newSingleThreadExecutor 方法

可以透過呼叫 Executors 類中 newSingleThreadExecutor() 靜態方法來獲取單個執行緒池。

語法

ExecutorService executor = Executors.newSingleThreadExecutor();

newSingleThreadExecutor 方法建立一次執行一個任務的執行器。

例項

以下 TestThread 程式展示了在基於執行緒的環境中使用 newSingleThreadExecutor 方法。

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

public class TestThread {

   public static void main(final String[] arguments) throws InterruptedException {
      ExecutorService executor = Executors.newSingleThreadExecutor();

      try {
         executor.submit(new Task());
         System.out.println("Shutdown executor");
         executor.shutdown();
         executor.awaitTermination(5, TimeUnit.SECONDS);
      } catch (InterruptedException e) {
         System.err.println("tasks interrupted");
      } finally {

         if (!executor.isTerminated()) {
            System.err.println("cancel non-finished tasks");
         }
         executor.shutdownNow();
         System.out.println("shutdown finished");
      }
   }

   static class Task implements Runnable {
      
      public void run() {

         try {
            Long duration = (long) (Math.random() * 20);
            System.out.println("Running Task!");
            TimeUnit.SECONDS.sleep(duration);
         } catch (InterruptedException e) {
            e.printStackTrace();
         }
      }
   }
}

它將產生以下結果。

輸出

Shutdown executor
Running Task!
shutdown finished
cancel non-finished tasks
java.lang.InterruptedException: sleep interrupted
	at java.lang.Thread.sleep(Native Method)
	at java.lang.Thread.sleep(Thread.java:302)
	at java.util.concurrent.TimeUnit.sleep(TimeUnit.java:328)
	at TestThread$Task.run(TestThread.java:39)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:439)
	at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
	at java.util.concurrent.FutureTask.run(FutureTask.java:138)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
	at java.lang.Thread.run(Thread.java:662)