Java - 删除文件

This quick article illustrates how to delete a File in Java – first using JDK 6, then JDK 7 and finally the Apache Commons IO library.

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

1. With Java – JDK 6

Let’s start with the standard Java 6 solution:

@Test
public void givenUsingJDK6_whenDeletingAFile_thenCorrect() throws IOException {
    new File("src/test/resources/fileToDelete_jdk6.txt").createNewFile();

    File fileToDelete = new File("src/test/resources/fileToDelete_jdk6.txt");
    boolean success = fileToDelete.delete();

    assertTrue(success);
}

As you can see – the file must exist before the delete operation; if it doesn’t, the API will not throw any exceptions but will instead return false.

2. With Java – JDK 7

Let’s move on to the JDK 7 solution:

@Test
public void givenUsingJDK7nio2_whenDeletingAFile_thenCorrect() throws IOException {
    Files.createFile(Paths.get("src/test/resources/fileToDelete_jdk7.txt"));

    Path fileToDeletePath = Paths.get("src/test/resources/fileToDelete_jdk7.txt");
    Files.delete(fileToDeletePath);
}

Now – this will make better use of exceptions. If the file doesn’t exist when the delete operation is triggered – an NoSuchFileException will be thrown by the API:

java.nio.file.NoSuchFileException: srctestresourcesfileToDelete_jdk7.txt
    at s.n.f.WindowsException.translateToIOException(WindowsException.java:79)

3. With Commons IO

Commons IO allows us to control the exceptions behavior when deleting a File. For a quiet delete that swallows any possible exceptions:

@Test
public void givenUsingCommonsIo_whenDeletingAFileV1_thenCorrect() throws IOException {
    FileUtils.touch(new File("src/test/resources/fileToDelete_commonsIo.txt"));
    File fileToDelete = FileUtils.getFile("src/test/resources/fileToDelete_commonsIo.txt");
    boolean success = FileUtils.deleteQuietly(fileToDelete);

    assertTrue(success);
}

Note that we can still determine if the operation was successful or not by simply checking the return value of the delete method.

Now – if we do want an exception to be thrown:

@Test
public void givenUsingCommonsIo_whenDeletingAFileV2_thenCorrect() throws IOException {
    FileUtils.touch(new File("src/test/resources/fileToDelete.txt"));

    FileUtils.forceDelete(FileUtils.getFile("src/test/resources/fileToDelete.txt"));
}

If the file to be deleted doesn’t exist on the filesystem, the API will throw a standard FileNotFoundException:

java.io.FileNotFoundException: File does not exist: srctestresourcesfileToDelete.txt
    at org.apache.commons.io.FileUtils.forceDelete(FileUtils.java:2275)

And there you have it – 4 simple ways to delete a File in Java.