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java实现递归文件列表的方法

2019年07月22日 | 移动技术网IT编程 | 我要评论

本文实例讲述了java实现递归文件列表的方法。分享给大家供大家参考。具体如下：

filelisting.java如下：

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);
  }
 }
}

希望本文所述对大家的java程序设计有所帮助。