判断文件存在————判断文件的后缀名

NSFileManager *fm=[NSFileManager defaultManager];
         if ([fm fileExistsAtPath:path]) {
           
            NSDirectoryEnumerator *enumerator=[fm enumeratorAtPath:path];
            
            NSString *file;
            while (file = [enumerator nextObject]) {
              if ([[file pathExtension] isEqualToString: @"zip"]) {
                  [fm removeItemAtPath:[path stringByAppendingPathComponent:file]error:nil];