详解多线程及Runable 和Thread的区别

thread和runnable区别

执行多线程操作可以选择
继承thread类
实现runnable接口

1.继承thread类

以卖票窗口举例，一共5张票，由3个窗口进行售卖(3个线程)。
代码：

package thread;
public class threadtest {
	public static void main(string[] args) {
		mythreadtest mt1 = new mythreadtest("窗口1");
		mythreadtest mt2 = new mythreadtest("窗口2");
		mythreadtest mt3 = new mythreadtest("窗口3");
		mt1.start();
		mt2.start();
		mt3.start();
	}
}
class mythreadtest extends thread{
	private int ticket = 5;  
	private string name;
	public mythreadtest(string name){
		this.name = name;
	}
  public void run(){  
     while(true){ 
       if(ticket < 1){  
        break; 
       }  
       system.out.println(name + " = " + ticket--);  
     }  
  } 
}

执行结果：
窗口1 = 5
窗口1 = 4
窗口1 = 3
窗口1 = 2
窗口1 = 1
窗口2 = 5
窗口3 = 5
窗口2 = 4
窗口3 = 4
窗口3 = 3
窗口3 = 2
窗口3 = 1
窗口2 = 3
窗口2 = 2
窗口2 = 1
结果一共卖出了5*3=15张票，这违背了"5张票"的初衷。
造成此现象的原因就是：

mythreadtest mt1 = new mythreadtest("窗口1");
	mythreadtest mt2 = new mythreadtest("窗口2");
	mythreadtest mt3 = new mythreadtest("窗口3");
	mt1.start();
	mt2.start();
	mt3.start();

一共创建了3个mythreadtest对象，而这3个对象的资源不是共享的，即各自定义的ticket=5是不会共享的，因此3个线程都执行了5次循环操作。

2.实现runnable接口

同样的例子，代码：

package thread;
public class runnabletest {
	public static void main(string[] args) {
		myrunnabletest mt = new myrunnabletest();
		thread mt1 = new thread(mt,"窗口1");
		thread mt2 = new thread(mt,"窗口2");
		thread mt3 = new thread(mt,"窗口3");
		mt1.start();
		mt2.start();
		mt3.start();
	}
}
class myrunnabletest implements runnable{
	private int ticket = 5;  
	public void run(){  
     while(true){ 
  		 if(ticket < 1){  
  			 break; 
  		 }  
  		 system.out.println(thread.currentthread().getname() + " = " + ticket--);  
     }  
  } 
}

结果：

窗口1 = 5
窗口1 = 2
窗口3 = 4
窗口2 = 3
窗口1 = 1

结果卖出了预期的5张票。
原因在于：

myrunnabletest mt = new myrunnabletest();
thread mt1 = new thread(mt,"窗口1");
thread mt2 = new thread(mt,"窗口2");
thread mt3 = new thread(mt,"窗口3");
mt1.start();
mt2.start();
mt3.start();

只创建了一个myrunnabletest对象，而3个thread线程都以同一个myrunnabletest来启动，所以他们的资源是共享的。

以上所述是小编给大家介绍的多线程及runable 和thread的区别详解整合，希望对大家有所帮助