import java.util.List;import java.io.File;import java.util.ArrayList;public class IteratorUtil {    private static int level=0;        public static void IteratorDir(File file){            if(file!=null){                if(file.isFile()||file.listFiles().length ==0){                    return;                }else{                    File[] files=file.listFiles();                    files=sort(files);                    for (File f : files) {                        StringBuilder sb = new StringBuilder();                        if(f.isFile()){                            sb.append(getTab(level));                            sb.append(f.getName());                        }else{                            sb.append(getTab(level));                            sb.append(f.getName());                            sb.append("\\");                        }                        System.out.println(sb.toString());                        if(f.isDirectory()){                            level++;                            IteratorDir(f);                            level--;                        }                                            }                }            }        }        private static File[] sort(File[] files){            List
     
       flist = new ArrayList
      
       ();            for (File f : files) {                if(f.isDirectory()){                    flist.add(f);                }                            }            for (File f : files) {                if(f.isFile()){                    flist.add(f);                }                            }            return flist.toArray(new File[flist.size()]);        }        private static String getTab(int level){            StringBuilder sb = new StringBuilder();            for (int i = 0; i < level; i++) {                sb.append("\t");                            }            return sb.toString();        }}