【并发编程】- 线程池使用execute、submit方法对异常处理

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2. execute()出现异常后直接输出堆栈信息，而submit()方法可以捕获异常继续

   运行类代码如下：

   public class ExecuteExceptionRun {
       public static void main(String[] args) {
           ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(2, 5, 10, TimeUnit.SECONDS, new LinkedBlockingQueue<Runnable>());
           threadPoolExecutor.execute(
                   new Runnable() {
                       @Override
                       public void run() {
                           Integer.parseInt("A");
                       }
                   }
           );
       }
   }
   

   运行结果如下：

   Exception in thread "pool-1-thread-1" java.lang.NumberFormatException: For input string: "A"

   at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65) at java.lang.Integer.parseInt(Integer.java:580) at java.lang.Integer.parseInt(Integer.java:615) at com.ozx.concurrentprogram.executor.controller.ExecuteExceptionRun$1.run(ExecuteExceptionRun.java:20) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748)

   从运行结果看出execute()方法直接抛出异常而不能捕获到异常。

   修改运行类代码如下：

   @Slf4j
   public class ExecuteExceptionRun {
       public static void main(String[] args) {
           ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(2, 5, 10, TimeUnit.SECONDS, new LinkedBlockingQueue<Runnable>());
   
           Future<String> future = threadPoolExecutor.submit(new Callable<String>() {
               @Override
               public String call() throws Exception {
                   Integer.parseInt("A");
                   return String.valueOf(System.currentTimeMillis());
               }
           });
           try {
               log.info(future.get());
           } catch (InterruptedException e) {
               e.printStackTrace();
           } catch (ExecutionException e) {
               log.error("Callable能捕获到异常");
               e.printStackTrace();
           }
   
           threadPoolExecutor.execute(
                   new Runnable() {
                       @Override
                       public void run() {
                           Integer.parseInt("A");
                       }
                   }
           );
       }
   }
   

   运行结果如下：

   16:25:05.473 [main] ERROR com.ozx.concurrentprogram.executor.controller.ExecuteExceptionRun - Callable能捕获到异常

   java.util.concurrent.ExecutionException: java.lang.NumberFormatException: For input string: "A" at java.util.concurrent.FutureTask.report(FutureTask.java:122) at java.util.concurrent.FutureTask.get(FutureTask.java:192) at com.ozx.concurrentprogram.executor.controller.ExecuteExceptionRun.main(ExecuteExceptionRun.java:26)

   Caused by: java.lang.NumberFormatException: For input string: "A" at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65) at java.lang.Integer.parseInt(Integer.java:580) at java.lang.Integer.parseInt(Integer.java:615) at com.ozx.concurrentprogram.executor.controller.ExecuteExceptionRun$1.call(ExecuteExceptionRun.java:21) at com.ozx.concurrentprogram.executor.controller.ExecuteExceptionRun$1.call(ExecuteExceptionRun.java:18) at java.util.concurrent.FutureTask.run$$$capture(FutureTask.java:266) at java.util.concurrent.FutureTask.run(FutureTask.java) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748) Exception in thread "pool-1-thread-2" java.lang.NumberFormatException: For input string: "A" at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65) at java.lang.Integer.parseInt(Integer.java:580) at java.lang.Integer.parseInt(Integer.java:615) at com.ozx.concurrentprogram.executor.controller.ExecuteExceptionRun$2.run(ExecuteExceptionRun.java:38) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748)

   从运行结果看出线程池执行submit()方法出现异常，能被捕获到相关异常。