Java线程总结（二）

自定义线程的数据可以共享，也可以不共享，这要看具体的实现方式。

1.不共享数据多线程实现方式：

public class MyThread  extends Thread{
private int count = 4;

public MyThread(String threadName){
this.setName(threadName);
}

@Override
public void run(){
while (count > 0){
count = count - 1;
System.out.println("由 " + Thread.currentThread().getName() + " 计算，count = " + count);
try {
Thread.sleep(1000);
}catch (InterruptedException e){
e.printStackTrace();
}
}
}

public static void main(String[] args) {
MyThread threadA = new MyThread("A");
MyThread threadB = new MyThread("B");
MyThread threadC = new MyThread("C");
threadA.start();
threadB.start();
threadC.start();
}
}

执行结果如下：



从结果上看，每个线程都是都是先打印3，再打印2，然后是1，0。由此可知各个线程都有一份变量count，不受其他线程的干扰。

2. 共享数据的多线程实现方式

public class MyThread  extends Thread{
private int count = 4;

@Override
public void run(){
while (count > 0){
count = count - 1;
System.out.println("由 " + Thread.currentThread().getName() + " 计算，count = " + count);
try {
Thread.sleep(1000);
}catch (InterruptedException e){
e.printStackTrace();
}
}
}

public static void main(String[] args) {
MyThread myThread = new MyThread();
Thread a = new Thread(myThread,"A");
Thread b = new Thread(myThread,"B");
Thread c = new Thread(myThread,"C");
Thread d = new Thread(myThread,"D");
a.start();
b.start();
c.start();
d.start();
}
}

执行结果如下：



由结果可知，A，B，C，D四个线程共享变量count