多线程笔记

在创建线程池的时候不管你创建的是newFixedThreadPool，还是newCachedThreadPool，还是newSingleThreadPool
在里面调用的都是new ThreadPoolExecutor这个类，知识传入的参数值不同而已
实例：
public static ExecutorService newCachedThreadPool() {
return new ThreadPoolExecutor(0, Integer.MAX_VALUE,
60L, TimeUnit.SECONDS, new SynchronousQueue<Runnable>());
}

默认情况下，线程池中并没有任何线程，而是等待有任务到来才创建线程去执行任务

public class ThreadPoolExecutor extends AbstractExecutorService {

    .....

    public ThreadPoolExecutor(int corePoolSize,int maximumPoolSize,long keepAliveTime,TimeUnit unit,

            BlockingQueue<Runnable> workQueue);

 

    public ThreadPoolExecutor(int corePoolSize,int maximumPoolSize,long keepAliveTime,TimeUnit unit,

            BlockingQueue<Runnable> workQueue,ThreadFactory threadFactory);

 

    public ThreadPoolExecutor(int corePoolSize,int maximumPoolSize,long keepAliveTime,TimeUnit unit,

            BlockingQueue<Runnable> workQueue,RejectedExecutionHandler handler);

 

    public ThreadPoolExecutor(int corePoolSize,int maximumPoolSize,long keepAliveTime,TimeUnit unit,

        BlockingQueue<Runnable> workQueue,ThreadFactory threadFactory,RejectedExecutionHandler handler);

    ...

}