如何在Linux Ubuntu上用Java运行递归文件搜索？ [英] How do you run a recursive file search in Java on Linux Ubuntu?

问题描述

您好。我正在尝试在Java中运行递归文件搜索，以返回系统上所有.mp3文件的列表。现在，我的背景是在.NET中，我对Linux和Java都很新。我的目标是创建一个能够对我进行搜索的小型跨平台应用程序。在帐户上我需要从网站上启动应用程序，我认为我最好的选择是Java。无论如何，我根据我在线阅读的文章编写了代码。这是我目前的代码：

Hi. I''m trying to run a recursive file search in Java to return a list of all .mp3 files on the system. Now, my background is in .NET, and I''m fairly new to both Linux and Java. My goal is to create a small crossplatform app that is capable of doing this search for me. On the account I need the application to be launched from a website, I figured my best bet was Java. Anyway, I based the code I have now off an article I read online. This is my current code:

startSearch();

List<String> fs = new ArrayList<String>();
public void startSearch()
{

    File[] roots = File.listRoots();

    for(int i = 0; i < roots.length; i++)
    {
        File[] files = new File(roots[i].toString()).listFiles();
        getFiles(files);
    }

    JOptionPane.showMessageDialog(null, fs.get(0)); //This is just to test the function...

}

public void getFiles(File[] files)
{

    for(File file : files) ***
    {
        if(file.isDirectory())
        {
            getFiles(file.listFiles());
        }
        else
        {
            fs.add(file.toString());
        }
    }
}

然而，每当我运行它时，我得到上面一行上的以下错误，标有***：

However, whenever I run it I get the following error on the line above, marked with the ***:

java.lang.NullPointerException
	at Form1.getFiles(Form1.java:132)
	at Form1.getFiles(Form1.java:136)
	at Form1.startSearch(Form1.java:122)
	at Form1.initialize(Form1.java:111)
	at Form1.<init>(Form1.java:56)
	at Form1$1.run(Form1.java:42)
	at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:226)
	at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:673)
	at java.awt.EventQueue.access$300(EventQueue.java:96)
	at java.awt.EventQueue$2.run(EventQueue.java:634)
	at java.awt.EventQueue$2.run(EventQueue.java:632)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:105)
	at java.awt.EventQueue.dispatchEvent(EventQueue.java:643)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:275)
	at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:200)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:190)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:185)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:177)
	at java.awt.EventDispatchThread.run(EventDispatchThread.java:138)

任何想法是什么''错了？我认为它可能与事实有关，唯一的驱动器名称返回''/''并且它不知道在哪里看或什么的。我已经习惯了基于驱动的（C：/）文件系统。任何帮助，将不胜感激。在此先感谢！

Any ideas what''s wrong? I think it might have something to do with the fact the only drive name returned is ''/'' and it doesn''t know where to look or something. I''m so used to drive based (C:/) filesystems. Any help would be appreciated. Thanks in advance!

推荐答案

1.run（Form1.java:42）
at java.awt.event.InvocationEvent.dispatch（InvocationEvent.java： 226）
at java.awt.EventQueue.dispatchEventImpl（EventQueue.java:673）
at java.awt.EventQueue.access

1.run(Form1.java:42) at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:226) at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:673) at java.awt.EventQueue.access

300（EventQueue.java： 96）
at java.awt.EventQueue

300(EventQueue.java:96) at java.awt.EventQueue

2.run（EventQueue.java:634）
at java.awt.EventQueue

2.run(EventQueue.java:634) at java.awt.EventQueue

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