In this short article, you'll learn how to create a temporary file in Java using both NIO API and the legacy I/O API.

Using Files.createTempFile() Method

In Java 7 and higher, you can use the Files.createTempFile() static method from Java NIO Java to create a temporary file. This method creates an empty file in the default temporary-file directory, using the given prefix and suffix to generate its name.

Here is an example:

try {
    // create temporary file
    Path path = Files.createTempFile("file-", ".tmp");

    // print path
    System.out.println(path.toAbsolutePath().toString());

} catch (IOException ex) {
    ex.printStackTrace();
}

The above code will create a temporary file and print its absolute path on the console. Here is how it looks like on a Linux machine:

/tmp/file-5451298069416200317.tmp

To create a temporary file in another folder, you can use pass an instance of Path as a first argument to Files.createTempFile() method as shown below:

try {
    // folder to create temporary file
    Path folder = Paths.get("dir");

    // create temporary file
    Path path = Files.createTempFile(folder, "file-", ".tmp");

    // print path
    System.out.println(path.toAbsolutePath().toString());

} catch (IOException ex) {
    ex.printStackTrace();
}

Using File.createTempFile() Method

Another way to create a temporary file in Java is by using the legacy I/O API File.createTempFile() method. It works almost similar to the above method (create a temporary file in the default temporary-file folder):

try {
    // create temporary file
    File file = File.createTempFile("file-", ".tmp");

    // print path
    System.out.println(file.getAbsolutePath());

} catch (IOException ex) {
    ex.printStackTrace();
}

You can even explicitly specify the directory path to create a temporary file in a folder of your choice:

try {
    // folder to create temporray file
    File folder = new File("dir");

    // create temporary file
    File file = File.createTempFile("file-", ".tmp", folder);

    // print path
    System.out.println(file.getAbsolutePath());

} catch (IOException ex) {
    ex.printStackTrace();
}

Further Reading

You may be interested in other Java I/O articles:

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