javaweb简单登录功能(视频学习总结)
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内容图文
一，需求
用户登录案例需求：
1，编写login.html登录页面
username & password两个输入框
2，使用Druid数据库连接池技术，操作mysql
3，使用JdbcTemplate技术封装JDBC
4，登录成功后跳转到succeedServlet展示：登录成功！{用户名}，欢迎您
5，登录失败跳转到failServlet展示：登录失败，用户名或密码错误
二，准备
1，我的项目结构预览
2，数据库配置文件 druid.properties
driverClassName = com.mysql.jdbc.Driver
url = jdbc:mysql:///javawebdemo
user = root
pwd = 36916280
# 初始化连接数量
initialSize = 5
# 最大连接数
maxActive = 10
# 最大等待时间
maxWait = 3000
3，创建数据库及表
CREATE DATABASE javawebdemo;
USE javawebdemo;
CREATE TABLE USER(
id INT PRIMARY KEY AUTO_INCREMENT,
username VARCHAR(20) UNIQUE,
password VARCHAR(20) NOT NULL
);
参见：https://blog.csdn.net/johnfht/article/details/104377177
4，编写登录页面 login.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>用户登录</title>
</head>
<body>
<h1>用户登录</h1>
<form action="" method="post">
<p>用户名：<input type="text" name="username"></p>
<p>密码：<input type="password" name="password"></p>
<p><input type="submit" value="登录"></p>
</form>
</body>
</html>
三，后端代码
1，//用户的实体类 User.java
package com.domain;
//用户的实体类
public class User {
private int id;
private String username;
private String password;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
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;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", username='" + username + '\'' +
", password='" + password + '\'' +
'}';
}
}
2，//JDBC工具类 JDBCUtils.java
package com.util;
import com.alibaba.druid.pool.DruidDataSourceFactory;
import javax.sql.DataSource;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;
//JDBC工具类 使用Durid连接池
public class JDBCUtils {
private static DataSource ds ;
static {
try {
//1.加载配置文件
Properties pro = new Properties();
//使用ClassLoader加载配置文件，获取字节输入流
InputStream is = JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties");
pro.load(is);
//2.初始化连接池对象
ds = DruidDataSourceFactory.createDataSource(pro);
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
// 获取连接池对象
public static DataSource getDataSource(){
return ds;
}
//获取连接Connection对象
public static Connection getConnection() throws SQLException {
return ds.getConnection();
}
}
4，//操作数据库中User表的类 UserDao.java
package com.dao;
import com.domain.User;
import com.util.JDBCUtils;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
//操作数据库中User表的类
public class UserDao {
//声明JDBCTemplate对象共用
private JdbcTemplate template = new JdbcTemplate(JDBCUtils.getDataSource());
//登录方法
public User login(User loginUser){
try {
//1.编写sql
String sql = "select * from user where username = ? and password = ?";
//2.调用query方法
User user = template.queryForObject(sql,
new BeanPropertyRowMapper<User>(User.class),
loginUser.getUsername(), loginUser.getPassword());
return user;
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
}
4，Junit单元测试 UserDaoTest.java
package com.test;
import com.dao.UserDao;
import com.domain.User;
import org.junit.Test;
public class UserDaoTest {
@Test
public void loginTest(){
User loginUser = new User();
loginUser.setUsername("admin");
loginUser.setPassword("123456");
UserDao ud = new UserDao();
User user = ud.login(loginUser);
System.out.println(user);
}
}
成功验证
四，界面控制
1，LoginServlet.java
package com.web.servlet;
import com.dao.UserDao;
import com.domain.User;
import org.apache.commons.beanutils.BeanUtils;
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 java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.Map;
@WebServlet("/loginServlet")
public class LoginServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//1.设置编码
request.setCharacterEncoding("utf-8");
response.setContentType("text/html; charset=utf-8");
/*//2.获取请求参数
String username = request.getParameter("username");
String password = request.getParameter("password");
//3.封装user对象
User loginUser = new User();
loginUser.setUsername(username);
loginUser.setPassword(password);*/
//2.获取所有请求参数
Map<String, String[]> map = request.getParameterMap();
//3.创建User对象
User loginUser = new User();
//3.2使用BeanUtils封装
try {
BeanUtils.populate(loginUser,map);
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
//4.调用UserDao的login方法
UserDao ud = new UserDao();
User user = ud.login(loginUser);
//5.判断user
if(user == null){
//登录失败
request.getRequestDispatcher("/loginFailServlet").forward(request, response);
}else{
//登录成功
//存储数据
request.setAttribute("user", user);
//转发
request.getRequestDispatcher("/loginSucceesServlet").forward(request, response);
}
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request,response);
}
}
2，LoginSucceesServlet.java
package com.web.servlet;
import com.domain.User;
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 java.io.IOException;
@WebServlet("/loginSucceesServlet")
public class LoginSucceesServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//设置编码
request.setCharacterEncoding("utf-8");
response.setContentType("text/html; charset=utf-8");
//获取request域中共享的user对象
User user = (User)request.getAttribute("user");
if(user != null){
//给页面写一句话输出
response.getWriter().write("登录成功，欢迎您：" + user.getUsername());
}
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request,response);
}
}
3，LoginFailServlet.java
package com.web.servlet;
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 java.io.IOException;
@WebServlet("/loginFailServlet")
public class LoginFailServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//设置编码
request.setCharacterEncoding("utf-8");
response.setContentType("text/html; charset=utf-8");
//给页面写一句话输出
response.getWriter().write("登录失败，用户名或密码错误");
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}
}
五，页面展示
1，登录首页
2，登录失败
3，登录成功
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