Guava并发

Guava确实很强大，这次来说下他的并发，主要涉及到的类是：ListenableFuture，顾名思义就是可见听的future，他是对jdk中future的封装，使得此功能代码更简单，实现并发功能更为方便强大，下面直接上代码：

package com.google.guava.test.concorrent;

import java.util.concurrent.Callable;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import com.google.common.util.concurrent.FutureCallback;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.ListenableFuture;
import com.google.common.util.concurrent.ListeningExecutorService;
import com.google.common.util.concurrent.MoreExecutors;
import com.google.common.util.concurrent.RateLimiter;

public class ListenableFutureTest {

	public static void main(String[] args) throws Exception {
		testListenableFuture();
	}
	
	public static void testListenableFuture() throws Exception {
		//通过装饰器模式获取服务
		ListeningExecutorService les = MoreExecutors.listeningDecorator(Executors.newCachedThreadPool());
		
		//此处还可以处理并发访问的线程数
		//每秒不超过5个任务被提交
		RateLimiter rl = RateLimiter.create(5);
		//超过线程数会被堵塞
		rl.acquire();
		
		ListenableFuture<String> lf = les.submit(new Callable<String>() {
			@Override
			public String call() throws Exception {
				TimeUnit.SECONDS.sleep(5);
				return "test";
			}
		});
		//同步获取结果
		System.out.println(lf.get());
		Futures.addCallback(lf, new FutureCallback<String>() {
			@Override
			public void onSuccess(String result) {
				System.out.println(result);
			}
			@Override
			public void onFailure(Throwable t) {
			}
		});
	}

}