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How to search for a subdirectory from a parent directory? [closed]
2 answers
import java.io.File;
import java.io.FileFilter;
import java.io.IOException;
public class DirectoryContents {
public static void main(String[] args) throws IOException {
File f = new File(".");
FileFilter directoryFilter = new FileFilter() {
public boolean accept(File file) {
return file.isDirectory();
}
};
File[] files = f.listFiles(directoryFilter);
for (File file : files) {
if (file.isDirectory())
System.out.print("directory:");
else
System.out.print(" file:");
System.out.println(file.getCanonicalPath());
}
}
}
I m able to list all the sub directories from the parent directory.
But I would like to search for particular sub directory in java.Is there any way?
directory:C:\projects\workspace\testing
how to list only subdirectories (z1) and not files? (Sub directory z1 is present in various sub directories)
directory:C:\projects\workspace\testing\z1
directory:C:\projects\workspace\testing\f5\z1
directory:C:\projects\workspace\testing\f5\a\g\h\d
The Output should be directories containing z1
Java 7 made this type of thing easy with lots of flexibility. I would use a Java 7 PathMatcher with a glob pattern (or a regex pattern if the sophistication is needed) and use it in a FileVistor. Then just walk the file tree via Files.walkFileTree().
import java.io.IOException;
import java.nio.file.FileSystems;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.PathMatcher;
import java.nio.file.Paths;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.attribute.BasicFileAttributes;
public class StackOverflow20443793
{
//Our FileVisitor Implementation. We extend SimpleFileVisitor to save work
protected class Finder extends SimpleFileVisitor<Path>
{
private final PathMatcher matcher;
Finder(String pattern)
{
matcher = FileSystems.getDefault().getPathMatcher("glob:" + pattern);
}
void find(Path path)
{
Path name = path.getFileName();
if ((name != null) && matcher.matches(name))
{
processDirectory(path);
}
}
@Override
public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs) throws IOException
{
//Since we only care about directories, we only override
// the preVisitDirectory method. The super does null checks for us
super.preVisitDirectory(dir, attrs);
find(dir);
return FileVisitResult.CONTINUE;
}
}
private void findAndProcessSubDirectories(Path startingDirectory, String pattern) throws IOException
{
Finder finder = new Finder(pattern);
Files.walkFileTree(startingDirectory, finder);
}
private void processDirectory(Path dir)
{
System.out.println(dir);
}
public static void main(String... args) throws Exception
{
StackOverflow20443793 runner = new StackOverflow20443793();
//Find all directories in path named "z1"
runner.findAndProcessSubDirectories(Paths.get("P:\\tmp\\findExample"), "z1");
System.out.println("=====");
//Find all directories in path named "z*"
runner.findAndProcessSubDirectories(Paths.get("P:\\tmp\\findExample"), "z*");
System.exit(0);
}
}
Output:
C:\projects\workspace\testing\f5\a\g\h\d\z1
C:\projects\workspace\testing\f5\z1
C:\projects\workspace\testing\z1
=====
C:\projects\workspace\testing\f5\a\g\h\d\z1
C:\projects\workspace\testing\f5\z1
C:\projects\workspace\testing\z1
C:\projects\workspace\testing\z2
For more info and examples, see http://docs.oracle.com/javase/tutorial/essential/io/find.html and the JavaDocs I linked.
Two things:
- The easiest way to search through subdirectories is by recursion.
- You need to check the filename, before printing. You can do this with regular expressions using
".*z1.*
So in total something like this
private static final FileFilter directoryFilter = new FileFilter() {
public boolean accept(File file) {
return file.isDirectory();
}
};
private static void printDirectories(File dir, string pattern) {
// Print this directory if it matches the pattern
if (dir.getName().matches(pattern)) {
System.out.println(dir.getAbsolutePath());
}
// Search all sub directories
for (String string : f.listFiles(directoryFilter)) {
printDirectories(subDir);
}
}
public static void main(String[] args) {
printDirectories(new File("."), ".*z1.*");
}