How to save generated file temporarily in servlet based web application
I am trying to generate a XML file and save it in /WEB-INF/pages/.
Below is my code which uses a relative path:
File folder = new File("src/main/webapp/WEB-INF/pages/"); StreamResult result = new StreamResult(new File(folder, fileName));
It's working fine when running as an application on my local machine (C:\Users\userName\Desktop\Source\MyProject\src\main\webapp\WEB-INF\pages\myFile.xml).
But when deploying and running on server machine, it throws the below exception:
javax.xml.transform.TransformerException: java.io.FileNotFoundException C:\project\eclipse-jee-luna-R-win32-x86_64\eclipse\src\main\webapp\WEB INF\pages\myFile.xml
I tried getServletContext().getRealPath() as well, but it's returning null on my server. Can someone help?
Never use relative local disk file system paths in a Java EE web application such as new File("filename.xml"). For an in depth explanation, see also getResourceAsStream() vs FileInputStream.
Never use getRealPath() with the purpose to obtain a location to write files. For an in depth explanation, see also What does servletcontext.getRealPath("/") mean and when should I use it.
Never write files to deploy folder anyway. For an in depth explanation, see also Recommended way to save uploaded files in a servlet application.
Always write them to an external folder on a predefined absolute path.
File folder = new File("/absolute/path/to/web/files"); File result = new File(folder, "filename.xml"); // ...
Or configured in one of many ways:
File folder = new File(System.getProperty("xml.location")); File result = new File(folder, "filename.xml"); // ...
Or making use of container-managed temp folder:
File folder = (File) getServletContext().getAttribute(ServletContext.TEMPDIR); File result = new File(folder, "filename.xml"); // ...
Or making use of OS-managed temp folder:
File result = File.createTempFile("filename-", ".xml"); // ...
The alternative is to use a (embedded) database.
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File relpath = new File(".\pages\");
as application cursor in default stay into web-inf folder.