线程池七大参数解析

先展示一下jdk8中ThreadPoolExecutor构造方法的源码

public ThreadPoolExecutor(int corePoolSize,
                          int maximumPoolSize,
                          long keepAliveTime,
                          TimeUnit unit,
                          BlockingQueue<Runnable> workQueue,
                          ThreadFactory threadFactory,
                          RejectedExecutionHandler handler) {
    if (corePoolSize < 0 ||
        maximumPoolSize <= 0 ||
        maximumPoolSize < corePoolSize ||
        keepAliveTime < 0)
        throw new IllegalArgumentException();
    if (workQueue == null || threadFactory == null || handler == null)
        throw new NullPointerException();
    this.acc = System.getSecurityManager() == null ?
            null :
            AccessController.getContext();
    this.corePoolSize = corePoolSize;
    this.maximumPoolSize = maximumPoolSize;
    this.workQueue = workQueue;
    this.keepAliveTime = unit.toNanos(keepAliveTime);
    this.threadFactory = threadFactory;
    this.handler = handler;
}

corePoolSize　　　　//核心线程数量，会一直存在，除非allowCoreThreadTimeOut设置为true
maximumPoolSize　　//线程池允许的最大线程池数量
keepAliveTime　　　//线程数量超过corePoolSize，空闲线程的最大超时时间
unit　　　　　　　　//超时时间的单位
workQueue　　　　　//工作队列，保存未执行的Runnable 任务
threadFactory　　 //创建线程的工厂类
handler　　　　　　//当线程已满，工作队列也满了的时候，会被调用。被用来实现各种拒绝策略。