java线程及操作实例，线程池简单例子

标签：java   线程   多线程   同步   线程池   

    java io、集合、线程、字符串、gc、jvm可谓是java中的最基本的知识，尤其是线程操作复杂，相应难懂，要想java基础知识扎实，上面提到的几个方面的知识点都要精通，这样方可以称自己掌握java方面基础知识。

    总结一下java线程知识，平时接触过线程，尤其是在android开发中，线程可谓是无处不在，稍有不注意就会报错。在java中线程也是无处不在，main就是一个线程，只不过被包装好了，一般接触不到。

    我的无数次的复习经历告诉我，学习知识最快，最深刻的方法就是从解题开始，不要先看概念，遇到新知识点，新概念先自己用已有的原始知识解一遍，然后再去看相关解释，会发现，概念是那么的浅显易懂。废话不多说，先上题：

    1.用两个线程，交叉输出“123...56”和“abc...z”，要求输出结果为“12a34b67c...5556z”。

    分析：此题用到线程同步互斥的知识点。线程1输出->唤醒线程2->线程1等待，线程2输出->唤醒线程1->线程2等待...一直到输出完毕。本题几乎可以全面考察线程互斥的知识。有了这些分析就可以上代码：

/**
 * 
 * @author mxr
 *ClassName ThreadTest 
 *@Version 1.0
 *@ModifiedBy 2014-10-27
 *@Copyright RSDSYST
 */
public class ThreadTest extends Thread {

	 class Thread1 implements Runnable {
		 private Object _lock;

		 public Thread1(Object lock) {
		  _lock = lock;
		 }

		 @Override
		 public void run() {
		  try {
		   synchronized (_lock) {
		    for (int i = 0; i < 26; i++) {
		     System.out.print((2 * i + 1) + "" + (2 * i + 2));
		     _lock.notifyAll();//唤醒其他线程
		     _lock.wait();//释放锁,等待
		    }
		   }
		  } catch (InterruptedException e) {
		   e.printStackTrace();
		  }
		 }

		}


		 class Thread2 implements Runnable {
		 private Object _lock;

		 public Thread2(Object lock) {
		  _lock = lock;
		 }

		 @Override
		 public void run() {
		  synchronized (_lock) {
		   for (int i = 0; i < 26; i++) {
		    System.out.print((char) ('a' + i));
		    _lock.notifyAll();//叫醒其他线程
		    if(i<25){
		    	try {
					_lock.wait();//释放锁，等待
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
		    }
		    
		   }
		  }
		 }

		}

		 public static void main(String[] args){
		  Object lock=new Object();
		  Thread t1=new Thread(new ThreadTest().new Thread1(lock));
		  Thread t2=new Thread(new ThreadTest().new Thread2(lock));
		  t1.start();
		  t2.start();
		  try {
		   t1.join();
		   t2.join();
		  } catch (InterruptedException e) {
		   e.printStackTrace();
		  }
		 }

}

2.用线程实现银行取钱问题，当出现错误时，如何进行同步。

/**
 * 
 * @author mxr
 *ClassName ThreadTest 
 *@Version 1.0
 *@ModifiedBy 2014-10-27
 *@Copyright RSDSYST
 */
class User{
	int sumCount = 100;
	User(){}
	public <span style="color:#ff0000;">synchronized</span> void  oper(int count){
		sumCount = sumCount - count;
		System.out.println(" has get: "+count+". the sumCount is: "+sumCount);
	}
}
public class ThreadTest extends Thread {
	User user;
	int useCount;
    ThreadTest(User user,int useCount){
    	this.user = user;
    	this.useCount = useCount;
    }
	public void run(){
		
			try {
				sleep(10);
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			user.oper(useCount);

	}

	 public static void main(String[] args){
		 System.out.println(Thread.currentThread().getName()+" is running");
		 User user = new User();
		 ThreadTest tt = new ThreadTest(user,30);
		 ThreadTest tt1 = new ThreadTest(user,20);
		 ThreadTest tt2 = new ThreadTest(user,30);
		 ThreadTest tt3 = new ThreadTest(user,10);
		 tt.start();
		 tt1.start();
		 tt2.start();
		 tt3.start();
		 System.out.println(Thread.currentThread().getName()+" is end");
	  
		 
	 }

}

3.简单的对线程池的理解和应用。

    线程池用ExecutorService和Executors来建立，为程序提供线程，当线程很多时，可以大大的节省内存空间，线程池是一个线程队列，当队列的容量小时，多出来的线程就会排队等待。

    用容量为2的线程池来实现银行取款问题：

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

/**
 * 
 * @author mxr
 *ClassName ThreadTest 
 *@Version 1.0
 *@ModifiedBy 2014-10-27
 *@Copyright RSDSYST
 */
class User{
	int sumCount = 100;
	User(){}
	public <span style="color:#ff0000;">synchronized</span> void  oper(int count){
		sumCount = sumCount - count;
		System.out.println(" has get: "+count+". the sumCount is: "+sumCount);
	}
}
public class ThreadTest extends Thread {
	User user;
	int useCount;
    ThreadTest(User user,int useCount){
    	this.user = user;
    	this.useCount = useCount;
    }
	public void run(){
		
			try {
				sleep(30);
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			user.oper(useCount);

	}

	 public static void main(String[] args){
		 System.out.println(Thread.currentThread().getName()+" is running");
		 User user = new User();
		 ThreadTest tt = new ThreadTest(user,30);
		 ThreadTest tt1 = new ThreadTest(user,20);
		 ThreadTest tt2 = new ThreadTest(user,30);
		 ThreadTest tt3 = new ThreadTest(user,10);
		 ExecutorService pool = Executors.newFixedThreadPool(4);
		 pool.execute(tt);
		 pool.execute(tt1);
		 pool.execute(tt2);
		 pool.execute(tt3);
		 System.out.println(Thread.currentThread().getName()+" is end");
	  
		 
	 }

}

java线程及操作实例，线程池简单例子

标签：java   线程   多线程   同步   线程池   

原文地址：http://blog.csdn.net/renxyz/article/details/40506279