多个线程顺序执行

1.wait-notifyAll

同步方法

package com.study.demo;

/**
 * Created by Administrator on 2019\3\2 0002.
 */
public class Test {
    private int seq = 1;

    public synchronized void method1() {
        try {
            while (seq != 1) {
                wait();
            }
            System.out.println(Thread.currentThread().getName() + " method1 run");
            seq = 2;
            notifyAll();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    public synchronized void method2() {
        try {
            while (seq != 2) {
                wait();
            }
            System.out.println(Thread.currentThread().getName() + " method2 run");
            seq = 3;
            notifyAll();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    public synchronized void method3() {
        try {
            while (seq != 3) {
                wait();
            }
            System.out.println(Thread.currentThread().getName() + " method3 run");
            seq = 4;
            notifyAll();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        Test test = new Test();
        new Thread1(test).start();
        new Thread2(test).start();
        new Thread3(test).start();
    }

}

class Thread1 extends Thread {
    private Test test;

    public Thread1(Test test) {
        this.test = test;
    }

    @Override
    public void run() {
        test.method1();
    }
}

class Thread2 extends Thread {
    private Test test;

    public Thread2(Test test) {
        this.test = test;
    }

    @Override
    public void run() {
        test.method2();
    }
}

class Thread3 extends Thread {
    private Test test;

    public Thread3(Test test) {
        this.test = test;
    }

    @Override
    public void run() {
        test.method3();
    }
}

method1 run
method2 run
method3 run

同步代码块

package com.study.demo;

/**
 * Created by Administrator on 2019\3\2 0002.
 */
public class Test {
    private int seq = 1;
    private final Object lock = new Object();

    public void method1() {
        synchronized (lock) {
            try {
                while (seq != 1) {
                    lock.wait();
                }
                System.out.println(Thread.currentThread().getName() + " method1 run");
                seq = 2;
                lock.notifyAll();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    public void method2() {
        synchronized (lock) {
            try {
                while (seq != 2) {
                    lock.wait();
                }
                System.out.println(Thread.currentThread().getName() + " method2 run");
                seq = 3;
                lock.notifyAll();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    public void method3() {
        synchronized (lock) {
            try {
                while (seq != 3) {
                    lock.wait();
                }
                System.out.println(Thread.currentThread().getName() + " method3 run");
                seq = 4;
                lock.notifyAll();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    public static void main(String[] args) {
        Test test = new Test();
        new Thread1(test).start();
        new Thread2(test).start();
        new Thread3(test).start();
    }

}

class Thread1 extends Thread {
    private Test test;

    public Thread1(Test test) {
        this.test = test;
    }

    @Override
    public void run() {
        test.method1();
    }
}

class Thread2 extends Thread {
    private Test test;

    public Thread2(Test test) {
        this.test = test;
    }

    @Override
    public void run() {
        test.method2();
    }
}

class Thread3 extends Thread {
    private Test test;

    public Thread3(Test test) {
        this.test = test;
    }

    @Override
    public void run() {
        test.method3();
    }
}

2.await-signal

package com.study.demo;

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

/**
 * Created by Administrator on 2019\3\2 0002.
 */
public class Test {
    private int seq = 1;
    private final ReentrantLock lock = new ReentrantLock();
    private final Condition condition1 = lock.newCondition();
    private final Condition condition2 = lock.newCondition();
    private final Condition condition3 = lock.newCondition();

    public void method1() {
        lock.lock();
        try {
            while (seq != 1) {
                condition1.await();
            }
            System.out.println(Thread.currentThread().getName() + " method1 run");
            seq = 2;
            condition2.signal();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }
    }

    public void method2() {
        lock.lock();
        try {
            while (seq != 2) {
                condition1.await();
            }
            System.out.println(Thread.currentThread().getName() + " method2 run");
            seq = 3;
            condition3.signal();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }
    }

    public void method3() {
        lock.lock();
        try {
            while (seq != 3) {
                condition3.await();
            }
            System.out.println(Thread.currentThread().getName() + " method3 run");
            seq = 4;
            condition1.signal();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }
    }

    public static void main(String[] args) {
        Test test = new Test();
        new Thread1(test).start();
        new Thread2(test).start();
        new Thread3(test).start();
    }

}

class Thread1 extends Thread {
    private Test test;

    public Thread1(Test test) {
        this.test = test;
    }

    @Override
    public void run() {
        test.method1();
    }
}

class Thread2 extends Thread {
    private Test test;

    public Thread2(Test test) {
        this.test = test;
    }

    @Override
    public void run() {
        test.method2();
    }
}

class Thread3 extends Thread {
    private Test test;

    public Thread3(Test test) {
        this.test = test;
    }

    @Override
    public void run() {
        test.method3();
    }
}

3.join方法

package com.study.demo;

/**
 * Created by Administrator on 2019\3\2 0002.
 */
public class Test {

    public static void main(String[] args) throws InterruptedException {
        Thread1 thread1 = new Thread1();
        thread1.start();
        thread1.join();

        Thread1 thread2 = new Thread1();
        thread2.start();
        thread2.join();

        Thread1 thread3 = new Thread1();
        thread3.start();
        thread3.join();

    }

}

class Thread1 extends Thread {
    @Override
    public void run() {
        System.out.println(Thread.currentThread().getName() + " run");
    }
}

Thread-0 run
Thread-1 run
Thread-2 run

4.Semaphore信号量

package com.study.demo;

import java.util.concurrent.Semaphore;

/**
 * Created by Administrator on 2019\3\2 0002.
 */
public class Test {

    private static Semaphore A = new Semaphore(1);
    private static Semaphore B = new Semaphore(1);
    private static Semaphore C = new Semaphore(1);

    public static void main(String[] args) {
        ThreadA a = new ThreadA();
        ThreadB b = new ThreadB();
        ThreadC c = new ThreadC();

        try {
            B.acquire();
            C.acquire();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        a.start();
        b.start();
        c.start();
    }

    static class ThreadA extends Thread {
        @Override
        public void run() {
            try {
                A.acquire();
                System.out.println("thread a run");
                B.release();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    static class ThreadB extends Thread {
        @Override
        public void run() {
            try {
                B.acquire();
                System.out.println("thread b run");
                C.release();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    static class ThreadC extends Thread {
        @Override
        public void run() {
            try {
                C.acquire();
                System.out.println("thread c run");
                A.release();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}