同时启动多个线程 [英] Starting multiple thread at the same time

问题描述

我一直在试图写一些java应用程序。
这个应用程序想要运行的是处理一个文本文件。

但是，输入文本文件很大（超过200mb）
分割200mb为四个拆分文件（每个50mb）

然后，使用四个线程尝试同时处理每个拆分。

所以，我做一个类实现runnable，它有一个文本过程模块。
然后，我使4 obj的（命名worker1〜worker4）runnnable类然后调用：

  worker1.run （）; 
 worker2.run（）; 
 worker3.run（）; 
 worker4.run（）; 
  

但是，这些线程不是同时运行，而是线性运行。
这意味着，在worker 1线程完成后，worker2线程正在运行。

因此，每个线程只需0.5秒， ，每个花费2秒。 （worker1为0.5s，worker2为0.5s，worker3为0.5s，worker4为0.5s）
如果我可以同时运行4个线程，我预计这个应用程序只需要0.5秒或者小于1秒

解决方案

您需要启动一个线程。所以：

  new Thread（worker1）.start（）; 
 new Thread（worker2）.start（）; 
 new Thread（worker3）.start（）; 
 new Thread（worker4）.start（）; 
  

I have been trying to write some java application. What this application wants to run is processing a text file.

However, that input text file is large, (over 200mb) I tried to split 200mb as four split files (50mb each)

Then, using four threads, tries to process each of split simultaneously.

So, I make a class which implements runnable, and it has a text process module. Then, I make 4 obj of that (named worker1 ~ worker4) runnnable class then call:

worker1.run();
worker2.run();
worker3.run();
worker4.run();

However, these threads are not running simultaneously, but running linearly. This means, after worker 1 thread is finished, then worker2 thread is running.

So, each of them takes just 0.5 sec, but with this linear running, It tooks 2 secs each. (0.5s for worker1 + 0.5s for worker2 + 0.5s for worker3 + 0.5s for worker4) If I can run 4 threads at the same time, I expected that this application takes just about 0.5 sec or less than 1 sec which is faster than 2 secs.

How can I do that?

解决方案

You need to start a thread. So:

new Thread(worker1).start();
new Thread(worker2).start();
new Thread(worker3).start();
new Thread(worker4).start();

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