两道多线程打印题目 java

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 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 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; }} }

【两道多线程打印题目】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(); }}