创建文件并存储在 Java Web 应用程序文件夹中
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Create a file and store in Java web application folder
提问by GigaPr
I would like to create an xml file and store in a folder within my spring Mvc web application.
我想创建一个 xml 文件并存储在我的 spring Mvc Web 应用程序中的一个文件夹中。
I can get the root of my application with request.getContextPath()
我可以得到我的应用程序的根 request.getContextPath()
but
但
how do i get the application's relative path so it will work on any machine indipendently by the location of the application's folder?
我如何获得应用程序的相对路径，以便它可以根据应用程序文件夹的位置在任何机器上独立运行？
Like C:/folder/folder/MYAPPLICATIONROOTFOLDER
喜欢 C:/folder/folder/MYAPPLICATIONROOTFOLDER
回答by Will Hartung
You want to do this.
你想这样做。
First, you need to get the ServletContext. I don't know how this is done in Spring MVC, but it's there somewhere.
首先，您需要获取 ServletContext。我不知道这是如何在 Spring MVC 中完成的，但它在某处。
Then you can do:
然后你可以这样做：
ServletContext ctx = getServletContextFromSpringSomehow();
String path = ctx.getRealPath("/folder/filename.txt");
FileWriter fw = new FileWriter(path);
The key here is ServletContext.getRealPath. It gives you the local file system path of a resource from within your webapp. Observer that you use "/" here, as it's a URL, not a file name. The container will give you a valid file name in return. Note, this only works if your container explodes your WAR, or you deploy an exploded WAR. If the WAR is NOT exploded, you will get a null back from the container.
这里的关键是 ServletContext.getRealPath。它为您提供 web 应用程序中资源的本地文件系统路径。观察者，您在这里使用“/”，因为它是一个 URL，而不是一个文件名。作为回报，容器会给你一个有效的文件名。请注意，这仅在您的容器爆炸 WAR 或部署爆炸 WAR 时才有效。如果 WAR 没有爆炸，您将从容器中获得一个空值。
Also note, this WILL work for non-existent files. The container does not check for the actual existence of the file. But it will be up to you to actually create any missing intermediate directories, etc.
另请注意，这将适用于不存在的文件。容器不检查文件的实际存在。但是实际创建任何丢失的中间目录等取决于您。
Finally, of course, that even if you get a file path back, doesn't mean you can actually write to that path. That's a OS permission issue outside of the scope of the container.
最后，当然，即使您返回文件路径，也不意味着您实际上可以写入该路径。这是容器范围之外的操作系统权限问题。
回答by dhable
One solution is to bundle the XML with the clases in the JAR/WAR and then use the getResourceAsStream() to leverage the ClassLoader to locate the file.
一种解决方案是将 XML 与 JAR/WAR 中的类捆绑在一起，然后使用 getResourceAsStream() 来利用 ClassLoader 来定位文件。
If I put the file foo.xml with the classes in com/stackoverflow/example, I could then locate the resources from objects in that bundle with
如果我将文件 foo.xml 与 com/stackoverflow/example 中的类一起放置，那么我可以从该包中的对象中找到资源
InputStream is = MyClass.getResourceAsStream( "com/stackoverflow/example" );
InputStream is = MyClass.getResourceAsStream( "com/stackoverflow/example" );
and from here process the file with a XML parser or whatever else you wanted to do to read the file.
并从这里使用 XML 解析器或其他任何您想要读取文件的方式处理文件。
