JAVA多線程按指定順序執行線程 Condition應用

package concurrent;

import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;

/**
 * Auth: zhouhongliang
 * Date：2019/8/1
 * 線程等待與喚醒機制 Condition
 * 按指定順序執行線程
 */
public class ConditionDemo {
    public static void main(String[] args) {
        //聲明重入鎖
        ReentrantLock reentrantLock = new ReentrantLock();
        //聲明Condition對象
        final Condition condition1 = reentrantLock.newCondition();
        final Condition condition2 = reentrantLock.newCondition();
        final Condition condition3 = reentrantLock.newCondition();
        new Thread(() -> {
            //加鎖
            reentrantLock.lock();
            try {
                //等待
                condition1.await();
                System.out.println("AA");
            } catch (InterruptedException e) {
                e.printStackTrace();
            } finally {
                //解鎖
                reentrantLock.unlock();
            }
        }).start();
        new Thread(() -> {
            reentrantLock.lock();
            try {
                condition2.await();
                System.out.println("BB");
                condition1.signal();
            } catch (InterruptedException e) {
                e.printStackTrace();
            } finally {
                reentrantLock.unlock();
            }
        }).start();
        new Thread(() -> {
            reentrantLock.lock();
            try {
                condition3.await();
                System.out.println("CC");
                condition2.signal();
            } catch (InterruptedException e) {
                e.printStackTrace();
            } finally {
                reentrantLock.unlock();
            }
        }).start();
        new Thread(() -> {
            reentrantLock.lock();
            try {
                System.out.println("DD");
                //喚醒
                condition3.signal();
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                reentrantLock.unlock();
            }
        }).start();
    }
}

輸出結果：
DD
CC
BB
AA

Process finished with exit code 0