Java – Create a File – Java – 创建一个文件

最后修改: 2014年 6月 28日


1. Overview


In this quick tutorial, we’re going to learn how to create a new File in Java – first using the Files and Path classes from NIO, then the Java File and FileOutputStream classes, Google Guava, and finally the Apache Commons IO library.

在这个快速教程中,我们将学习如何在Java中创建一个新的文件–首先使用NIO的FilesPath类,然后是Java FileFileOutputStream类,Google Guava,最后是Apache Commons IO库。

This article is part of the “Java – Back to Basic” series here on Baeldung.

本文是Baeldung网站上“Java – Back to Basic “系列的一部分。

2. Setup


In the examples, we’ll define a constant for the file name:


private final String FILE_NAME = "src/test/resources/fileToCreate.txt";

And we’ll also add a clean-up step to make sure that the file doesn’t already exist before each test, and to delete it after each test runs:


public void cleanUpFiles() {
    File targetFile = new File(FILE_NAME);

3. Using NIO Files.createFile()

3.使用NIO Files.createFile()

Let’s start by using the Files.createFile() method from the Java NIO package:

让我们从使用Java NIO包中的Files.createFile()方法开始。

public void givenUsingNio_whenCreatingFile_thenCorrect() throws IOException {
    Path newFilePath = Paths.get(FILE_NAME);

As you can see the code is still very simple; we’re now using the new Path interface instead of the old File.


One thing to note here is that the new API makes good use of exceptions. If the file already exists, we no longer have to check a return code. Instead, we’ll get a FileAlreadyExistsException:


java.nio.file.FileAlreadyExistsException: <code class="language-java">src/test/resources/fileToCreate.txt at sun.n.f.WindowsException.translateToIOException(

4. Using File.createNewFile()


Let’s now look at how we can do the same using the class:


public void givenUsingFile_whenCreatingFile_thenCorrect() throws IOException {
    File newFile = new File(FILE_NAME);
    boolean success = newFile.createNewFile();

Note that the file must not exist for this operation to succeed. If the file does exist, then the createNewFile() operation will return false.


5. Using FileOutputStream


Another way to create a new file is to use the


public void givenUsingFileOutputStream_whenCreatingFile_thenCorrect() throws IOException {
    try(FileOutputStream fileOutputStream = new FileOutputStream(FILE_NAME)){

In this case, a new file is created when we instantiate the FileOutputStream object. If a file with a given name already exists, it will be overwritten. If, however, the existing file is a directory or a new file cannot be created for any reason, then we’ll get a FileNotFoundException.


Additionally, note we used a try-with-resources statement – to be sure that a stream is properly closed.


6. Using Guava


The Guava solution for creating a new file is a quick one-liner as well:


public void givenUsingGuava_whenCreatingFile_thenCorrect() throws IOException { File(FILE_NAME));

7. Using Apache Commons IO

7.使用Apache Commons IO

The Apache Commons library provides the FileUtils.touch() method which implements the same behavior as the “touch” utility in Linux.

Apache Commons库提供了FileUtils.touch()方法,实现了与Linux中”touch“工具相同的行为。

Therefore it creates a new empty file or even a file and the full path to it in a file system:


public void givenUsingCommonsIo_whenCreatingFile_thenCorrect() throws IOException {
    FileUtils.touch(new File(FILE_NAME));

Note that this behaves slightly differently than the previous examples: if the file already exists, the operation doesn’t fail, it simply doesn’t do anything.


And there we have it – 4 quick ways to create a new file in Java.


8. Conclusion


In this article, we looked at different solutions for creating a file in Java. We used classes that are part of the JDK and external libraries.


The code for the examples is available over on GitHub.