线程池有哪些配置参数,各自的作用是什么?
5大参数
a.核心线程数
b 最大线程数
c 线程空闲时间
d 阻塞队列大小:queueCapacity
e 任务拒绝处理器 :rejectedExceptionHandler
根据jdk 1.7,他又四类构造函数:
1. ThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue)
2. ThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue, RejectedExecutionHandler handler)
3. ThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue, ThreadFactory threadFactory)
4. ThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue, ThreadFactory threadFactory, RejectedExecutionHandler handler)
实现线程池,有四种策略:
1.newCachedThreadPool
jdk 1.6源码:
public static ExecutorService newCachedThreadPool() {
return new ThreadPoolExecutor(0, Integer.MAX_VALUE,
60L, TimeUnit. SECONDS,
new SynchronousQueue<Runnable>());
}
2 newFixedThreadPool
jdk 1.6源码:
public static ExecutorService newFixedThreadPool(int nThreads) {
return new ThreadPoolExecutor(nThreads, nThreads,
0L, TimeUnit. MILLISECONDS,
new LinkedBlockingQueue<Runnable>());
}
3 newSingleThreadExecutor
jdk 1.6源码:
public static ExecutorService newSingleThreadExecutor() {
return new FinalizableDelegatedExecutorService
( new ThreadPoolExecutor(1, 1,
0L, TimeUnit. MILLISECONDS,
new LinkedBlockingQueue<Runnable>()));
}
4 newScheduledThreadPool
jdk 1.6源码:
public static ScheduledExecutorService newScheduledThreadPool (int corePoolSize) {
return new ScheduledThreadPoolExecutor(corePoolSize);
}
public ScheduledThreadPoolExecutor( int corePoolSize) {
super(corePoolSize, Integer.MAX_VALUE, 0, TimeUnit.NANOSECONDS,
new DelayedWorkQueue());
}