The Java Tutorials have been written for JDK 8. Examples and practices described in this page don't take advantage of improvements introduced in later releases and might use technology no longer available.
See Java Language Changes for a summary of updated language features in Java SE 9 and subsequent releases.
See JDK Release Notes for information about new features, enhancements, and removed or deprecated options for all JDK releases.
Prior to the Java SE 7 release, the java.io.File
class was the mechanism used for file I/O, but it had several drawbacks.
rename
method didn't work consistently across platforms.File
methods didn't scale. Requesting a large directory listing over a server could result in a hang. Large directories could also cause memory resource problems, resulting in a denial of service.Perhaps you have legacy code that uses java.io.File
and would like to take advantage of the java.nio.file.Path
functionality with minimal impact to your code.
The java.io.File
class provides the
toPath
method, which converts an old style File
instance to a java.nio.file.Path
instance, as follows:
Path input = file.toPath();
You can then take advantage of the rich feature set available to the Path
class.
For example, assume you had some code that deleted a file:
file.delete();
You could modify this code to use the Files.delete
method, as follows:
Path fp = file.toPath(); Files.delete(fp);
Conversely, the
Path.toFile
method constructs a java.io.File
object for a Path
object.
Because the Java implementation of file I/O has been completely re-architected in the Java SE 7 release, you cannot swap one method for another method. If you want to use the rich functionality offered by the java.nio.file
package, your easiest solution is to use the
File.toPath
method as suggested in the previous section. However, if you do not want to use that approach or it is not sufficient for your needs, you must rewrite your file I/O code.
There is no one-to-one correspondence between the two APIs, but the following table gives you a general idea of what functionality in the java.io.File
API maps to in the java.nio.file
API and tells you where you can obtain more information.
java.io.File Functionality | java.nio.file Functionality | Tutorial Coverage |
---|---|---|
java.io.File |
java.nio.file.Path |
The Path Class |
java.io.RandomAccessFile |
The SeekableByteChannel functionality. |
Random Access Files |
File.canRead , canWrite , canExecute |
Files.isReadable , Files.isWritable , and Files.isExecutable .On UNIX file systems, the Managing Metadata (File and File Store Attributes) package is used to check the nine file permissions. |
Checking a File or Directory Managing Metadata |
File.isDirectory() , File.isFile() , and File.length() |
Files.isDirectory(Path, LinkOption...) , Files.isRegularFile(Path, LinkOption...) , and Files.size(Path) |
Managing Metadata |
File.lastModified() and File.setLastModified(long) |
Files.getLastModifiedTime(Path, LinkOption...) and Files.setLastMOdifiedTime(Path, FileTime) |
Managing Metadata |
The File methods that set various attributes: setExecutable , setReadable , setReadOnly , setWritable |
These methods are replaced by the Files method setAttribute(Path, String, Object, LinkOption...) . |
Managing Metadata |
new File(parent, "newfile") |
parent.resolve("newfile") |
Path Operations |
File.renameTo |
Files.move |
Moving a File or Directory |
File.delete |
Files.delete |
Deleting a File or Directory |
File.createNewFile |
Files.createFile |
Creating Files |
File.deleteOnExit |
Replaced by the DELETE_ON_CLOSE option specified in the createFile method. |
Creating Files |
File.createTempFile |
Files.createTempFile(Path, String, FileAttributes<?>) , Files.createTempFile(Path, String, String, FileAttributes<?>) |
Creating Files Creating and Writing a File by Using Stream I/O Reading and Writing Files by Using Channel I/O |
File.exists |
Files.exists and Files.notExists |
Verifying the Existence of a File or Directory |
File.compareTo and equals |
Path.compareTo and equals |
Comparing Two Paths |
File.getAbsolutePath and getAbsoluteFile |
Path.toAbsolutePath |
Converting a Path |
File.getCanonicalPath and getCanonicalFile |
Path.toRealPath or normalize |
Converting a Path (toRealPath )Removing Redundancies From a Path ( normalize ) |
File.toURI |
Path.toURI |
Converting a Path |
File.isHidden |
Files.isHidden |
Retrieving Information About the Path |
File.list and listFiles |
Path.newDirectoryStream |
Listing a Directory's Contents |
File.mkdir and mkdirs |
Files.createDirectory |
Creating a Directory |
File.listRoots |
FileSystem.getRootDirectories |
Listing a File System's Root Directories |
File.getTotalSpace , File.getFreeSpace , File.getUsableSpace |
FileStore.getTotalSpace , FileStore.getUnallocatedSpace , FileStore.getUsableSpace , FileStore.getTotalSpace |
File Store Attributes |