Exercise

创建三个线程：一个线程打印 100个A,一个线程打印 100 个 B ，一个线程打印 100个C 输出效果：ABC ABC ABC…交替打印

package com.kane.exercise01;  public class PrintABC implements Runnable {      private static final Object lock = new Object();     private static int state = 0;      private String str;     private int num;      public PrintABC(String str, int num) {         this.str = str;         this.num = num;     }      @Override     public void run() {         for (int i = 0; i < 100; i++) {             synchronized (lock) {                 while (state % 3 != num) {                     try {                         lock.wait();                     } catch (InterruptedException e) {                         e.printStackTrace();                     }                 }                 System.out.print(str);                 state++;                 lock.notifyAll(); // 唤醒其他线程             }             if(state%3 == 0) {                 System.out.println("");             }         }     } }   

package com.kane.exercise01;  public class Demo1 {     public static void main(String[] args) {         Thread t1 = new Thread(new PrintABC("A",0));         Thread t2 = new Thread(new PrintABC("B",1));         Thread t3 = new Thread(new PrintABC("C",2));         t1.start();         t2.start();         t3.start();     } }  

编写两个线程，一个 线程打印1-52，另一个线程打印字母A-Z打印顺序是12A34B…,即按照整数和字母的顺序从小到大打印，并且每打印两个整数后，打印一个字母，交替循环打印

package com.kane.exercise02;  import java.util.concurrent.Semaphore;  public class Demo {     private static final Semaphore Numbersemaphore = new Semaphore(1);     private static final Semaphore Dansemaphore = new Semaphore(0);      public static void main(String[] args) {         Thread t1 = new Thread(new NumberPrint());         Thread t2 = new Thread(new DanPrint());         t1.start();         t2.start();     }      static class NumberPrint implements Runnable {          @Override         public void run() {             for (int i = 1; i < 53; i++) {                 try {                     Numbersemaphore.acquire();                     System.out.print(i + " ");                     if (i%2== 0) {                         Dansemaphore.release();                     } else {                         Numbersemaphore.release();                     }                 } catch (InterruptedException e) {                     throw new RuntimeException(e);                 }             }         }     }     static class DanPrint implements Runnable {          @Override         public void run() {             for (char c = 'A'; c <= 'Z'; c++) {                 try {                     Dansemaphore.acquire();                     System.out.print(c);                     System.out.println("");                     Numbersemaphore.release();                 } catch (InterruptedException e) {                     Thread.currentThread().interrupt();                 }             }         }     }  }