算法题---五个线程排序输出

1、五个线程编号1、2、3、4、5，每个线程的执行完成时间不确定，要求按照排号顺序输出各个线程的结果，并且不能等所有线程执行完毕再排序输出，比如线程2先于线程1执行完了此时还不能输出。要等线程1输出完之后才能输出，其他线程以此类推

方案一、利用所得传递，创建五把锁 lock 1、2、3、4、5，线程1创建的时候lock1.lock 执行完毕后lock1.unlock 当线程2创建时候lock2.lock，输出方法里调用lock1.lock，输出完成之后执行lock1.unlock，再执行lock2.unlock，目的就是线程1把lock1释放之后 线程2才能获取到lock1然后才可以输出，后边的线程以此类推：

 public void test() {
        ReentrantLock lock1 = new ReentrantLock();
        ReentrantLock lock2 = new ReentrantLock();
        ReentrantLock lock3 = new ReentrantLock();
        ReentrantLock lock4 = new ReentrantLock();
        ReentrantLock lock5 = new ReentrantLock();

        Thread1 thread1 = new Thread1(lock1);
        Thread1 thread2 = new Thread2(lock1, lock2);
        Thread1 thread3 = new Thread3(lock2, lock3);
        Thread1 thread4 = new Thread4(lock3, lock4);
        Thread1 thread5 = new Thread5(lock4, lock5);
    }

class Thread1 extends Thread {
        ReentrantLock lock1;

        Thread1(ReentrantLock lock1) {
            this.lock1 = lock1;
            this.lock1.lock();
        }

        void doSomeThing() {

        }

        private void doPrint() {
            System.out.println("result1");
            lock1.unlock();
        }

        @Override
        public void run() {
            super.run();

            doSomeThing();
            doPrint();
        }
    }

class Thread2 extends Thread {
        ReentrantLock lock1;
        ReentrantLock lock2;

        Thread2(ReentrantLock lock1, ReentrantLock lock2) {
            this.lock1 = lock1;
            this.lock2 = lock2;
            this.lock2.lock();
        }

        void doSomeThing() {

        }

        private void doPrint() {
            lock1.lock();
            System.out.println("result1");
            lock1.unlock();
            lock2.unlock();
        }

        @Override
        public void run() {
            super.run();

            doSomeThing();
            doPrint();
        }
    }

方案二、利用线程的join方法，在本线程输出时使用前一个线程的join方法等待前一个执行完毕

 public void testX() {
        ThreadX thread1 = new ThreadX(null);
        ThreadX thread2 = new ThreadX(thread1);
        ThreadX thread3 = new ThreadX(thread2);
        ThreadX thread4 = new ThreadX(thread3);
        ThreadX thread5 = new ThreadX(thread4);
    }

class ThreadX extends Thread {
        Thread threadPre;

        ThreadX(Thread threadPre) {
            this.threadPre = threadPre;
        }

        void doSomeThing() {

        }

        private void doPrint() {
            try {
                if (threadPre != null) {
                    threadPre.join();
                }
                System.out.println("result1");
            } catch (InterruptedException e) {
                e.printStackTrace();
            }

        }

        @Override
        public void run() {
            super.run();

            doSomeThing();
            doPrint();
        }
    }