如何并行运行不同的方法 [英] How to run different methods parallely

问题描述

我有一个Java方法，其中包含5种不同的内部方法.为了提高性能，我想并行调用这些方法.

I have one java method which contains 5 different internal methods. For performance improvement, I want to call these methods parallely.

例如使用线程并行运行method1，method2，... method5.

e.g. run method1, method2, ... method5 parallel using thread.

private void getInformation() throws SQLException,
            ClassNotFoundException, NamingException {
    method1();
    method2();
    method3();
    method4();
    method5();
}

但是所有这5种方法都有不同的业务逻辑.

but all these 5 methods have different business logic.

推荐答案

执行以下操作:

1. 对于每个方法，创建一个包装该方法的Callable对象.
2. 创建一个执行程序(固定线程池执行程序应该没问题).
3. 将所有可调用对象放入列表中，然后使用执行程序调用它们.

这是一个简单的例子:

public void testThread()
{

   //create a callable for each method
   Callable<Void> callable1 = new Callable<Void>()
   {
      @Override
      public Void call() throws Exception
      {
         method1();
         return null;
      }
   };

   Callable<Void> callable2 = new Callable<Void>()
   {
      @Override
      public Void call() throws Exception
      {
         method2();
         return null;
      }
   };

   Callable<Void> callable3 = new Callable<Void>()
   {
      @Override
      public Void call() throws Exception
      {
         method3();
         return null;
      }
   };

   //add to a list
   List<Callable<Void>> taskList = new ArrayList<Callable<Void>>();
   taskList.add(callable1);
   taskList.add(callable2);
   taskList.add(callable3);

   //create a pool executor with 3 threads
   ExecutorService executor = Executors.newFixedThreadPool(3);

   try
   {
      //start the threads and wait for them to finish
      executor.invokeAll(taskList);
   }
   catch (InterruptedException ie)
   {
      //do something if you care about interruption;
   }

}

private void method1()
{
   System.out.println("method1");
}

private void method2()
{
   System.out.println("method2");
}

private void method3()
{
   System.out.println("method3");
}

确保每个方法都不共享状态(如同一类中的公共可变字段)，否则您可能会得到意想不到的结果. Oracle提供了关于Java执行器的很好的介绍.另外，如果您正在做任何事情，这本书很棒Java中的线程.

Make sure each method does not share state (like a common mutable field in the same class) or you may get unexpected results. Oracle provides a good introduction to Java Executors. Also, this book is awesome if you are doing any kind of threading in java.

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