java多线程

Thread创建的两种方式

实现runnable接口，实现run()方法

继承Thread类

ExecutorService类，Callable接口和Future对象

上面两种方式执行完任务是没有返回值的，如果想要任务返回值，需要实现callable接口中的call()方法，利用线程池执行时返回Future对象

import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;

public class ThreadTest {

/**
* @param args
* @throws ExecutionException
* @throws InterruptedException
*/
@SuppressWarnings("unchecked")
public static void main(String[] args) throws InterruptedException, ExecutionException {
// TODO Auto-generated method stub
ExecutorService pool=Executors.newFixedThreadPool(2);

ThreadTest test=new ThreadTest();

pool.execute(test.new runnable());

pool.execute(test.new thread());//execute()参数只能是Runnable

Future result=pool.submit(test.new callable());//submit()参数可以是Runnable，Callable
System.out.println(result.get().toString());

pool.shutdown();

}

class runnable implements Runnable
{

@Override
public void run() {
// TODO Auto-generated method stub
System.out.println("thread created by implements runnnable");
}

}

class callable implements Callable
{

@Override
public Object call() throws Exception {
// TODO Auto-generated method stub
System.out.println("task created by implements callable");
return "return value from callable";
}

}

class thread extends Thread
{
public void run()
{
System.out.println("thread created by extending Thread");
}

}

}