Java多种方式实现生产者消费者模式

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-genehttp://rated 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-generatedQzwWDXR 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();

}

}

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