.User;
import com.dao.UserDao;
@WebServlet("/userCheckServlet")
public class userCheckServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
String name = request.getParameter("username");
String pwd = request.getParameter("userpwd");
User user = new User(name,pwd);
UserDao dao1 = new UserDao();
request.setAttribute("u", name);
if(dao1.findUserByuser(user)!=null) {
request.getRequestDispatcher("byname/success.jsp").forward(request, response);
}
else {
request.getRequestDispatcher("byname/error.jsp").forward(request, response);
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}5.数据库脚本
6.效果图
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