Java I/O之用FilenameFilter实现根据文件扩展名删除文件

在Java中，你可以通过实现FilenameFilter类并重写accept(File dir, String name) 方法实现文件过滤功能。

在这个例子中，我们向你展示在“c:\\folder”路径下列出所有“.txt”格式的文件并删除。

package  com.it161.demo;

import  java.io.*;

public  class  FileChecker {

   private  static  final  String FILE_DIR =  "c:\\folder" ;
   private  static  final  String FILE_TEXT_EXT =  ".txt" ;

   public  static  void  main(String args[]) {
    new  FileChecker().deleteFile(FILE_DIR,FILE_TEXT_EXT);
   }

   public  void  deleteFile(String folder, String ext){

     GenericExtFilter filter =  new  GenericExtFilter(ext);
     File dir =  new  File(folder);

     //list out all the file name with .txt extension
     String[] list = dir.list(filter);

     if  (list.length ==  0 )  return ;

     File fileDelete;

     for  (String file : list){
     String temp =  new  StringBuffer(FILE_DIR)
                      .append(File.separator)
                      .append(file).toString();
        fileDelete =  new  File(temp);
        boolean  isdeleted = fileDelete.delete();
        System.out.println( "file : "  + temp +  " is deleted : "  + isdeleted);
     }
   }

   //inner class, generic extension filter
   public  class  GenericExtFilter  implements  FilenameFilter {

       private  String ext;

       public  GenericExtFilter(String ext) {
         this .ext = ext;
       }

       public  boolean  accept(File dir, String name) {
         return  (name.endsWith(ext));
       }
    }
}