Executors類裏邊常用的四種線程池
public class Executors {
//1.newFixedThreadPool
創建一個定長線程池，可控制線程最大併發數，超出的線程會在無界隊列中等待
public static ExecutorService newFixedThreadPool(int nThreads) {
return new ThreadPoolExecutor(nThreads, nThreads,
0L, TimeUnit.MILLISECONDS,
new LinkedBlockingQueue<Runnable>());
}
//2.newSinglethreadExecutor
創建一個單線程化的線程池，它只會用唯一的工作線程來執行任務，保證所有的任務按照指定的順序(FIFO，LIFO，優先級)執行
public static ExecutorService newSingleThreadExecutor() {
return new FinalizableDelegatedExecutorService
(new ThreadPoolExecutor(1, 1,
0L, TimeUnit.MILLISECONDS,
new LinkedBlockingQueue<Runnable>()));
}
//3.newCachedThreadPool
創建一個可緩存線程池，如果線程池超過處理需要，可靈活回收空閒線程，若無回收線程，則新建線程
public static ExecutorService newCachedThreadPool() {
return new ThreadPoolExecutor(0, Integer.MAX_VALUE,
60L, TimeUnit.SECONDS,
new SynchronousQueue<Runnable>());
}
public static ExecutorService newCachedThreadPool(ThreadFactory threadFactory) {
return new ThreadPoolExecutor(0, Integer.MAX_VALUE,
60L, TimeUnit.SECONDS,
new SynchronousQueue<Runnable>(),
threadFactory);
}
//4.newScheduledThreadPool
創建一個定長線程池，支持定時及週期性任務執行
public static ScheduledExecutorService newScheduledThreadPool(int corePoolSize) {
return new ScheduledThreadPoolExecutor(corePoolSize);
}
}
//四種線程池其實內部方法都是調用的ThreadPoolExecutor類，只不過利用了其不同的構造方法而已（傳入自己需要傳入的參數），那麼利用這個特性，我們自己也是可以實現自己定義的線程池
}