Java多线程

         Java线程是Thread类的对象，可以使用两种方式来创建多线程的Java应用程序，如下所示：

（1）实现Runnable接口

（2）继承Thread类

         两种方式，都要在线程类的内部实现run()方法，然后new一个Thread，最后.start()。

1、Runnable接口的实现

package runnable;

public class RunnableTest {
private int length;

public RunnableTest(int length) {
this.length = length;
}

public long sum() {

long ret = 0;
for(int i=0;i<length; i++)
ret = ret+i;
return ret;
}

}

package runnable;

public class RunnableExtend extends RunnableTest implements Runnable {

public RunnableExtend(int length) {
super(length);
}

@Override
public void run() {
long sum = sum();
System.out.println(Thread.currentThread() + " sum =" + sum);
}

}

package runnable;

public class Main {
public static void main(String[] args) {
System.out.println("Thread is " + Thread.currentThread());

RunnableExtend mRunnableTestThread1 = new RunnableExtend(80);
Thread th1 = new Thread(mRunnableTestThread1, "th1");
th1.start();

RunnableExtend mRunnableTestThread2 = new RunnableExtend(140);
Thread th2 = new Thread(mRunnableTestThread2, "th2");
th2.start();
}
}

2、Thread类
package thread;

public class ThreadTest extends Thread {
private int length;

public ThreadTest(int length) {
this.length = length;
}

public long sum() {

long ret = 0;
for(int i=0;i<length; i++)
ret = ret+i;
return ret;
}

public void run() {
long sum = sum();
System.out.println(Thread.currentThread() + " sum =" + sum);
}
}

package thread;

public class Main {
public static void main(String[] args) {
System.out.println("Thread is " + Thread.currentThread());
//直接继承，创建线程
ThreadTest mThreadTest1 = new ThreadTest(80);
Thread th1 = new Thread(mThreadTest1, "th1");
th1.start();

//使用匿名类创建
new Thread("th2"){
int length = 190;
public void run(){
int ret = 0;
for(int i=0;i<length; i++)
ret = ret+i;
System.out.println(Thread.currentThread() + " sum =" + ret);
}
}.start();
}
}