public class SynchronizedTest {

 //定義個year，用來記錄某明星的練習(xí)年數(shù)
 private static double year;

 public void run() {
  //線程A，練習(xí)唱跳rap
  Thread threadA = new Thread(() -> {
   synchronized (this) {
    for (year = 0.5; year <= 5; year += 0.5) {
     System.out.println("蔡徐雞開始練習(xí)唱跳rap：已練習(xí)" + year + "年");
     try {
      Thread.sleep(288);
     } catch (InterruptedException e) {
      e.printStackTrace();
     }
     //眾所周知，練習(xí)兩年半即可出道
     if (year == 2.5) {
      System.out.println("===========================>成功練習(xí)兩年半，出道?。?！");
      this.notify();
     }
    }
   }
  });
  //線程B，練習(xí)打籃球
  Thread threadB = new Thread(() -> {
   while (true) {
    synchronized (this) {
     try {
      this.wait();
     } catch (InterruptedException e) {
      e.printStackTrace();
     }
     System.out.println("蔡徐雞開始練習(xí)打籃球");
    }
   }
  });
  //注意，一定要先啟動B，不然會導(dǎo)致B永遠(yuǎn)拿不到鎖
  threadB.start();
  threadA.start();
 }

 public static void main(String[] args) {
  SynchronizedTest test = new SynchronizedTest();
  test.run();
 }
}

public class LockTest {
  //定義個year，用來記錄某明星練習(xí)打籃球的年數(shù)
  private static double year;

  public static void main(String[] args) {
   ReentrantLock lock = new ReentrantLock();
   Condition condition = lock.newCondition();
   //線程A，練習(xí)唱跳rap
   Thread threadA = new Thread(() -> {
    //執(zhí)行業(yè)務(wù)代碼前上鎖
    lock.lock();
    for (year = 0.5; year <= 5; year += 0.5) {
     System.out.println("蔡徐雞開始練習(xí)唱跳rap：已練習(xí)" + year + "年");
     try {
      Thread.sleep(288);
     } catch (InterruptedException e) {
      e.printStackTrace();
     }
     //眾所周知，練習(xí)兩年半即可出道
     if (year == 2.5) {
      System.out.println("===========================>成功練習(xí)兩年半，出道?。?！");
      //喚醒等待中的線程
      condition.signal();
     }
    }
    //業(yè)務(wù)代碼執(zhí)行完后解鎖
    lock.unlock();
   });
   //線程B，練習(xí)打籃球
   Thread threadB = new Thread(() -> {
    //執(zhí)行業(yè)務(wù)代碼前上鎖
    lock.lock();
    while (true) {
     try {
      //讓線程等待，如果計數(shù)器為0的話，則立即執(zhí)行
      condition.await();
     } catch (InterruptedException e) {
      e.printStackTrace();
     }
     System.out.println("蔡徐老母雞開始練習(xí)打籃球");
     break;
    }
    //業(yè)務(wù)代碼執(zhí)行完后解鎖
    lock.unlock();
   });
   //注意，一定要先啟動B，不然會導(dǎo)致B永遠(yuǎn)拿不到鎖
   threadB.start();
   threadA.start();
  }
 }

public class volatileTest {
 //定義一個共享變量，注意，必須用volatile修飾
 static volatile boolean flag = false;
 //定義個year，用來記錄某明星練習(xí)打籃球的年數(shù)
 private static double year;

 public static void main(String[] args) {
  //線程A，練習(xí)唱跳rap
  Thread threadA = new Thread(() -> {
   while (true) {
    if (!flag) {
     for (year = 0.5; year <= 5; year += 0.5) {
      System.out.println("蔡徐雞開始練習(xí)唱跳rap：已練習(xí)" + year + "年");
      try {
       Thread.sleep(288);
      } catch (InterruptedException e) {
       e.printStackTrace();
      }
      //眾所周知，練習(xí)兩年半即可出道
      if (year == 2.5) {
       System.out.println("===========================>成功練習(xí)兩年半，出道！?。?);
       year = 0.5;
       flag = true;
       break;
      }
     }
    }
   }
  });
  //線程B，練習(xí)打籃球
  Thread threadB = new Thread(() -> {
   while (true) {
    if (flag) {
     System.out.println("蔡徐老母雞開始練習(xí)打籃球");
     break;
    }
   }
  });
  //　啟動線程
  threadA.start();
  threadB.start();
 }
}

public class CountDownLatchTest {
 //定義個year，用來記錄某明星練習(xí)打籃球的年數(shù)
 private static double year;

 public static void main(String[] args) {
  CountDownLatch latch = new CountDownLatch(1);
  //線程A，練習(xí)唱跳rap
  Thread threadA = new Thread(() -> {
   for (year = 0.5; year <= 5; year += 0.5) {
    System.out.println("蔡徐雞開始練習(xí)唱跳rap：已練習(xí)" + year + "年");
    try {
     Thread.sleep(288);
    } catch (InterruptedException e) {
     e.printStackTrace();
    }
    //眾所周知，練習(xí)兩年半即可出道
    if (year == 2.5) {
     System.out.println("===========================>成功練習(xí)兩年半，出道?。。?);
     //計數(shù)器減一
     latch.countDown();
    }
   }
  });
  //線程B，練習(xí)打籃球
  Thread threadB = new Thread(() -> {
   while (true) {
    try {
     //讓線程等待，如果計數(shù)器為0的話，則立即執(zhí)行
     latch.await();
    } catch (InterruptedException e) {
     e.printStackTrace();
    }
    System.out.println("蔡徐老母雞開始練習(xí)打籃球");
    break;
   }
  });
  //　啟動線程
  threadA.start();
  threadB.start();
 }
}