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下面通过一个简单的样例来说明如何利用apache common pool来应用对象池。

假定我现在有一个任务，就是对一堆字符串进行格式化，为了加快速度，采用了多线程的方式允许，而格式化则是通过对象StringFormat来实现。

采用池技术，目的在于循环利用此对象，避免不停的生成和回收类。

也许本样例并不是很恰当，但是如何StringFormat换成是数据库连接就非常适合池技术了，此样例仅用于说明如何使用apache common pool池而已。

字符串格式化类：

public class StringFormat {	public String format(String str)	{		return "formated:"+str;	}}

对象工厂：

import org.apache.commons.pool2.BasePooledObjectFactory;import org.apache.commons.pool2.PooledObject;import org.apache.commons.pool2.impl.DefaultPooledObject;public class StringFormatFactory    extends BasePooledObjectFactory
   
     {    @Override    public StringFormat create() {    	System.out.println("create object");        return new StringFormat();    }    /**     * Use the default PooledObject implementation.     */    @Override    public PooledObject
    
      wrap(StringFormat buffer) {        return new DefaultPooledObject
     
      (buffer);    }    /**     * When an object is returned to the pool, clear the buffer.     */    @Override    public void passivateObject(PooledObject
      
        pooledObject) {    	System.out.println("Object been returned to pool");    }    // for all other methods, the no-op implementation    // in BasePooledObjectFactory will suffice}
      
     
    
   

处理线程类：

import org.apache.commons.pool2.ObjectPool;public class StringProcessThread extends Thread {	private ObjectPool
   
     pool;	private String toProcessStr;	public StringProcessThread(ObjectPool
    
      pool,			String toProcessStr) {		this.pool = pool;		this.toProcessStr = toProcessStr;	}	public void run() {		StringFormat stringFormat = null;		try {			stringFormat = pool.borrowObject();			String formattedStr = stringFormat.format(toProcessStr);			System.out.println(formattedStr);		} catch (Exception e) {			e.printStackTrace();		} finally {			try {				if (stringFormat != null) {					pool.returnObject(stringFormat);				}			} catch (Exception e) {				e.printStackTrace();			}		}	}}
    
   

主程序：

import java.io.IOException;import java.io.Reader;import java.util.ArrayList;import java.util.List;import org.apache.commons.pool2.ObjectPool;import org.apache.commons.pool2.impl.GenericObjectPool;public class StringProcessor {	private ObjectPool
   
     pool;	public StringProcessor(ObjectPool
    
      pool) {		this.pool = pool;	}	/**	 * Dumps the contents of the {@link Reader} to a String, closing the	 * {@link Reader} when done.	 */	public void process(List
     
       strList) {		for (String str : strList) {			Thread thread = new StringProcessThread(pool, str);			thread.start();		}				//设置等待两秒，等待线程结束		try {			Thread.sleep(2000);		} catch (InterruptedException e) {			e.printStackTrace();		}	}	public static void main(String[] args) throws IOException {		StringProcessor stringProcessor = new StringProcessor(				new GenericObjectPool
      
       (new StringFormatFactory()));		List
       
         strList = new ArrayList
        
         (); strList.add("123"); strList.add("456"); strList.add("789"); stringProcessor.process(strList); }}
        
       
      
     
    
   

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