ThreadLocal相关代码和面试题

1代码1

class House {
    int saleCount = 0;

    public synchronized void saleHouse() {
        saleCount++;
    }

//    ThreadLocal<Integer> saleVolume = new ThreadLocal<Integer>() {
//        @Override
//        protected Integer initialValue() {
//            return 0;
//        }
//    }; 

    ThreadLocal<Integer> saleVolume = ThreadLocal.withInitial(() -> 0);

    public void saleVolumeByThreadLocal() {
        saleVolume.set(1 + saleVolume.get());
    }
}

public class ThreadLocalDemo {

    public static void main(String[] args) {

        House house = new House();

        for (int i = 1; i <= 5; i++) {
            try {
                new Thread(() -> {
                    int size = new Random().nextInt(5) + 1;
                    // System.out.println(size);
                    for (int j = 1; j <= size; j++) {
                        house.saleHouse();
                        house.saleVolumeByThreadLocal();
                    }
                    System.out.println(Thread.currentThread().getName() + "\t" + "卖出多少套" + house.saleVolume.get());

                }, String.valueOf(i)).start();
            }catch (Exception e) {

            }finally {
                house.saleVolume.remove();
            }
        }

        try {
            TimeUnit.MILLISECONDS.sleep(300);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        System.out.println(Thread.currentThread().getName() + "\t" + "共卖出多少套:" + house.saleCount);

    }
}

2.代码2

class MyData {

    ThreadLocal<Integer> threadLocalField = ThreadLocal.withInitial(() -> 0);

    public void add() {
        threadLocalField.set(1 + threadLocalField.get());
    }
}

public class ThreadLocalDemo1 {

    public static void main(String[] args) {
        ExecutorService threadPool = Executors.newFixedThreadPool(3);
        MyData myData = new MyData();

        try {
            for (int i = 0; i < 10; i++) {
                threadPool.submit(() -> {
                    try {
                        Integer beforeInt = myData.threadLocalField.get();
                        myData.add();
                        Integer afterInt = myData.threadLocalField.get();
                        System.out.println(Thread.currentThread().getName() + "\t" + "beforeInt " + beforeInt + "\t" + " afterInt " + afterInt);
                    } finally {
                        myData.threadLocalField.remove();
                    }
                });
            }
        } finally {
            threadPool.shutdown();
        }

        try {
            TimeUnit.MILLISECONDS.sleep(300);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

    }
}

标签：面试题,int,代码,myData,ThreadLocal,void,threadLocalField,public
来源： https://www.cnblogs.com/liuyi13535496566/p/16389739.html