JAVA并发- 典型连接池的实现

package com.xyz.connpool;public interface IConnection {/** * 关闭当前连接 */public void close();/** * 销毁当前连接 */public void destroy();//应该具备的其他方法}

public class Connection implements IConnection {private String name;private IConnPool connPool;public Connection(IConnPool connPool,String name){this.connPool=connPool;this.name=name;}@Overridepublic void close() {this.connPool.releaseConn(this);}@Overridepublic void destroy() {System.out.println("destroy connection---"+name);}@Overridepublic String toString() {// TODO Auto-generated method stubsuper.toString();return name;}}

public interface IConnPool { /**  * 获得一个可用连接，超过最大连接数时线程等待，直到有有连接释放时返回一个可用连接或者超时返回null   * @param maxWaitTime  * @return  */public IConnection getConn();/** * 将释放的空闲连接加入空闲连接池 * @param conn */public void releaseConn(IConnection conn);/** * 销毁连接池 */public void destroy();/** * 获取当前线程对应的连接 * @return */public IConnection getCurrentConn();}

import java.util.ArrayList;import java.util.List;import java.util.UUID;public class ConnPool implements IConnPool {private int initNum;private int maxNum;private int hasAlready;private long maxWaitTime;private final List<IConnection> freeConnList;private final List<IConnection> activeConnList;private static ThreadLocal<IConnection> threadLocalVar=new ThreadLocal<IConnection>(){protected IConnection initialValue() {return null;};};public ConnPool(){this.initNum=3;this.maxNum=5;this.hasAlready=0;this.maxWaitTime=1000;this.freeConnList=new ArrayList<IConnection>(maxNum);this.activeConnList=new ArrayList<IConnection>(maxNum);init();}public ConnPool(int initNum,int maxNum,long maxWaitTime){this.initNum=initNum;this.maxNum=maxNum;this.hasAlready=0;this.maxWaitTime=maxWaitTime;this.freeConnList=new ArrayList<IConnection>(maxNum);this.activeConnList=new ArrayList<IConnection>(maxNum);init();}private void init(){for(int i=0;i<this.initNum;i++){synchronized (this) {this.freeConnList.add(new Connection(this,UUID.randomUUID().toString()));hasAlready++;}}}@Overridepublic synchronized IConnection getConn()  {IConnection conn=null;if(!this.freeConnList.isEmpty()){conn=this.freeConnList.remove(0);if(conn!=null)threadLocalVar.set(conn);//为线程绑定连接this.activeConnList.add(conn);return conn;}if(hasAlready<maxNum){conn = new Connection(this,UUID.randomUUID().toString());hasAlready++;if(conn!=null)threadLocalVar.set(conn);//为线程绑定连接this.activeConnList.add(conn);return conn;}try {this.wait(maxWaitTime);if(!this.freeConnList.isEmpty()){conn=this.freeConnList.remove(0);if(conn!=null)threadLocalVar.set(conn);//为线程绑定连接this.activeConnList.add(conn);return conn;}return null;} catch (InterruptedException e) {e.printStackTrace();return null;}}@Overridepublic synchronized void releaseConn(IConnection conn) {if(this.activeConnList.contains(conn)){this.freeConnList.add(conn);this.activeConnList.remove(conn);threadLocalVar.remove();this.notify();                 }}@Overridepublic synchronized void destroy() {IConnection conn=null;int temp=this.freeConnList.size();for(int i=0;i<temp;i++){conn=this.freeConnList.remove(0);conn.destroy();}temp=this.activeConnList.size();for(int i=0;i<temp;i++){conn=this.activeConnList.remove(0);conn.destroy();}conn=null;this.hasAlready=0;}         @Overridepublic IConnection getCurrentConn() {return threadLocalVar.get();}}

package com.xyz.connpool;import java.util.Map;import java.util.concurrent.ConcurrentHashMap;public class ConnPoolManager {private int initConnNum;private int maxConnNum;private long maxWaitTime;// 连接池存放public Map<Integer,IConnPool> pools=new ConcurrentHashMap<Integer, IConnPool>();//public Hashtable<Integer,IConnPool> pools = new Hashtable<Integer, IConnPool>();public ConnPoolManager(int initConnNum,int maxConnNum, long maxWaitTime){this.initConnNum=initConnNum;this.maxConnNum=maxConnNum;this.maxWaitTime=maxWaitTime;init();}// 初始化所有的连接池private void init(){for(int hostId =0;hostId<3;hostId++){ConnPool connPool=new ConnPool(this.initConnNum,this.maxConnNum, this.maxWaitTime);if(connPool != null){pools.put(hostId,connPool);System.out.println("Info:Init connPool successed for hostId ->" +hostId);}}}/** * 根据主机id获取连接池 * @param hostId * @return */public IConnPool getPool(int hostId){IConnPool pool = null;if(pools.containsKey(hostId)){ pool = pools.get(hostId);}return pool;}/** * 获取一个到主机hostId的连接 * @param hostId * @return */public IConnection getConn(int hostId){IConnPool connPool = getPool(hostId);if(connPool==null){System.out.println("Error:Can't find this connecion pool for hostId->"+hostId);return null;}return connPool.getConn();}/** * 关闭指定主机的某个链接 * @param hostId * @param conn */public void close(int hostId,IConnection conn){IConnPool pool = getPool(hostId);if(pool != null)pool.releaseConn(conn);}/** * 注销某个主机的连接池 * @param poolName */public void destroy(int hostId){IConnPool pool = getPool(hostId);if(pool != null){pool.destroy();}pools.remove(pool);}/** * 注销所有连接池 */public void destory(){for(int hostId:pools.keySet()){this.destroy(hostId);}}}

package com.xyz.connpool;import java.util.concurrent.CountDownLatch;public class Demo {public final static int REQUESTNUM=200;public final static int DURATION=20; public static void main(String [] args) throws Exception{final CountDownLatch startGate=new CountDownLatch(1);final CountDownLatch endGate=new CountDownLatch(REQUESTNUM);final ConnPoolManager cpm=new ConnPoolManager(5, 10, 1000);final IConnection conns[] =new IConnection[REQUESTNUM];for(int i=0;i<REQUESTNUM;i++){final int flag=i;new Thread(new Runnable() {@Overridepublic void run() {try {startGate.await();} catch (InterruptedException e1) {}conns[flag]=cpm.getConn(0);System.out.println(conns[flag]);try {Thread.sleep(DURATION);} catch (InterruptedException e) {}cpm.close(0, conns[flag]);endGate.countDown();}}).start();}long begin = System.currentTimeMillis();startGate.countDown();endGate.await();long over = System.currentTimeMillis();System.out.println(over-begin);//    Thread.sleep(5000);    cpm.destory();}}

源代码下载https://github.com/ZhenShiErGe/ConnectionPool.git