List all in the Directory

/*
 * Created on 2005-4-8
 *
 * TODO To change the template for this generated file go to
 * Window - Preferences - Java - Code Style - Code Templates
 */
package c12;
import java.io.File;
/**
 * @author zhang
 *
 * TODO To change the template for this generated type comment go to Window -
 * Preferences - Java - Code Style - Code Templates
 */
public class ListDir {
 private StringBuffer list = new StringBuffer();
 private static boolean disp_Dir = false;
 private static void listDir(File file) {
  String[] list;
  String absolutPath;
  absolutPath = file.getAbsolutePath();
  list = file.list();
  for (int i = 0; i < list.length; i++) {
   File temp = new File(absolutPath + "/" + list[i]);
   if (temp.isDirectory()) {
    if (ListDir.disp_Dir)
     ListDir.listDir(temp);
    else
     System.out.println(temp.getAbsolutePath());
   } else {
    System.out.println(temp.getAbsolutePath());
   }
  }
 }
 private static void usage() {
  System.out.println("Usage: DirList directory.../n" + "");
 }
 public static void main(String[] args) {
  String path = null;
  if (args.length == 0) {
   usage();
   System.exit(1);
  }
  if (args.length == 1) {
   path=args[0];
  }
  if(args.length==2){
   if(args[0].equalsIgnoreCase("-d"))
   ListDir.disp_Dir=true;
   path=args[1];
  }
  try {
   File file = new File(path);
   listDir(file);
  } catch (NullPointerException npe) {
   npe.printStackTrace();
   System.out.println("错误: 文件夹不存在!!!");
  }
 }
}