//過濾空格     NSString * urlStr = @"   A as    dd  dmm ";     NSLog(@"urlStr = %@",urlStr);          //過濾字符串前後的空格     urlStr = [urlStr stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];     NSLog(@"urlStr = %@",urlStr);          //過濾中間空格     urlStr = [urlStr stringByReplacingOccurrencesOfString:@" " withString:@""];     NSLog(@"urlStr = %@",urlStr);