//过滤空格
NSString * urlStr = @"  A as    dd  dmm ";
NSLog(@"urlStr = %@",urlStr);

//过滤字符串前后的空格
urlStr = [urlStr stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
NSLog(@"urlStr = %@",urlStr);

//过滤中间空格
urlStr = [urlStr stringByReplacingOccurrencesOfString:@" " withString:@""];
NSLog(@"urlStr = %@",urlStr);