Javaはフォルダーの内容を削除します

  public static boolean forbidFormat(String threeLetter){
        List<String> fileFormat = new ArrayList<String>();
        fileFormat.add("pdf"); //删除什么文件可多个
        if(fileFormat.contains(threeLetter)){
            return true;
        }else{
            return false;
        }
    }

   File file = new File("E:/upload/protocol/");
            boolean isDirectory = file.isDirectory();
            if (isDirectory) {
                String[] files = file.list();
                for (String path : files) {

                    String afterPointLetter = path.substring(path.lastIndexOf(".") + 1, path.length());
                    if (forbidFormat(afterPointLetter)) {
                        System.out.println(DOWN_ADDRESS + path);
                        File deleteFile = new File(DOWN_ADDRESS + path);
                        if (deleteFile.exists()) {
                            deleteFile.delete();
                        }
                    }
                }
                log.info("---------删除成功");


            } else {
                if (file.isFile()) {
                    file.delete();
                }
            }