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:
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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:
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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:
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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:
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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,如果大家有任何疑问请给我留言,小编会及时回复大家的。在此也非常感谢大家对网站的支持!
原文链接:https://blog.csdn.net/qq_43499096/article/details/89048216
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