JDBC连结池程序

这个是连结池

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Properties;


public class ConnectionPool {
	private ArrayList<Connection> pool;
	private String username;
	private String password;
	private String driverClassName;
	private String url;
	private int poolSize = 1;
	private static ConnectionPool instance = null;
	//构造方法
	private ConnectionPool(){
		init();
	}
	//初始化
	private void init(){
		pool = new ArrayList<Connection>(poolSize);
		//读取配置文件
		readConfig();
		//创建Connection实例到pool
		addConnection();
	}
	//读取配置文件
	private void readConfig(){		
		try {
			//取得当前主机存放项目的绝对路径
			String path = System.getProperty("user.dir")+"\\dbpool.properties";
			//读取文件
			FileInputStream fis = new FileInputStream(path);
			//建立属性文件
			Properties ps = new Properties();
			ps.load(fis);
			//getProperty(String name)获得配置文件信息
			this.driverClassName = ps.getProperty("driverClassName");
			this.username = ps.getProperty("username");
			this.password = ps.getProperty("password");
			this.url = ps.getProperty("url");
			this.poolSize = Integer.parseInt(ps.getProperty("poolSize"));			
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}		
	}
	//创建Connection实例到pool
	private void addConnection(){
		Connection conn = null;
		try {
			Class.forName(driverClassName);		
			for(int i=0;i<this.poolSize;i++){				
					conn = java.sql.DriverManager.getConnection(url, username, password);
					pool.add(conn);
			}
		} catch (SQLException e) {
			e.printStackTrace();
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}
	}
	//获得连结池的实例，单例模式
	public static ConnectionPool getConnectionPool(){
		if(instance==null){
			instance = new ConnectionPool();			
		}
		return instance;
	}
	//从pool获得一个Connection
	public synchronized Connection getConnection(){
		if(pool.size()>0){
			Connection conn = pool.get(0);
			pool.remove(conn);
			return conn;
		}
		return null;
	}
	//使用完成Connection之后又放回pool
	public synchronized void release(Connection conn){
		pool.add(conn);
	}
	//关闭连结池里的conn
	public synchronized void close(){
		Connection conn;
		try {
			for(int i=0;i<pool.size();i++){
				conn = pool.get(i);			
				conn.close();
				pool.remove(i);
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}
}

配置文件dbpool.properties

driverClassName=com.mysql.jdbc.Driver
username=root
password=password
url=jdbc:mysql://localhost:3306/mydata
poolSize=10

测试程序

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


public class ConnectionPoolTest {
	private static String sql = "select * from user";
	public static void main(String[] args) throws SQLException, ClassNotFoundException {
		long start = System.currentTimeMillis();
		Connection conn = null;
		ConnectionPool pool = null;
		Statement sta = null;
		ResultSet rs = null;
		for(int i=0;i<1000;i++){
			pool = ConnectionPool.getConnectionPool();
			conn = pool.getConnection();
			sta = conn.createStatement();
			rs = sta.executeQuery(sql);
			while(rs.next()){
				
			}
			rs.close();
			sta.close();
			pool.release(conn);
		}
		pool.close();
		System.out.println("pool connection time:"+(System.currentTimeMillis()-start));
		start = System.currentTimeMillis();
		for(int i=0;i<1000;i++){
			Class.forName("com.mysql.jdbc.Driver");
			conn = java.sql.DriverManager.getConnection("jdbc:mysql://localhost:3306/mydata", "root", "password");
			sta = conn.createStatement();
			rs = sta.executeQuery(sql); 
			while(rs.next()){
				
			}
			rs.close();
			sta.close();
			conn.close();
		}
		System.out.println("not use pool connection time:"+(System.currentTimeMillis()-start));
		
	}

}

pool connection time:3304
not use pool connection time:32527