Eclipse三层架构项目(增删改查)

搭建好项目记得导包：

连接池(根据自己的配置改)：

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/student?useUnicode=true&characterEncoding=utf-8&useSSL=false
user=root
password=994994

连接数据库工具类：

package com.accp.dao;

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

public class BaseDao {
	private static String driver;
	private static String url;
	private static String user;
	private static String password;
	private Connection conn;
	private PreparedStatement pstmt;
	private ResultSet rs;
	
	static {
		Properties params = new Properties();
		String configFile = "database.properties";
		InputStream is = BaseDao.class.getClassLoader().getResourceAsStream(configFile);
		try {
			params.load(is);
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		driver=params.getProperty("driver");
		url=params.getProperty("url");
		user=params.getProperty("user");
		password=params.getProperty("password");
	}
	
    //连接
	public Connection getConnection() {
		try {
			Class.forName(driver);
			conn = DriverManager.getConnection(url, user, password);
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return conn;
	}

    //关闭流
	public void closeAll() {
		if (null != rs) {
			try {
				rs.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		if (null != pstmt) {
			try {
				pstmt.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		if (null != conn) {
			try {
				conn.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}

    //增删改
	public int executeUpdate(String sql, Object... objects) {
		getConnection();
		int rows = 0;
		try {
			pstmt = conn.prepareStatement(sql);
			for (int i = 0; i < objects.length; i++) {
				pstmt.setObject(i + 1, objects[i]);
			}
			rows = pstmt.executeUpdate();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} finally {
			closeAll();
		}
		return rows;
	}

    //查询
	public ResultSet executeQuery(String sql, List