JAVA多线程处理for循环数据-编程学习网

对for循环内数据启用多线程执行，主线程与子线程无先后顺序

    public static void main(String[] args) throws InterruptedException {        for (int i = 0; i < 5; i++) {            ThreadUtil.execAsync(() -> {                try {                    Thread.sleep(1000);                } catch (InterruptedException e) {                    e.printStackTrace();                }                System.out.println("线程" + Thread.currentThread().getName() + "执行完");            });            System.out.println("第" + i + "个线程");        }        System.out.println("完成");    }

执行结果：
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对for循环内数据启用多线程执行，主线程在所有子线程执行完成之后执行

    public static void main(String[] args) throws InterruptedException {        //初始化线程数量        CountDownLatch countDownLatch = ThreadUtil.newCountDownLatch(5);        for (int i = 0; i < 5; i++) {            ThreadUtil.execute(() -> {                try {                    Thread.sleep(1000);                } catch (InterruptedException e) {                    e.printStackTrace();                }                System.out.println("线程" + Thread.currentThread().getName() + "执行完");                //调用线程计数器-1                countDownLatch.countDown();            });            System.out.println("第" + i + "个线程");        }        //唤醒主线程        countDownLatch.await();        System.out.println("完成");    }

执行结果：
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对for循环内数据启用多线程执行，主线程在所有子线程执行完成之后执行

 public static void main(String[] args) throws InterruptedException {        // 线程个数        int N = 10;        // 实例化一个倒计数器，N指定计数个数        CountDownLatch countDownLatch = new CountDownLatch(N);        for (int i = 0; i < N; i++) {            new Thread(new Runnable() {                @Override                public void run() {                    try {                        Thread.sleep(5000);                        System.out.println("子线程" + Thread.currentThread().getName() + "休眠结束");                    } catch (Exception e) {                        e.printStackTrace();                    } finally {                    // 计数减一                        countDownLatch.countDown();                     }                }            }).start();        }        // 阻塞，等待当计数减到0时，执行后面的代码        countDownLatch.await();        System.out.println("结束");    }

执行结果：
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4. JAVA多线程10个线程处理1000个数据

    public static void main(String[] args) throws Exception {        List<Integer> idList = new ArrayList<>();        for (int i = 1; i <= 1000; i++) {            idList.add(i);        }        int threadNum = 10;        ExecutorService executorService = Executors.newFixedThreadPool(threadNum);        CountDownLatch countDownLatch = new CountDownLatch(threadNum);        int perSize = idList.size() / threadNum;        // 定义接受数据集合  多线程情况下，使用线程安全集合        List<Integer> resultList = Collections.synchronizedList(new ArrayList());        for (int i = 0; i < threadNum; i++) {            MultiThread thread = new MultiThread();            thread.setIdList(idList.subList(i * perSize, (i + 1) * perSize));            thread.setCountDownLatch(countDownLatch);            thread.setResultList(resultList);            executorService.submit(thread);        }        countDownLatch.await();        executorService.shutdown();        // 查看结果        System.out.println(resultList.size());        System.out.println(resultList.stream().sorted().collect(Collectors.toList()));    }}class MultiThread extends Thread {    private List<Integer> idList;    private CountDownLatch countDownLatch;    private List<Integer> result;    public void setResultList(List<Integer> result) {        this.result = result;    }    public void setIdList(List<Integer> idList) {        this.idList = idList;    }    public void setCountDownLatch(CountDownLatch countDownLatch) {        this.countDownLatch = countDownLatch;    }    @Override    public void run() {        try {            // 数据处理            for (Integer integer : idList) {                if (integer % 2 == 0) {                    result.add(integer);                }            }        } catch (Exception e) {            e.printStackTrace();        } finally {            if (countDownLatch != null) {                countDownLatch.countDown();            }        }    }