How to get name of File object without its extensi

问题:

This question already has answers here:

How to get the filename without the extension in Java? (14 answers)

Closed 6 years ago.

I am trying to get name of a File object without its extension, e.g. getting "vegetation" when the filename is "vegetation.txt." I have tried implementing this code:

openFile = fileChooser.getSelectedFile();
String[] tokens = openFile.getName().split(".");
String name = tokens[0];

Unfortunately, it returns a null object. There is a problem just in the defining the String object, I guess, because the method getName() works correctly; it gives me the name of the file with its extension.

Do you have any idea?

回答1:

If you want to implement this yourself, try this:

String name = file.getName();
int pos = name.lastIndexOf(".");
if (pos > 0) {
    name = name.substring(0, pos);
}

(This variation doesn't leave you with an empty string for an input filename like ".txt". If you want the string to be empty in that case, change > 0 to >= 0.)

---

You could replace the if statement with an assignment using a conditional expression, if you thought it made your code more readable; see @Steven's answer for example. (I don't think it does ... but it is a matter of opinion.)

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It is arguably a better idea to use an implementation that someone else has written and tested. Apache FilenameUtils is a good choice; see @slachnick's Answer, and also the linked Q&A.

回答2:

If you don't want to write this code yourself you could use Apache's FilenameUtils.

FilenameUtils.getBaseName(openFile.getName());

This will return the filename minus the path and extension.

回答3:

I prefer to chop off before the last index of "." to be the filename. This way a file name: hello.test.txt is just hello.test

i.e.

int pos = filename.lastIndexOf(".");
String justName = pos > 0 ? filename.substring(0, pos) : filename;

You need to handle there being no extension too.

回答4:

String#split takes a regex. "." matches any character, so you're getting an array of empty strings - one for each spot in between each pair of characters.

http://docs.oracle.com/javase/6/docs/api/java/lang/String.html#split(java.lang.String)

回答5:

There are two problems with your code...

1) Just using "." as an argument to split is being interpreted as a Rejex that you don't want. You want a literal dot. So you have to escape it...

openFile.getName().split("\\.");

2) You will incorrectly parse any file with more than one dot. The best way to do this is to search for the last dot and get the substring...

int pos = openFile.getName().lastIndexOf(".");
if(pos != -1) {
   String name = openFile.getName().substring(0, pos);
}

回答6:

You can try split("\\.");. That is, basically escaping the . as it's treated as all characters in regex.