ThreadPoolExecutor（ThreadPoolExecutor）

java.util.concurrent.ThreadPoolExecutor是一个ExecutorService，它使用可能的几个池化线程之一执行每个提交的任务，通常使用Executors工厂方法配置。 它还提供各种实用程序方法来检查当前线程统计信息并控制它们。

ThreadPoolExecutor方法

例子 (Example)

以下TestThread程序显示了基于线程的环境中ThreadPoolExecutor接口的用法。

import java.util.concurrent.Executors;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
public class TestThread {
   public static void main(final String[] arguments) throws InterruptedException {
      ThreadPoolExecutor executor = (ThreadPoolExecutor)Executors.newCachedThreadPool();
      //Stats before tasks execution
      System.out.println("Largest executions: "
         + executor.getLargestPoolSize());
      System.out.println("Maximum allowed threads: "
         + executor.getMaximumPoolSize());
      System.out.println("Current threads in pool: "
         + executor.getPoolSize());
      System.out.println("Currently executing threads: "
         + executor.getActiveCount());
      System.out.println("Total number of threads(ever scheduled): "
         + executor.getTaskCount());
      executor.submit(new Task());
      executor.submit(new Task());
      //Stats after tasks execution
      System.out.println("Core threads: " + executor.getCorePoolSize());
      System.out.println("Largest executions: "
         + executor.getLargestPoolSize());
      System.out.println("Maximum allowed threads: "
         + executor.getMaximumPoolSize());
      System.out.println("Current threads in pool: "
         + executor.getPoolSize());
      System.out.println("Currently executing threads: "
         + executor.getActiveCount());
      System.out.println("Total number of threads(ever scheduled): "
         + executor.getTaskCount());
      executor.shutdown();
   }  
   static class Task implements Runnable {
      public void run() {
         try {
            Long duration = (long) (Math.random() * 5);
            System.out.println("Running Task! Thread Name: " +
               Thread.currentThread().getName());
            TimeUnit.SECONDS.sleep(duration);
            System.out.println("Task Completed! Thread Name: " +
               Thread.currentThread().getName());
         } catch (InterruptedException e) {
            e.printStackTrace();
         }
      }
   }
}

这将产生以下结果。

输出 (Output)

Largest executions: 0
Maximum allowed threads: 2147483647
Current threads in pool: 0
Currently executing threads: 0
Total number of threads(ever scheduled): 0
Core threads: 0
Largest executions: 2
Maximum allowed threads: 2147483647
Current threads in pool: 2
Currently executing threads: 2
Total number of threads(ever scheduled): 2
Running Task! Thread Name: pool-1-thread-2
Running Task! Thread Name: pool-1-thread-1
Task Completed! Thread Name: pool-1-thread-1
Task Completed! Thread Name: pool-1-thread-2