Java多种方式实现生产者消费者模式

实现需求：两个线程交替打印1,0，打印10轮

java多线程口诀：

• 高内聚，低耦合

• 线程操作资源类

• 判断干活通知

• 防止虚假唤醒
  

方式一：使用synchronized和Object的wait和notifyAll方法

wait:使当前线程阻塞

notify,notifyAll唤醒当前线程

/**
* 两个线程交替打印1，0 打印10轮
*
* @author Administrator
* @version 1.0 2020年7月12日
* @see ProdConsumerDemo1
* @since 1.0
*
*/
class ShareData1 {

public int number = 0;

public synchronized void increment() throws Exception {
   while (number != 0) {
     this.wait();
   }
   number++;
   System.out.println(Thread.currentThread().getName() + " " + number);
   this.notifyAll();
 }

public synchronized void decrement() throws InterruptedException {
   while (number != 1) {
     this.wait();
   }
   number--;
   System.out.println(Thread.currentThread().getName() + " " + number);
   this.notifyAll();
 }
}

public class ProdConsumerDemo1 {

public static void main(String[] args) {
   ShareData1 shareData = new ShareData1();
   new Thread(() -> {
     for (int i = 0; i < 10; i++) {
       try {
         shareData.increment();
       } catch (Exception e) {
         // TODO Auto-generated catch block
         e.printStackTrace();
       }
     }
   }, "A").start();
   new Thread(() -> {
     for (int i = 0; i < 10; i++) {
       try {
         shareData.decrement();
       } catch (Exception e) {
         // TODO Auto-generated catch block
         e.printStackTrace();
       }
     }
   }, "B").start();
 }
}

输出结果

A 1
B 0
A 1
B 0
A 1
B 0
A 1
B 0
A 1
B 0
A 1
B 0
A 1
B 0
A 1
B 0
A 1
B 0
A 1
B 0

方式二：使用jdk1.8的Lock和Condition

class ShareData2 {

private int number = 0;

private Lock lock = new ReentrantLock();

private Condition condition = lock.newCondition();

public void increment() throws Exception {
   lock.lock();
   try {
     while (number != 0) {
       condition.await();
     }
     number++;
     System.out.println(Thread.currentThread().getName() + " " + number);
     condition.signalAll();
   } finally {
     lock.unlock();
   }
 }

public void decrement() throws InterruptedException {
   lock.lock();
   try {
     while (number != 1) {
       condition.await();
     }
     number--;
     System.out.println(Thread.currentThread().getName() + " " + number);
     condition.signalAll();
   } finally {
     // TODO: handle finally clause
     lock.unlock();
   }
 }
}

public class ProdConsumerDemo2 {

public static void main(String[] args) {
   ShareData2 shareData = new ShareData2();
   new Thread(() -> {
     for (int i = 0; i < 10; i++) {
       try {
         shareData.increment();
       } catch (Exception e) {
         // TODO Auto-generated catch block
         e.printStackTrace();
       }
     }
   }, "A").start();
   new Thread(() -> {
     for (int i = 0; i < 10; i++) {
       try {
         shareData.decrement();
       } catch (Exception e) {
         // TODO Auto-generated catch block
         e.printStackTrace();
       }
     }
   }, "B").start();
 }
}

输出结果

A 1
B 0
A 1
B 0
A 1
B 0
A 1
B 0
A 1
B 0
A 1
B 0
A 1
B 0
A 1
B 0
A 1
B 0
A 1
B 0

主要是熟悉Lock和Condition的使用

Lock和Condition相比于synchronized，能够精确唤醒

需求：三个线程A,B,C顺序打印，A打印5次，B打印10次，C打印15次，10轮

class ShareData3 {

private int number = 1;

private Lock lock = new ReentrantLock();

private Condition c1 = lock.newCondition();

private Condition c2 = lock.newCondition();

private Condition c3 = lock.newCondition();

public void print5() throws Exception {
   lock.lock();
   try {
     while (number != 1) {
       c1.await();
     }
     number = 2;
     for (int i = 0; i < 5; i++) {
       System.out.println(Thread.currentThread().getName() + " " + i);
     }
     c2.signalAll();
   } finally {
     // TODO: handle finally clause
     lock.unlock();
   }
 }

public void print10() throws InterruptedException {
   lock.lock();
   try {
     while (number != 2) {
       c2.await();
     }
     number=3;
     for (int i = 0; i < 10; i++) {
       System.out.println(Thread.currentThread().getName() + " " + i);
     }
     c3.signalAll();
   } finally {
     // TODO: handle finally clause
     lock.unlock();
   }
 }

public void print15() throws InterruptedException {
   lock.lock();
   try {
     while (number != 3) {
       c3.await();
     }
     number = 1;
     for (int i = 0; i < 15; i++) {
       System.out.println(Thread.currentThread().getName() + " " + i);
     }
     c1.signalAll();
   } finally {
     // TODO: handle finally clause
     lock.unlock();
   }
 }
}

public class ProdConsumerDemo3 {

public static void main(String[] args) {
   ShareData3 shareData3 = new ShareData3();
   new Thread(() -> {
     try {
       for (int i = 0; i < 10; i++) {
         shareData3.print5();
       }
     } catch (Exception e) {
       // TODO Auto-generated catch block
       e.printStackTrace();
     }
   }, "A").start();
   new Thread(() -> {
     try {
       for (int i = 0; i < 10; i++) {
         shareData3.print10();
       }
     } catch (Exception e) {
       // TODO Auto-generated catch block
       e.printStackTrace();
     }
   }, "B").start();
   new Thread(() -> {
     try {
       for (int i = 0; i < 10; i++) {
         shareData3.print15();
       }
     } catch (Exception e) {
       // TODO Auto-generated catch block
       e.printStackTrace();
     }
   }, "C").start();
 }
}

来源：https://www.cnblogs.com/lt123/p/13290098.html