多线程基础

标签：多线程   thread   

线程是一个程序内部的顺序控制流。

当一个线程锁定了一个方法的时候，其他线程可以通过其他方法修改值，所以，一定要保证所有有关这个变量的方法都要加锁。

同步实例：

<span style="font-family:Microsoft YaHei;"><span style="font-size:12px;">package thread;

public class TT implements Runnable{

	int b = 100 ;
	
	@Override
	public void run() {
		m1() ;
	}
	
	//只会锁定m1方法内的内容，不会锁定b
	public synchronized void m1() {
		b = 1000 ;
		try {
			Thread.sleep(5000);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
		System.out.println("b = " + b);
	}

	public void m2() {
		System.out.println(b);
	}
	
	public static void main(String[] args) {
		TT t = new TT() ;
		Thread thread = new Thread(t) ;
		thread.start() ;
		try {
			Thread.sleep(1000);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
		t.m2();
	}
}
</span></span>

生产者与消费者实例：

<span style="font-family:Microsoft YaHei;">package thread;

public class ProducerConsumer {

	public static void main(String[] args) {
		SyncStack ss = new SyncStack() ;
		Producer p = new Producer(ss) ;
		Consumer c = new Consumer(ss) ;
		new Thread(p).start();
		new Thread(c).start();
	}
}

class WoTou {
	int id ;
	WoTou(int id) {
		this.id = id ;
	}
	public String toString() {
		return "id = " + this.id ;
	}
}

class SyncStack {
	int index = 0 ;
	WoTou[] arrWt = new WoTou[6] ;
	
	public synchronized void push(WoTou wt) {
		while(index == arrWt.length) {
			try {
				this.wait();
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		this.notify();
		arrWt[index] = wt ;
		index ++ ;
	}
	
	public synchronized WoTou pop() {
		while(index == 0) {
			try {
				this.wait();
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
		this.notify();
		index -- ;
		return arrWt[index] ;
	}
}

class Producer implements Runnable {
	
	SyncStack s = null ;
	
	public Producer(SyncStack s) {
		this.s = s ;
	}

	@Override
	public void run() {
		for(int i=0; i<20; i++) {
			WoTou wt = new WoTou(i) ;
			System.out.println("push : " + wt);
			s.push(wt);
		}
	}
}

class Consumer implements Runnable {
	
	SyncStack s = null ;
	
	public Consumer(SyncStack s) {
		this.s = s ;
	}

	@Override
	public void run() {
		for(int i=0; i<20; i++) {
			WoTou wt = s.pop() ;
			System.out.println("pop : " + wt);
		}
	}
}</span>

多线程基础

标签：多线程   thread   

原文地址：http://blog.csdn.net/benjamin_whx/article/details/44942293