Java 指定线程执行顺序（三种方式）

/**
 * 指定线程执行顺序：通过synchronized共享对象锁加上volatile可见变量来实现
 */
public class ThreadOrder {

    private volatile int orderNum = 1;

    public synchronized void methodA() {
        try {
            while (orderNum != 1) {
                wait();
            }
            for (int i = 0; i < 2; i++) {
                System.out.println("AAAAA");
            }
            orderNum = 2;
            notifyAll();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    public synchronized void methodB() {
        try {
            while (orderNum != 2) {
                wait();
            }
            for (int i = 0; i < 2; i++) {
                System.out.println("BBBBB");
            }
            orderNum = 3;
            notifyAll();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    public synchronized void methodC() {
        try {
            while (orderNum != 3) {
                wait();
            }
            for (int i = 0; i < 2; i++) {
                System.out.println("CCCCC");
            }
            orderNum = 1;
            notifyAll();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

package com.example.concurrent;

import org.junit.Test;

public class ThreadOrderTest {

	/**
	 * 指定线程执行顺序：通过共享对象锁加上可见变量来实现
	 * 
	 * @throws Exception
	 */
	@Test
	public void test() throws Exception {
		ThreadOrder threadOrder = new ThreadOrder();

		Thread thread1 = new Thread(new Runnable() {

			@Override
			public void run() {
				// TODO Auto-generated method stub
				threadOrder.methodA();
			}
		});

		Thread thread2 = new Thread(new Runnable() {

			@Override
			public void run() {
				// TODO Auto-generated method stub
				threadOrder.methodB();
			}
		});

		Thread thread3 = new Thread(new Runnable() {

			@Override
			public void run() {
				// TODO Auto-generated method stub
				threadOrder.methodC();
			}
		});

		thread1.start();
		thread2.start();
		thread3.start();
	}
}

AAA
AAA
BBB
BBB
CCC
CCC

package com.example.concurrent;

import org.junit.Test;

public class ThreadOrderTest {

	/**
	 * 通过主线程join()
	 * 
	 * @throws Exception
	 */
	@Test
	public void test2() throws Exception {
		Thread thread1 = new Thread(new Runnable() {

			@Override
			public void run() {
				// TODO Auto-generated method stub
				System.out.println("AAA");
			}
		});

		Thread thread2 = new Thread(new Runnable() {

			@Override
			public void run() {
				// TODO Auto-generated method stub
				System.out.println("BBB");
			}
		});

		Thread thread3 = new Thread(new Runnable() {

			@Override
			public void run() {
				// TODO Auto-generated method stub
				System.out.println("CCC");
			}
		});

		thread1.start();
		thread1.join();
		thread2.start();
		thread2.join();
		thread3.start();
		thread3.join();
	}
}

AAA
BBB
CCC

class T1 extends Thread {
    public void run(){
        Random random = new Random();
        try {
            Thread.sleep(random.nextInt(1000));
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println("in T1");
    }
}

class T2 extends Thread{
    private Thread thread;
    public T2(Thread thread) {
        this.thread = thread;
    }

    public void run(){
        try {
            thread.join();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println("in T2");
    }
}

class T3 extends Thread{
    private Thread thread;
    public T3(Thread thread) {
        this.thread = thread;
    }

    public void run(){
        try {
            thread.join();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println("in T3");
    }
}

public class Test {
    public static void main(String[] args) throws InterruptedException {
        T1 t1 = new T1();
        T2 t2 = new T2(t1);
        T3 t3 = new T3(t2);
        t2.start();
        t1.start();
        t3.start();
    }
}

in T1
in T2
in T3