How to Check if a File is a Directory Using Java

Java


In this article, we show how to check if a file is a directory using Java.

Java views files and directories both as files. To Java, both regular files like text documents, pdfs, etc, and directories are all files.

To differentiate whether a file is a directory, Java has a built-in isDirectory() function.

This isDirectory() function checks to see whether a particular file is a directory or not.

The isDirectory() function normally isn't used standalone, meaning when you are checking a single file. It normally is used when you are looping through all the files in a certain directory and you want to see whether a particular file is a directory or a regular file.

For demonstration purposes, we show in this article how to check a single file and then you can use this as the base to loop through files in a directory.

The code to check whether a file is a directory or not is shown below.



So in the file above we create a class called Directorycheck.

We then put in our main() method.

In the main method, we create a file object, f, and pass the parameter named "Documents" into the this File object.

So at this point in the code, the File object f has the value of Documents.

We then call the isDirectory() function through the if statement.

The function is f.isDirectory(). This function returns a boolean value of either true or false. If the file is a directory, it returns true. If the file is not a directory, it returns false. We output the appropriate message based on this boolean value.

Since we didn't specify the path in the parameter passed into the File object, the Java program looks in the current directory, the one storing this Java file, to look for the file named Documents.

If you want to specify a directory other than the current directory, then you will have to specify the complete path.

Since this differs according to what operating system you are using, this is the only part of Java that becomes platform dependent.

In a Windows computer, you normally specify the drive you are using with a letter such as the C drive and then specify the path from there to the file that you want to check to see if it is a directory.

So if you have a file you want to check to see if it is a directory in the C:\Users\ directory, then you would write this into the string as "C:\\Users\\"

This is because "\" is an escape character; it's used for escaping strings. To show "\" in a string, you would have to put double forward slashes "\\".



And this is all that is required to check to see whether a file in a certain directory is a directory or not.


Related Resources

How to Check if a File Exists Using Java

How to Check if an Object is a File Using Java

How to Create a New File Using Java

How to Rename a File Using Java

How to Delete a File Using Java

How to Create a New Directory Using Java

How to List All Files in a Directory Using Java

How to Read a File Using Java

How to Write Data to a File Using Java

How to Get the Size of a File Using Java




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