四線程讀寫_牛客網

題目

設計 4 個線程，其中兩個線程每次對 j 增加 1 ，另外兩個線程對 j 每次減少 1. 寫出程序。

Java實現（轉自牛客@冰封無痕）

package src;

/**
 * Created by Administrator on 2017/8/22.
 */

class Resoure
    private int j = 0;
    public synchronized void add() {
        j++;
        System.out.println(Thread.currentThread().getName() + "...add..." +
                "當前j值" + j);
    }

    public synchronized void des() {
        j--;
        System.out.println(Thread.currentThread().getName() + "...des..." +
                "當前j值" + j);
    }
}

public class FourThreadTest {
    //new object
    private Resoure res = new Resoure();

    public static void main(String[] args) {
        FourThreadTest fourThread = new FourThreadTest();
        fourThread.test();
    }

    private void test() {
        for (int i = 0; i < 2; i++) {
            new Thread(new Runnable() {
                @Override
                public void run() {
                    while (true) {
                        try {
                            Thread.sleep((long) (Math.random() * 1000));
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                        res.add();
                    }
                }
            }).start();

            new Thread(new Runnable() {
                @Override
                public void run() {
                    while (true) {
                        try {
                            Thread.sleep((long) (Math.random() * 1000));
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                        res.des();
                    }
                }
            }).start();
        }
    }
}