[移动开发]Java深入解析_并发编程专题（Java锁机制、Disruptor）

一、Java锁机制

1.自旋转锁与互斥锁区别

互斥锁：线程会从sleep（加锁）?running（解锁），过程中有上下文的切换，CPU的抢占，信号的发送等开销。
自旋锁：线程一直是running（加锁?解锁），死循环检测锁的标志位，机制不复杂。

2.公平与非公平锁

二、Disruptor

1.disruptor原理

2.创建disruptor消费端与生产者

Pom Maven依赖信息

	<dependencies>
		<dependency>
			<groupId>com.lmax</groupId>
			<artifactId>disruptor</artifactId>
			<version>3.2.1</version>
		</dependency>
	</dependencies>

package com.itmayiedu.entity;

//声明一个event 生产者与消费者传递数据类型
public class LongEvent {

	private Long value;

	public Long getValue() {
		return value;
	}

	public void setValue(Long value) {
		this.value = value;
	}

}

package com.itmayiedu.factory;

import com.itmayiedu.entity.LongEvent;
import com.lmax.disruptor.EventFactory;

// EventFactory 实例化LongEvent
public class LongEventFactory implements EventFactory<LongEvent> {

	public LongEvent newInstance() {

		return new LongEvent();
	}

}

package com.itmayiedu.consumer;

import com.itmayiedu.entity.LongEvent;
import com.lmax.disruptor.EventHandler;

//消费者获取生产推送数据
public class LongEventHandler implements EventHandler<LongEvent> {

	public void onEvent(LongEvent event, long sequence, boolean endOfBatch) throws Exception {
		System.out.println("消费者1 获取生产者数据..event:" + event.getValue());
	}

}

package com.itmayiedu.consumer;

import com.itmayiedu.entity.LongEvent;
import com.lmax.disruptor.EventHandler;

//消费者获取生产推送数据
public class LongEventHandler2 implements EventHandler<LongEvent> {

	public void onEvent(LongEvent event, long sequence, boolean endOfBatch) throws Exception {
		System.out.println("消费者2 获取生产者数据..event:" + event.getValue());
	}

}

package com.itmayiedu.producer;

import java.nio.ByteBuffer;

import com.itmayiedu.entity.LongEvent;
import com.lmax.disruptor.RingBuffer;

// 生产者
public class LongEventProducer {
	private RingBuffer<LongEvent> ringBuffer;

	public LongEventProducer(RingBuffer<LongEvent> ringBuffer) {
		this.ringBuffer = ringBuffer;
	}

	public void onData(ByteBuffer byteBuffer) {
		// 获取事件队列 下标位置
		long sequence = ringBuffer.next();
		try {
			// 取出空队列（Event）
			LongEvent longEvent = ringBuffer.get(sequence);
			// 给空队列赋值
			longEvent.setValue(byteBuffer.getLong(0));
		} catch (Exception e) {
			// TODO: handle exception
		} finally {
			System.out.println("生产者发送数据...");
			// 发送数据
			ringBuffer.publish(sequence);
		}
	}

}

package com.itmayiedu.producer;

import java.nio.ByteBuffer;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import com.itmayiedu.consumer.LongEventHandler;
import com.itmayiedu.consumer.LongEventHandler2;
import com.itmayiedu.entity.LongEvent;
import com.itmayiedu.factory.LongEventFactory;
import com.lmax.disruptor.EventFactory;
import com.lmax.disruptor.RingBuffer;
import com.lmax.disruptor.YieldingWaitStrategy;
import com.lmax.disruptor.dsl.Disruptor;
import com.lmax.disruptor.dsl.ProducerType;

public class Main {

	public static void main(String[] args) {
		// 1.创建可以缓存的线程池，提供发给consumer
		ExecutorService executor = Executors.newCachedThreadPool();
		// 2.创建 Event工厂
		EventFactory<LongEvent> eventFactory = new LongEventFactory();
		// 3.创建ringbuffer大小
		int ringbuffer = 1024 * 1024;// 2的N次方。
		// 4.创建Disruptor
		Disruptor<LongEvent> disruptor = new Disruptor<LongEvent>(eventFactory, ringbuffer, executor,
				ProducerType.MULTI, new YieldingWaitStrategy());
		// 5.连接消费者---注册消费者
		disruptor.handleEventsWith(new LongEventHandler());
		disruptor.handleEventsWith(new LongEventHandler2());
		// 多个消费者 一个生产者 默认重复消费、配置分组
		// 6.启动
		disruptor.start();
		// 7.创建RingBuffer容器
		RingBuffer<LongEvent> ringBuffer = disruptor.getRingBuffer();
		// 8.创建生产者
		LongEventProducer producer = new LongEventProducer(ringBuffer);
		// 9.指定缓冲区大小
		ByteBuffer byteBuffer = ByteBuffer.allocate(8);
		for (int i = 1; i < 100; i++) {
			byteBuffer.putLong(0, i);
			producer.onData(byteBuffer);
		}
		executor.shutdown();
		disruptor.shutdown();
		
	}

}