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本文實例講述了java完成遞歸文件列表的辦法。分享給年夜家供年夜家參考。詳細以下:
FileListing.java以下:
import java.util.*;
import java.io.*;
/**
* Recursive file listing under a specified directory.
*
* @author javapractices.com
* @author Alex Wong
* @author anonymous user
*/
public final class FileListing {
/**
* Demonstrate use.
*
* @param aArgs - <tt>aArgs[0]</tt> is the full name of an existing
* directory that can be read.
*/
public static void main(String... aArgs) throws FileNotFoundException {
File startingDirectory= new File(aArgs[0]);
List<File> files = FileListing.getFileListing(startingDirectory);
//print out all file names, in the the order of File.compareTo()
for(File file : files ){
System.out.println(file);
}
}
/**
* Recursively walk a directory tree and return a List of all
* Files found; the List is sorted using File.compareTo().
*
* @param aStartingDir is a valid directory, which can be read.
*/
static public List<File> getFileListing(
File aStartingDir
) throws FileNotFoundException {
validateDirectory(aStartingDir);
List<File> result = getFileListingNoSort(aStartingDir);
Collections.sort(result);
return result;
}
// PRIVATE //
static private List<File> getFileListingNoSort(
File aStartingDir
) throws FileNotFoundException {
List<File> result = new ArrayList<File>();
File[] filesAndDirs = aStartingDir.listFiles();
List<File> filesDirs = Arrays.asList(filesAndDirs);
for(File file : filesDirs) {
result.add(file); //always add, even if directory
if ( ! file.isFile() ) {
//must be a directory
//recursive call!
List<File> deeperList = getFileListingNoSort(file);
result.addAll(deeperList);
}
}
return result;
}
/**
* Directory is valid if it exists, does not represent a file, and can be read.
*/
static private void validateDirectory (
File aDirectory
) throws FileNotFoundException {
if (aDirectory == null) {
throw new IllegalArgumentException("Directory should not be null.");
}
if (!aDirectory.exists()) {
throw new FileNotFoundException("Directory does not exist: " + aDirectory);
}
if (!aDirectory.isDirectory()) {
throw new IllegalArgumentException("Is not a directory: " + aDirectory);
}
if (!aDirectory.canRead()) {
throw new IllegalArgumentException("Directory cannot be read: " + aDirectory);
}
}
}
願望本文所述對年夜家的java法式設計有所贊助。