派生线程类[Java编程]

最简单的编写基于线程的代码的办法之一,就是派生java.lang.Thread 类.该线程类是java.lang 包的一个成员,在缺省情形下,线程类可以被全部的Java利用程序调用.为了利用线程类,我们需求理解The java.lang.Thread 类中定义的五个办法:

run():该办法用于线程的履行.你需求重载该办法,以便让线程做特定的工作.

start():该办法使得线程启动run().

stop():该办法同start办法的作用相反,终止线程的运行.

suspend():该办法同stop办法差别的是,它并不终止未完成的线程,它仅仅挂起线程,今后还可恢复.

resume():该办法重新启动已经挂起的线程.

运行List A中的程序,运行后果见List B

List A :扩大线程类

class TestThreads {
public static void main (String args []) {
class MyThread extends Thread {
String which;
MyThread (String which) {
this.which = which;
}
public void run() {
int iterations = (int)(Math.random()*100) %15;
int sleepinterval = (int)(Math.random()*1000);
System.out.println(which + " running for " + iterations +" iterations");
System.out.println(which + " sleeping for " + sleepinterval + "ms between loops");
for (int i = 0; < iterations; i++) {
System.out.println(which +" " + i);
try {
Thread.sleep(sleepinterval);
} catch (InterruptedException e) {}
}
}
}
MyThread a = new MyThread("Thread A");
MyThread b = new MyThread("Thread B");
MyThread c = new MyThread("Thread C");
a.start();
b.start();
c.start();
}
}
ListB: 清单A的输出
Thread A running for 16 iterations
Thread C running for 15 iterations
Thread B running for 14 iterations
Thread A sleeping for 305ms between
loops
Thread C sleeping for 836ms between
loops
Thread B sleeping for 195ms between
loops
Thread A 0
Thread C 0
Thread B 0
. . .
Thread C 13
Thread B 13
Thread A 14
Thread C 14
Thread A 15

List A演示了若何从现有的Thread类中派生出一个新类.新成立的类重载了run 办法.风趣的是,实现run 办法没必要很严峻,因为Thread类供应一个缺省的run办法,固然它不是分外有效.

在有些场所,我们不能简单地改变指定对象的父类.我们仍旧需求采取线程.这时,我们就需求用到Runnable接口.