列出文件和目录

File dir = new File("directoryName");  
  String[] children = dir.list();  
  if (children == null) {  
      // Either dir does not exist or is not a directory  
  } else {  
      for (int i=0; i < children.length; i++) {  
          // Get filename of file or directory  
          String filename = children[i];  
      }  
  }  
     
  // It is also possible to filter the list of returned files.  
  // This example does not return any files that start with `.'.  
  FilenameFilter filter = new FilenameFilter() {  
      public boolean accept(File dir, String name) {  
          return !name.startsWith(".");  
      }  
  };  
  children = dir.list(filter);  
     
  // The list of files can also be retrieved as File objects  
  File[] files = dir.listFiles();  
     
  // This filter only returns directories  
  FileFilter fileFilter = new FileFilter() {  
      public boolean accept(File file) {  
          return file.isDirectory();  
      }  
  };  
  files = dir.listFiles(fileFilter);