java-線程池序號一直增加

下午在調試多線程時發現，雖然確認每次都是將線程池關閉

executor.shutdown();
executor.awaitTermination(1, TimeUnit.SECONDS)

可是第二個調用任務進來線程池序號仍是增長了，沒找到緣由。當時想了兩種解決方法，第一種是用spring來管理線程池，第二種是使用單列模式。看了下網上關於使用spring管理線程池的代碼，考慮到我這個功能並無這麼重量級，須要改配置文件來處理。簡單處理，使用單列模式作。

1.建立自定義名稱的線程池

package com.demo.thread.test20170811;

import java.util.concurrent.BlockingQueue;
import java.util.concurrent.RejectedExecutionHandler;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

/**
 * 自定義名稱線程池
 * @author fsw
 *
 */
public class NamedThreadPoolExecutor extends ThreadPoolExecutor{
	
	private String name;

	public NamedThreadPoolExecutor(int corePoolSize, int maximumPoolSize,
			long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue, RejectedExecutionHandler handler) {
		super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue, handler);
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	
}

2.建立單列模式

package com.demo.thread.test20170811;

import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.RejectedExecutionHandler;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.ReentrantLock;

/**
 * 線程池管理類
 * @author fsw
 *
 */
public class SingletonThreadPool {

	final NamedThreadPoolExecutor executor = new NamedThreadPoolExecutor(5,5,0,TimeUnit.SECONDS,new ArrayBlockingQueue<Runnable>(5), new RejectedExecutionHandler() {
		
		@Override
		public void rejectedExecution(Runnable r, ThreadPoolExecutor executor) {
			NamedThreadPoolExecutor namedThreadPoolExe = (NamedThreadPoolExecutor) executor;
			try {
				System.out.println(namedThreadPoolExe.getName());
				executor.getQueue().put(r);
			} catch (Exception e) {
			}
		}
	});

	private static SingletonThreadPool threadPool = null;
	private static ReentrantLock lock =  new ReentrantLock();
	
	public static SingletonThreadPool getInstance() {
		try {
			lock.lock();
			if(threadPool == null) {
				threadPool = new SingletonThreadPool();
				return threadPool;
			}
		} finally {
			lock.unlock();
		}
		return threadPool;
	}
	
	public ExecutorService getExecutorService(String name) {
		executor.setName(name);
		return executor;
	}
	
	public Long getComTaskCount() {
		return executor.getCompletedTaskCount();
	}
}

3.建立執行任務類

package com.demo.thread.test20170811;

import java.util.concurrent.Callable;

public class Task implements Callable<Void>{

	@Override
	public Void call() throws Exception {
		System.out.println(Thread.currentThread().getName());
		return null;
	}

}

4.測試類

package com.demo.thread.test20170811;

import java.util.concurrent.CompletionService;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorCompletionService;

public class SingletonThreadMain {

	public static void main(String[] args) throws InterruptedException, ExecutionException {
		final SingletonThreadMain m = new SingletonThreadMain();
		m.runMethod("a");
		m.runMethod("b");
		m.runMethod("c");
	}

	public void runMethod(final String name) throws InterruptedException, ExecutionException {
		SingletonThreadPool threadPool = SingletonThreadPool.getInstance();
		CompletionService<Void> completionService = new ExecutorCompletionService<Void>(
				threadPool.getExecutorService(name));
		for (int i = 0; i < 100; i++) {
			completionService.submit(new Task());
		}
		
		for (int i = 0; i < 100; i++) {
			completionService.take().get();
		}
		
		System.out.println("==================="+SingletonThreadPool.getInstance().getComTaskCount());
	}
}

5.執行結果

從執行結果可見，線程池序號一直都是1。問題初步解決，後面遇到問題再更新