JAR文件中出现File Not Found Exception异常，已配置路径仍报错求助

Hey there, let's tackle this File Not Found Exception issue you're facing with your JAR file—even though you've placed it in the specified path, right? I've run into similar headaches before, so here are the most common fixes to check out:

• Check the actual file path your app is looking for
  Sometimes the path you think you're specifying isn't what the JAR is using. When you run a JAR, the working directory might not match the JAR's location. Try printing the absolute path your code is trying to access to verify:

  File file = new File("your-specified-path.txt");
  System.out.println("Attempting to access: " + file.getAbsolutePath());
  

  This will show you exactly where the app is trying to look, which might not align with where you placed the file.

• Ensure the file is included in the JAR (if it's an internal resource)
  If the file is supposed to be bundled inside the JAR (not an external file), make sure your build tool (Maven, Gradle, etc.) is packaging it correctly. For example, in Maven, resources should live in src/main/resources—files outside this folder won't get added to the JAR. Also, use the right method to load internal resources:

  InputStream input = getClass().getClassLoader().getResourceAsStream("path/inside/jar/file.txt");
  if (input == null) {
      throw new FileNotFoundException("Resource not found in JAR");
  }
  

  The File class won't work for resources inside the JAR because they aren't actual filesystem files.

• Verify file permissions
  Even if the file is in the right spot, your app might lack read access. On Linux/macOS, run ls -l to check permissions; on Windows, right-click the file > Properties > Security tab to confirm your user has read rights.

• Watch for typos and case sensitivity
  Filesystems like Linux are case-sensitive—MyFile.txt and myfile.txt are treated as different files. Double-check that the filename in your code matches the actual file exactly, including capitalization and extensions.

• Avoid issues with spaces or special characters in the path
  If your path has spaces (like C:\Program Files\myapp\file.txt), make sure you're handling them correctly. Use File.separator instead of hardcoding slashes to avoid escaping errors:

  String path = "C:" + File.separator + "Program Files" + File.separator + "myapp" + File.separator + "file.txt";
  File file = new File(path);
  

内容的提问来源于stack exchange，提问作者Fakkir mohamed Sait