对象池

import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;



public class ObjectPool {
	
	private int objectNum = 100;	//对象总数
	
	private Class c = TestObject.class;	//当前对象类型
	private List<Object> avaiObjects; // 空闲对象集合
	private List<Object> objects;	//总对象集合
	private static ObjectPool objectPool;
	
	private long timeOut = 2000;
	private boolean flag;	//是否已经初始化了
	private ObjectPool(){
		//init
		if(objectNum > 0){
			avaiObjects = new LinkedList<Object>();
			
			objects = new ArrayList<Object>();
			Object object = null;
			for(int i = 0 ; i < objectNum ; i++){
				try {
					object = c.newInstance();
					avaiObjects.add(object);
					objects.add(object);
					
					object = null;
				} catch (Exception e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				} 
			}
			flag = true;
			System.out.println("程序初始化完成，max=" + objectNum + ",class=" + c );
		}else {
			throw new RuntimeException("对象数目不可小于0");
		}
		
	}
	
	public static synchronized ObjectPool getInstance(){
		if(objectPool == null)
			objectPool = new ObjectPool();
		return objectPool;
	}
	
	/**
	 * 得到一个可用的对象
	 * @return
	 */
	public Object getAviObject(){
		
		Object object = getObject();
		if(object == null){
			try {
				System.out.println("等待");
				Thread.currentThread().sleep(timeOut);
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			object = getObject();
			
		}
		return object;

		
	}
	
	/**
	 * 归还一个已经用完的对象
	 * @return
	 */
	public synchronized boolean closeObject(Object object , String name){
		
		if(object != null){
			avaiObjects.add(object);
			System.out.println(name + "归还："+avaiObjects.size());
		}else {
			System.out.println(name + "归还null："+avaiObjects.size());
		}
		return false;
	}

	public synchronized Object getObject(){
		
		if(avaiObjects.size() > 0){
			try {
				System.out.println("外借："+avaiObjects.size());
				return avaiObjects.get(0);
			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}finally{
				avaiObjects.remove(0);
				
			}
		}else{
			System.err.println("无可用对象");

		}
		return null;
	}
	public synchronized int aviObjectCount(){
		return avaiObjects.size();
	}
}

import java.util.Random;



public class Test {
	private static int count=0;
	public static void main(String[] args) {
		for (int i = 0; i < 1000; i++) {
			
			new Thread(new Runnable() {
				
				public void run() {
					int time = 300;
					String name = Test.get();
					while (true) {
						System.out.println("活跃线程："+Thread.activeCount());
						TestObject testObject = (TestObject)ObjectPool.getInstance().getAviObject();
						if(testObject == null)
							continue;
						
						try {
							System.out.println(name + "休眠" + time);
							Thread.currentThread().sleep(time);
							//if(time <2000)
								//time +=300;
							System.out.println(name + "醒来");
						} catch (InterruptedException e) {
							// TODO Auto-generated catch block
							e.printStackTrace();
						}
						testObject.println(name);
						ObjectPool.getInstance().closeObject(testObject , name);
						
						try {
							
							Thread.currentThread().sleep(new Random().nextInt(3000));
						} catch (InterruptedException e) {
							// TODO Auto-generated catch block
							e.printStackTrace();
						}
						
					}
					
				}
			} , "test").start();
			
			
		}
		
	}
	
	public static synchronized String get(){
		return "线程" + count++;
	}

}

public class TestObject {
	
	public void println(String s){
		System.out.println(s);
	}

}

评论

2 楼 zhouqiugang 2011-08-24  

while true 

1 楼 zhouqiugang 2011-08-24  

怎么循环1000，但是我运行下Test，线程一直在跑。像是死循环。