线程池
JAVA类库提供了许多静态方法来创建一个县城池。
- public static ExecutorService newCachedThreadPool()；
- public static ExecutorService newSingleThreadExecutor()；
- public static ExecutorService newFixedThreadPool(int paramInt)；
- public static ScheduledExecutorService newScheduledThreadPool(int paramInt)；
package com.falshhold.main;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
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 ThreadDemo {
public static void main(String[] args) {
// 线程个数固定
//ExecutorService threadPool = Executors.newFixedThreadPool(5);
//一个线程执行操作
//ExecutorService threadPool = Executors.newSingleThreadExecutor();
// List<Future<String>> resultList = new ArrayList<Future<String>>();
// 线程定时完成操作
// ScheduledThreadPoolExecutor threadPool = (ScheduledThreadPoolExecutor) Executors.newScheduledThreadPool(10);
ExecutorService threadPool = Executors.newCachedThreadPool();
for(int i = 0; i < 10; i++) {
Future<String> future=threadPool.submit(new Callable<String>() {
@Override
public String call() throws Exception {
// TODO Auto-generated method stub
//int cpuNums = Runtime.getRuntime().availableProcessors();
//System.out.println(cpuNums);
for (int i = 999999; i > 0; i--) ;
System.out.println("call()方法被自动调用,干活！！！ " + Thread.currentThread().getName());
//Thread.sleep(1000);
return "call()方法被自动调用，任务的结果是： " + Thread.currentThread().getName();
}
});
resultList.add(future);
}
threadPool.shutdown(); //执行到此处并不会马上关闭线程池,但之后不能再往线程池中加线程，否则会报错
System.out.println("Main: Finished all threads at"+ new Date());
for (Future<String> fs : resultList) {
try {
System.out.println(fs.get()); //打印各个线程（任务）执行的结果
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
} finally {
}
}
/* threadPool.submit(new Callable<String>() {
@Override
public String call() throws Exception {
// TODO Auto-generated method stub
//int cpuNums = Runtime.getRuntime().availableProcessors();
//System.out.println(cpuNums);
System.out.println(Thread.currentThread().getName()+new Date());
Thread.sleep(1000);
return "hahahahha";
}
});*/
}
}
submit()和excute()方法的区别，
submit执行带返回值，excute没有返回值。