两道多线程打印题目

来源：互联网发布：内涵吧源码编辑：程序博客网时间：2024/06/07 22:41

1.每个线程打印不同的字符

public class ThreadPrint{    public static void main(String[] args)        throws InterruptedException    {        String str = "ABCD";        int index = 4;        Character c;        Map<Character, MyLock> locks = new HashMap<>();        MyLock lock = new MyLock();        for (int i = 0; i < index; i++)        {            for (int j = 0; j < str.length(); j++)            {                c = str.charAt(j);                if (null == locks.get(c))                {                    lock = new MyLock();                    lock.setCountDownLatch(new CountDownLatch(1));                    new Thread(new MyRunnable(c, lock)).start();                    locks.put(c, lock);                    lock.getCountDownLatch().await();                }                else                {                    lock = locks.get(c);                    lock.setCountDownLatch(new CountDownLatch(1));                    synchronized (lock)                    {                        locks.get(c).notify();                    }                    lock.getCountDownLatch().await();                }            }        }        for (Entry<Character, MyLock> entry : locks.entrySet())        {            synchronized (entry.getValue())            {                entry.getValue().setEnd(true);                entry.getValue().notify();            }        }    }    static class MyLock    {        private boolean end = false;        private CountDownLatch countDownLatch;        public CountDownLatch getCountDownLatch()        {            return countDownLatch;        }        public void setCountDownLatch(CountDownLatch countDownLatch)        {            this.countDownLatch = countDownLatch;        }        public boolean isEnd()        {            return end;        }        public void setEnd(boolean end)        {            this.end = end;        }    }    static class MyRunnable implements Runnable    {        private char c;        private MyLock lock;        public MyRunnable(char c, MyLock lock)        {            this.c = c;            this.lock = lock;        }        @Override        public void run()        {            synchronized (lock)            {                while (!lock.isEnd())                {                    System.out.print(c);                    lock.getCountDownLatch().countDown();                    try                    {                        lock.wait();                    }                    catch (InterruptedException e)                    {                        e.printStackTrace();                    }                }            }        }        public char getC()        {            return c;        }        public void setC(char c)        {            this.c = c;        }    }}

2.两个线程交替打印一段字符串

public class PrintWithTwoThread{    static int i = 0;    public static void main(String[] args)    {        String str = "I'am hahaha";        new Thread(() -> {            synchronized (str)            {                while (i < str.length())                {                    System.out.println(Thread.currentThread().getName() + ":" + str.charAt(i));                    i++;                    try                    {                        str.notify();                        str.wait();                    }                    catch (InterruptedException e)                    {                        e.printStackTrace();                    }                }                str.notify();            }        }, "1").start();        new Thread(() -> {            synchronized (str)            {                while (i < str.length())                {                    System.out.println(Thread.currentThread().getName() + ":" + str.charAt(i));                    i++;                    try                    {                        str.notify();                        str.wait();                    }                    catch (InterruptedException e)                    {                        e.printStackTrace();                    }                }                str.notify();            }        }, "2").start();    }}

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