C3P0连接池和Druid连接池

C3P0数据连接池:

所需要导入jar包:

package utils;

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

import javax.sql.DataSource;

import com.mchange.v2.c3p0.ComboPooledDataSource;

public class C3P0Utils {
	//创建数据源对象
	private static ComboPooledDataSource dataSource = new ComboPooledDataSource();
	
	//获取数据连接对象
	public static Connection getConnection() throws SQLException{
		return dataSource.getConnection();
	} 
	
	//关闭数据连接
	public static void closeAll(Connection conn,Statement stmt,ResultSet rs){
		if(rs!=null){
			try {
				rs.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
		if(stmt!=null){
			try {
				stmt.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
		if(conn!=null){
			try {
				conn.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
	}
	//获取数据源
	public static DataSource getDateSource(){
		return dataSource;
	}
}

C3P0-config.xml

	
	
		jdbc:mysql://localhost:3306/db1
		com.mysql.jdbc.Driver
		root
		root
		30000
		10
		30
		100
		10
	
	
	
		jdbc:mysql://localhost:3306/db1
		com.mysql.jdbc.Driver
		root
		root
		30000
		10
		30
		100
		10
	
	
	
		jdbc:mysql://localhost:3306/db1
		com.mysql.jdbc.Driver
		root
		root
		30000
		10
		30
		100
		10
	

Druid数据连接池:

所需jar包:

package com.igeekhome.igeekshop.util;

import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;

import javax.sql.DataSource;

import com.alibaba.druid.pool.DruidDataSource;

public class DBUtil {
	private static DruidDataSource ds;

	private static ThreadLocal connection = new ThreadLocal<>();
	static {
		Properties prop = PropertiesUtil.loadProperties("jdbc.properties");
		ds = new DruidDataSource();
		ds.setDriverClassName(prop.getProperty("druid.driverClass"));
		ds.setUrl(prop.getProperty("druid.jdbcUrl"));
		ds.setUsername(prop.getProperty("druid.user"));
		ds.setPassword(prop.getProperty("druid.password"));
	}

	private DBUtil() {

	}

	public static DataSource getDs() {
		return ds;
	}

	public static Connection getConnection() throws SQLException {
		// 先从ThreadLocal中获取连接对象
		Connection con = connection.get();
		// 1.如果有，则直接返回
		if (con != null) {
			return con;
		}
		// 2.如果没有，则从连接池中获取一个新的连接对象，并将该连接对象存入ThreadLocal中
		else {
			con = ds.getConnection();
			connection.set(con);
			return con;
		}
	}

	public static void close(Connection con) {
		if (con != null) {
			try {
				con.close();
				connection.set(null);
			} catch (SQLException e) {
			}
		}
	}
}

读取properties文件的工具类:

package com.igeekhome.igeekshop.util;

import java.io.IOException;
import java.util.Properties;

public class PropertiesUtil {
	private PropertiesUtil() {

	}

	public static Properties loadProperties(String fileName) {
		Properties prop = new Properties();
		try {
			prop.load(PropertiesUtil.class.getClassLoader().getResourceAsStream(fileName));
		} catch (IOException e) {
			e.printStackTrace();
		}
		return prop;
	}

}

jdbc.properties

druid.driverClass=com.mysql.jdbc.Driver
druid.jdbcUrl=jdbc:mysql://localhost:3306/igeekshop
druid.user=root
druid.password=root

总结：由于在Spring项目中，C3P0会有几率出现死锁的现象，所以我还是比较倾向于阿里巴巴开发的Druid来连接数据库。至于死锁现象，是存在线程同时占用两个连接对象的问题。