Java连接数据库实现用户登录密码验证

﹏ヽ暗。殇╰゛Y 2022-02-04 13:41 396阅读 2赞

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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>

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