一个DBCP数据库连接工具类

package com.softeem.dbutils;

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

import org.apache.commons.dbcp2.BasicDataSource;

public class DBUtils {

	//连接数据库基本属性
	private static String driverClass;
	private static String url;
	private static String username;
	private static String password;
	//连接池属性
	private static int initSize;
	private static int maxSize;
	private static int maxIdle;
	private static long maxWait;
	//数据源
	private static BasicDataSource bds;
	
	//初始化数据源配置
	static{
		init();
	}
	
	public static void init(){
		try {
			//创建数据源对象
			bds = new BasicDataSource();
			//加载属性文件，获取属性信息
			Properties props = new Properties();
			props.load(DBUtils.class.getResourceAsStream("jdbc.properties"));
			driverClass = props.getProperty("driver");
			url = props.getProperty("url");
			username = props.getProperty("user");
			password = props.getProperty("password");
			
			initSize = Integer.parseInt(props.getProperty("initSize"));
			maxSize = Integer.parseInt(props.getProperty("maxSize"));
			maxIdle = Integer.parseInt(props.getProperty("maxIdle"));
			maxWait = Long.parseLong(props.getProperty("maxWait"));
			
			//设置驱动类路径
			bds.setDriverClassName(driverClass);
			//设置url
			bds.setUrl(url);
			//设置用户名
			bds.setUsername(username);
			//设置密码
			bds.setPassword(password);
			
			//设置初始连接数
			bds.setInitialSize(initSize);
			//设置最大连接
			bds.setMaxTotal(maxSize);
			//设置最大闲置连接数
			bds.setMaxIdle(maxIdle);
			//等待获取连接的最大时间(MS)
			bds.setMaxWaitMillis(maxWait);
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
	
	//获取连接
	public static Connection getConn(){
		try {
			if(bds == null || bds.isClosed()){
				init();
			}
			return bds.getConnection();
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return null;
	}
	
	//封装资源回收的方法
	public static void close(ResultSet rs,Statement stat,Connection conn){
	
		try {
			if(rs != null) rs.close();
			if(stat != null) stat.close();
			if(conn != null)conn.close();
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}
}

//配置文件 jdbc.properties

driver = com.mysql.jdbc.Driver
url = jdbc:mysql://127.0.0.1:3306/mydb
user = root
password = 51301035