import java.io.File;
import java.util.ArrayList;
import java.util.Arrays;

public class FileUtilDeal {
		public static void main(String[] args) {
			//File file = new File("E:\\極草\\img\\F20150603-1638459781.jpg");
			//fileRename(file);
			String [] fileName = getFileName("E:\\極草\\img");  // img資料夾下所有的檔名陣列
	        ArrayList<String> listFileName = new ArrayList<String>(); 
	        getAllFileName("E:\\極草\\img",listFileName);
	        for(String name:listFileName)
	        {
	        	fileRename(name);
	        }
		}
		
		public static void fileRename(String fileName){
			File files = new File("E:\\極草\\img\\"+fileName);
			String filePath = files.getPath();
			System.out.println(filePath);
			if(files.exists()){
				files.renameTo(new File("E:\\極草\\img\\"+add000(fileName)+fileName));
			}
		}
		
		public static void getAllFileName(String path,ArrayList<String> fileName)
	    {
	        File file = new File(path);
	        File [] files = file.listFiles();
	        String [] names = file.list();
	        if(names != null)
	        fileName.addAll(Arrays.asList(names));
	        for(File a:files)
	        {
	            if(a.isDirectory())
	            {
	                getAllFileName(a.getAbsolutePath(),fileName);
	            }
	        }
	    }
		//
		public static String [] getFileName(String path)
	    {
	        File file = new File(path);
	        String [] fileName = file.list();
	        return fileName;
	    }
		//保證檔名的長度為30個字元
		public static String  add000(String fileName){
			String prefix=fileName.substring(fileName.lastIndexOf(".")+1);
			int dot = fileName.lastIndexOf('.'); 
            String f = fileName.substring(0, dot); 
			int _len = 30 - f.length();
			StringBuffer buf = new StringBuffer();
			for (int i = 0; i < _len; i++) {
				buf.append("0");
			}
			return buf.toString();
		}
}