线程（一）

 

class FirstThread extends Thread
{
	public void run(){
		for(int i=0;i<20;i++)
			System.out.println("FirstThread---->"+i);
	}
}

class Test
{
	public static void main(String args[]){
		//生成线程类对象
		FirstThread ft=new FirstThread();
		//启动线程，线程开始运行
		ft.start();
		 
		for(int i=0;i<20;i++)
			 System.out.println("main--->"+i);
	}
}

从结果看出，两个线程是交替着执行的；  

 

2.两种实现多线程的方法：继承Thread类，实现Runnable接口。

1）实现Thread类：

 

public class NumberThread extends Thread
{
	private int k;  //序列初始值
	public NumberThread(String name,int k){
		super(name);
		this.k=k;
	}
	public NumberThtead(String name){
		this(name,0);
	}
	public void run(){//覆盖run()方法的线程体
		int i=k;
		System.out.print("\n"+this.getName()+": ");
		while(i<50){
			System.out.print(i+" ");
			i+=2;
		}
		System.out.println(this.getName()+"结束");
	}

	public static void main(String args[]){
	    NumberThread thread_odd=new NumberThread("奇数线程",1);
		NumberThread thread_even=new NumberThread("偶数线程",2);
		thread_odd.start();
		thread_ever.start();
		System.out.println("activeCount="+thread_even.activeCount()); //返回当前活动线程个数
	}
}

 2）实现Runnable接口：

例1，

class RunnableImpl implements Runnable
{
	public void run(){
		for(int i=0;i<20;i++){
			System.out.println("Runnable--->"+i);
		}
	}
}

 

class Test
{
   public static void main(String args[])
   {
	//生成一个Runnable接口实现类的对象
	RunnableImpl ri=new RunnableImpl();
	//生成一个Thread对象，并将Runnable接口实现类的对象作为参数
	//传递给该Thread对象
	Thread t=new Thread(ri);
	//通知Thread对象，执行Start方法
	t.start();
    }
}

 

 

 

 

 

例2，

public class NumberRunnable implements Runnable
{
	private int k;
	public NumberRunnable(int k){
		this.k=k;
	}
	public NumberRunnable(){
		this(0);
	}
	public void run(){
		int i=k;
		System.out.println();
		while(i<50){
			System.out.print(i+" ");
			i+=2;
		}
		System.out.println("结束！");
	}
	public static void main(String args[]){
		NumberRunnable odd=new NumberRunnable(1);
		Thread thread_odd=new Thread(odd,"基数线程");
		thread_odd.start();
		new Thread(new NumberRunnable(2),"偶数线程").start();
	}
}