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Editor to share with you how java uses FileVisitor to traverse files and directories, I believe most people do not know much about it, so share this article for your reference, I hope you can learn a lot after reading this article, let's go to know it!

In early versions of Java, if you needed to traverse files in a specified directory, you needed to do it recursively, which was a bit complex and inflexible. Using the walkFileTree () method in the Files tool class in Java7, you can easily traverse all the files in the directory. This method requires a Path and a FileVisitor parameter. Where Path is the path to traverse, and FileVisitor can be seen as a file accessor, it mainly provides four methods, which can be seen in the program. The four FileVisitor methods all return a FileVisitResult object, which is an enumeration class that represents some subsequent operations after the return.

FileVisitResult consists of four common operations.

1. FileVisitResult.CONTINUE continues traversing 2, FileVisitResult.TERMINATE aborts access 3, FileVisitResult.SKIP_SIBLINGS does not access files or directories of the same level 4, FileVisitResult.SKIP_SUBTREE does not access subdirectories

You can traverse the file by creating a SimpleFileVisitor object, which is the implementation class of FileVisitor, so that you can optionally override the specified method

The following program traverses the directory using FileVisitor, and simply looks for files in the specified directory.

Package com.sdjz.test1;import java.io.IOException;import java.nio.file.FileVisitResult;import java.nio.file.Files;import java.nio.file.Path;import java.nio.file.Paths;import java.nio.file.SimpleFileVisitor;import java.nio.file.attribute.BasicFileAttributes;import java.util.List Public class FileVisitorTest {public static void main (String [] args) throws IOException {/ / use FileVisitor to traverse the directory Files.walkFileTree (Paths.get ("d:", "workspace"), new SimpleFileVisitor () {/ / trigger the method @ Override public FileVisitResult preVisitDirectory (Path dir, BasicFileAttributes attrs) throws IOException {System.out.println ("accessing" + dir + "directory") before accessing the subdirectory; return FileVisitResult.CONTINUE } / / trigger the method @ Override public FileVisitResult visitFile (Path file, BasicFileAttributes attrs) throws IOException {System.out.println ("accessing" + file + "File"); if (file.endsWith ("FilesTest.java")) {System.out.println ("- found FilesTest.java, file contents -"); List list = Files.readAllLines (file); / / print out the contents of the file System.out.println (list) Return FileVisitResult.TERMINATE;} return FileVisitResult.CONTINUE;} / / trigger the method @ Override public FileVisitResult visitFileFailed (Path file, IOException exc) throws IOException {/ / write some specific business logic return super.visitFileFailed (file, exc);} / / trigger the method @ Override public FileVisitResult postVisitDirectory (Path dir, IOException exc) throws IOException {/ / write some specific business logic return super.postVisitDirectory (dir, exc) after accessing the directory });}}

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