ThreadPoolExecutor线程池

1.ThreadPoolExecutor继承结构(具体可查API)

--Executor (interface)
    --ExecutorService (interface)
        --AbstractExecutorService (abstract class)
            --ThreadPoolExecutor

2.ThreadPoolExecutor常用API

2.1 线程池实例化方法，共4个这里看最复杂的一个

public ThreadPoolExecutor(int corePoolSize,
                          int maximumPoolSize,
                          long keepAliveTime,
                          TimeUnit unit,
                          BlockingQueue<Runnable> workQueue,
                          ThreadFactory threadFactory,
                          RejectedExecutionHandler handler);
corePoolSize：核心线程数
maximumPoolSize：最大线程数
keepAliveTime：回收空闲线程的时间（默认回收大于核心线程数的部分）
unit：回收空闲线程时间的单位
workQueue：缓存队列，缓存尚未执行的Runnable
threadFactory：线程创建工程
handler：拒绝处理任务时的策略

2.2 execute执行线程

void execute(Runnable command);

2.3 shutdown执行完所有任务 关闭线程池

void shutdown();

注意：具体每一个参数使用参考官方文档

3.看看如下的小栗子

public class ThreadPoolTest {
    public static void main(String[] args) {
        ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(2, 5, 1, TimeUnit.MINUTES, new LinkedBlockingDeque<>());
        for (int index = 0; index < 30; index ++) {
            threadPoolExecutor.execute(new Task(index));
        }
        threadPoolExecutor.shutdown();
    }
}

class Task implements Runnable {
    private int index;
    public Task(int index) {
        this.index = index;
    }
    @Override
    public void run() {
        System.out.println(index + "正在执行...");
        try {
            Thread.sleep(2000);
        } catch (Exception e) {
        }
        System.out.println(index + "执行结束...");
    }
}

4.一般来说我们不推荐直接使用ThreadPoolExecutor, 而是使用Executors创建线程池，例如

public static ExecutorService newSingleThreadExecutor();
public static ExecutorService newFixedThreadPool(int nThreads, ThreadFactory threadFactory);
public static ExecutorService newCachedThreadPool();

5.总结

线程池还有很多其他的API，也就不一一介绍，有空还是要多看看源码和API文档

源码地址：https://gitee.com/jsjack_wang/JavaDemo

推荐博客：http://www.importnew.com/19011.html