Java连接数据库实现用户登录密码验证

目录结构图：

1.在store_db数据库中创建一个t_user表;

在domain包中创建一个User的类：

package com.xxf.domain;

public class User {
	private Integer id;
	private String username;
	private String password;
	private String email;
	private String phone;
	@Override
	public String toString() {
		return "User [id=" + id + ", username=" + username + ", password=" + password + ", email=" + email + ", phone="
				+ phone + "]";
	}
	public Integer getId() {
		return id;
	}
	public void setId(Integer 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;
	}
	public String getEmail() {
		return email;
	}
	public void setEmail(String email) {
		this.email = email;
	}
	public String getPhone() {
		return phone;
	}
	public void setPhone(String phone) {
		this.phone = phone;
	}
}

2.使用dbutils工具类连接数据库；

在util包创建一个JdbcUtil.javad的工具类，要导入dbutils的jar包。

package com.xxf.util;

import java.io.FileInputStream;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

import javax.sql.DataSource;

import com.alibaba.druid.pool.DruidDataSourceFactory;




public class JdbcUtil {

	public static DataSource ds = null;
	static {
		try {
			//1.加载配置文件
			Properties p = new Properties();
			//获取字节码目录
			String path = JdbcUtil.class.getClassLoader().getResource("db.properties").getPath();
			FileInputStream in = new FileInputStream(path);
			p.load(in);
			//ds = BasicDataSourceFactory.createDataSource(p);
			ds = DruidDataSourceFactory.createDataSource(p);
		}catch(Exception e) {
			e.printStackTrace();
		}
	}
	
	public static DataSource getDataSource() {
		return ds;
	}
	
	
	public static Connection getConn() {
		try {
			// 2.连接数据
			return ds.getConnection();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;
	}
	/**
	 * 关闭资源 
	 */
	public static void close(Connection conn,Statement st,ResultSet rs) {
		if (rs != null) {
			try {
				rs.close();
			} catch (SQLException e) {

				e.printStackTrace();
			}
		}
		if (st != null) {
			try {
				st.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}

		if (conn != null) {
			try {
				conn.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
	}
	
}

3.写一个servlet里面实现service的方法；获取请求参数username和password；并实现sql语句的查询功能，进行判断是否有正确。

package com.xxf.servlet;

import java.io.IOException;
import java.sql.SQLException;

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 org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;

import com.xxf.domain.User;
import com.xxf.util.JdbcUtil;

@WebServlet("/login")
public class LoginServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

	protected void service(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		// 获取请求参数
		String username = request.getParameter("username");
		String password = request.getParameter("password");
		System.out.println("username"+username+"password"+password);
		// 连接到数据库，验证用户和密码是否正确
		QueryRunner qr = new QueryRunner(JdbcUtil.getDataSource());
		String sql="select * from t_user where username=? and password=?";
		User user=null;
		try {
			 user=qr.query(sql, new BeanHandler<User>(User.class),username,password);
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		if(user!=null){
			response.getWriter().write("login.success!");
		}else{
			response.getWriter().write("login.failed");
		}
	}

}

4.db.properties的配置文件在src下面创建一个Floader的resource的文件夹。

数据库的名字、密码、用户名要更改，不要乱加空格，容易出错

driverClassName=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/store_db?rewriteBatchedStatements=true
username=root
password=123456
maxActive=8

5.lib的下面放三个jar并且buildpath

链接：https://pan.baidu.com/s/1QPUxvmFTtQeCp4uWDYOfTA
提取码：35mq
6.web.xml的内容，要是创建动态的web项目可有可无。这里面不放了

7.html页面

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<h1>登录界面</h1>
<form action="http://localhost:8081/Login_dbutils/login" method="post">
	用 户:<input type="text" placeholder="请输入用户名"  name="username"/><br/><br/>
	密 码:<input type="password" placeholder="请输入密码"  name="password"/><br/><br/>
	<input type="submit" value="登录" />
</form>
</body>
</html>