JDBC_DAO模式

包结构

---

• src
  • dao
    • UserDao.java
  • dao.impl
    • UserDaoimpl.java
  • util
    • JDBCUtil.java
  • test
    • Test.java
  • jdbc.properties.txt
• lib
  • mysql-connector-java-bin.jar

---

完整代码

jdbc.properties

#mysql
driverClass = com.mysql.jdbc.Driver
url = jdbc:mysql://localhost:3306/emp
user = root
password = 1230

#oracl
#driver = oracle.jdbc.driver.OracleDriver
#jdbcUrl = jdbc:oracle:thin:@localhost:1521:orcl
#user = root
#password = 1230

JDBCUtil.java

package util;

import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import  java.sql.Statement;
import java.util.Properties;


public class JDBCUtil {

	static String driverClass= null;
	static String url = null;
	static String user = null;
	static String password = null;
	
	static {
		try {
			//创建一个属性配置对象
			Properties properties = new Properties();
			//根工程目录
//			InputStream in = new FileInputStream("jdbc.properties");
			//src路径
			//使用类加载器，读取配置文件
			InputStream in = JDBCUtil.class.getClassLoader().getResourceAsStream("jdbc.properties");
			//输入流
			properties.load(in);
			
			driverClass = properties.getProperty("driverClass");
			url = properties.getProperty("url");
			user = properties.getProperty("user");
			password = properties.getProperty("password");
			
		} catch (IOException e) {
			e.printStackTrace();
		}
	
	}
	
	public static Connection getConn() {
		Connection conn = null;
		
		try {
			//4.0以上版本不用注册驱动
			//Class.forName(driverClass);
			conn = DriverManager.getConnection(url, user, password);
			
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
		return conn;
	}
	
	
	/**
	 * 释放资源
	 * @param conn
	 * @param st
	 */
	public static void release(Connection conn, Statement st, ResultSet rs) {
		closeRs(rs);
		closeSt(st);
		closeConn(conn);
	}
	
	public static void release(Connection conn, Statement st) {
		
		closeSt(st);
		closeConn(conn);
	}
	
	public static void closeRs(ResultSet rs) {
		try {
			if(rs != null) {
				rs.close();
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}finally {
			rs=null;
		}
	}
	
	public static void closeSt(Statement st) {
		try {
			if(st != null) {
				st.close();
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}finally {
			st=null;
		}
	}
	
	public static void closeConn(Connection conn) {
		try {
			if(conn != null) {
				conn.close();
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}finally {
			conn=null;
		}
	}
}

UserDao.java

package dao;

public interface UserDao {

	/**
	 * 根据id去更新具体的用户名
	 * @param id
	 * @param name
	 */
	void update(int id , String name);
	
	void delete(int id);
	
	/**
	 * 执行添加
	 * @param userName
	 * @param password
	 */
	void insert(String userName , String password);
	
	/**
	 * 查询所有
	 */
	void findAll();
	
	
	/**
	 * 登录方法
	 * @param username
	 * @param password
	 */
	void login(String username , String password);
}

UserDaoImpl.java

package dao.impl;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.PreparedStatement;

import dao.UserDao;
import util.JDBCUtil;

public class UserDaoImpl  implements UserDao{
	
	/**
	 * 查询所有
	 */
	@Override
	public void findAll() {
		Connection conn = null;
		Statement st = null;
		ResultSet rs = null;
		try {
			//1. 创建连接对象
			conn = JDBCUtil.getConn();
			
			//2. 创建statement对象
			st = conn.createStatement();
			
			String sql="select * from tt";
			rs = st.executeQuery(sql);
			
			while(rs.next()){
				String name = rs.getString("name");
				String age = rs.getString("age");
				
				System.out.println(name+":"+age);
			}
			
		} catch (SQLException e) {
			e.printStackTrace();
		}finally {
			JDBCUtil.release(conn, st, rs);
		}
	}
	
	/**
	 * 登陆校验
	 */
	/*@Override
	public void login(String username, String password) {
		
		Connection conn = null;
		Statement st = null;
		ResultSet rs = null;
		try {
			//1. 获取连接对象
			conn = JDBCUtil.getConn();
			//2. 创建statement对象
			st = conn.createStatement();
//			SELECT * FROM t_user WHERE username='admin' AND PASSWORD='10086'
			String sql = "select * from t_user where username='"+ username  +"' and password='"+ or +"'";
			rs = st.executeQuery(sql);
			
			if(rs.next()){
				System.out.println("登录成功");
			}else{
				System.out.println("登录失败");
			}
			
		} catch (Exception e) {
			e.printStackTrace();
		}finally {
			JDBCUtil.release(conn, st, rs);
		}
	}*/
	
	
	/**
	 * 登陆校验
	 */
	@Override
	public void login(String username,String password) {
		
		Connection conn = null;
		Statement st = null;
		ResultSet rs = null;
		PreparedStatement ps = null;
		String sql = "";
		
		try {
			conn = JDBCUtil.getConn();
//			st = conn.createStatement();
			//2.预先对sql语句执行语法校验， ？ 对应的内容，后面不管什么传递进来，都当做字符串
			sql = "select * from login where username=? and password=?";
			ps = conn.prepareStatement(sql);
			
			// ? 索引从1开始
			ps.setString(1, username);
			ps.setString(2, password);
			
			rs = ps.executeQuery();
			
			if(rs.next()) {
				System.out.println("登陆成功");
			}else {
				System.out.println("登陆失败");
			}
			
		} catch (SQLException e) {
			e.printStackTrace();
		}finally {
			JDBCUtil.release(conn, st, rs);
		}
	}
	
	/**
	 * 插入
	 */
	@Override
	public void insert(String username, String password) {
		
		Connection conn = null;
		Statement st = null;
		PreparedStatement ps = null;

		String sql = "";
		
		try {
			conn = JDBCUtil.getConn();
			
			sql = "insert into tt values(4 , ? , ?)";
//			st = conn.createStatement();
			//2.预先对sql语句执行语法校验， ？ 对应的内容，后面不管什么传递进来，都当做字符串
			ps = conn.prepareStatement(sql);
			
			//?索引从1开始
			ps.setString(1, username);
			ps.setString(2, password);
			
			int result = ps.executeUpdate();
			
			if(result>0) {
				System.out.println("插入成功");
			}else {
				System.out.println("插入失败");
			}
			
		} catch (SQLException e) {
			e.printStackTrace();
		}finally {
			JDBCUtil.release(conn, ps);
		}
	}
	
	/**
	 * 删除
	 */
	@Override
	public void delete(int id) {

		Connection conn = null;
		PreparedStatement ps = null;

		String sql = "";
		
		try {
			conn = JDBCUtil.getConn();
			
			sql = "delete from tt where id=?";
//			st = conn.createStatement();
			//2.预先对sql语句执行语法校验， ？ 对应的内容，后面不管什么传递进来，都当做字符串
			ps = conn.prepareStatement(sql);
			
			//?索引从 1 开始
			ps.setInt(1, id);
			
			int result = ps.executeUpdate();
			
			if(result>0) {
				System.out.println("删除成功");
			}else {
				System.out.println("删除失败");
			}
			
		} catch (SQLException e) {
			e.printStackTrace();
		}finally {
			JDBCUtil.release(conn, ps);
		}
	}
	
	/**
	 * 更新
	 */
	@Override
	public void update(int id, String name) {

		Connection conn = null;
		PreparedStatement ps = null;

		String sql = "";
		
		try {
			conn = JDBCUtil.getConn();
			
			sql = "update tt set id=? where name=?";
//			st = conn.createStatement();
			//2.预先对sql语句执行语法校验， ？ 对应的内容，后面不管什么传递进来，都当做字符串
			ps = conn.prepareStatement(sql);
			
			//?索引从1开始
			ps.setInt(1, id);
			ps.setString(2, name);
			
			int result = ps.executeUpdate();
			
			if(result>0) {
				System.out.println("更新成功");
			}else {
				System.out.println("更新失败");
			}
			
		} catch (SQLException e) {
			e.printStackTrace();
		}finally {
			JDBCUtil.release(conn, ps);
		}
	}
}

Test.java

package test;

import org.junit.Test;

import dao.UserDao;
import dao.impl.UserDaoImpl;

public class TestUserDaoImpl {

	
	@Test
	public void testFindAll(){
		
		UserDao dao = new UserDaoImpl();
		
		dao.findAll();
	}
	@Test
	public void testlogin(){
		
		UserDao dao = new UserDaoImpl();
		
		dao.login("lishishi", "45612213321");
	}
	
	
	@Test
	public void testInsert(){
		
		UserDao dao = new UserDaoImpl();
		
		dao.insert("wangwuwu","789");
	}
	@Test
	public void testDelete(){
		
		UserDao dao = new UserDaoImpl();
		
		dao.delete(4);
	}
	
	@Test
	public void testUpdate(){
		
		UserDao dao = new UserDaoImpl();
		
		dao.update(99, "gengxin");
	}
	
}