【Java 多线程 1】CountDownLatch

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ge com.guor.threads;

import java.text.SimpleDateFormat;

import java.util.ArrayList;

import java.util.Date;

import java.util.List;

import java.util.concurrent.Callable;

import java.util.concurrent.CountDownLatch;

import java.util.concurrent.ExecutionException;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Executors;

import java.util.concurrent.Future;

import java.util.concurrent.TimeUnit;

public class CountDownLatchDemo implements Callable<Integer>{

static int threadCount = 15;

static int awaitMillisecond = 3000;

static CountDownLatch countDownLatch = new CountDownLatch(threadCount);

int id;

public CountDownLatchDemo(int id) {

this.id = id;

}

public static void main(String[] args) throws InterruptedException, ExecutionException {

boolean fireFlag = true;

ExecutorService newFixedThreadPool = Executors.newFixedThreadPool(threadCount);

List<Future<Integer>> futureList = new ArrayList<Future<Integer>>();

for(int i = 0; i< threadCount; i++) {

Future<Integer> future = newFixedThreadPool.submit(new CountDownLatchDemo(i));

futureList.add(future);

}

for(int i = 0; i< threadCount; i++) {

Future<Integer> future = futureList.get(i);

if(0 == future.get()) {

fireFlag = false;

break;

}

}

if(true == fireFlag) {

System.out.println(getCurrentTime() + "fire.");

}else {

System.out.println(getCurrentTime() + "countDownLatch.await().");

//设置超时时间 awaitMillisecond

countDownLatch.await(awaitMillisecond, TimeUnit.MILLISECONDS);

System.out.println(getCurrentTime() + Thread.currentThread().getName() + ", 线程阻塞");

//线程阻塞

countDownLatch.await();

System.out.println(getCurrentTime() + "thread contains error, do not fire.");

}

newFixedThreadPool.shutdown();

}

@Override

public Integer call() {

try {

if(id < 9) {

System.out.println(getCurrentTime() + Thread.currentThread().getName()+", 检查完毕.");

countDownLatch.countDown();

return 1;

}else {

//int a = 1/0;

System.out.println(getCurrentTime() + Thread.currentThread().getName()+", 存在异常，检查中...");

Thread.sleep(awaitMillisecond);

System.out.println(getCurrentTime() + Thread.currentThread().getName()+", 检查失败.");

return 0;

}

}catch (Exception e) {

System.out.println("call exception.");

return 0;

}

}

private static String getCurrentTime() {

Date date = new Date();

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");

String format = sdf.format(date);

String ret = "[" + format + "] ";

return ret;

}

}

?2、控制台输出

（1）发射成功

（2）发射失败