Java中是否存在文件？

Question

I trying to check whether a file exists at given directory location.

File seacrhFile = new File("D:/input", contract.conf);
if (seacrhFile.exists()) {
  returnFile = seacrhFile;
} else {
  System.out.println("No such file exists");
}
reutrn returnFile;

This is working in D:/input directory scenario, but if I Change the directory location to src/test/resources/input folder then I am getting No such file exists , eventhough the file exists.

Answer 1

If you want to have access to
src/test/resources/input
you probably should use

System.getProperty("user.dir") + File.separator + "src/test/resources/input"

because the system-property "user.dir" points to the projectlocation.

If you just use "src/test/resources/input" you will get your mentioned exception, because the File Object don't "start" at the project location. So you have to specify it manually.

Nevertheless it's better to use the getResource-Method to retrieve different resources within your project, because if you run your project with the jar-File you need to tweak around to get "user.dir" to work correctly.

Just a basic example for the Classloader:

ClassLoader.getSystemClassLoader().getResource("test/resources/input");

This returns an URL-Object, with this object you can get the File-Object using ...

URL filePath =  ClassLoader.getSystemClassLoader().getResource("test/resources/input");
File file = new File( filePath.toURI() );

Answer 2

删除src，然后重试。