发送请求时+变成空格

NSString *baseString = [str stringByAddingPercentEncodingWithAllowedCharacters:[[NSCharacterSet characterSetWithCharactersInString:@"+"] invertedSet]];

或者

NSString *baseString = (__bridge NSString *) CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault,
                                                                                         (CFStringRef) str,
                                                                                         NULL,
                                                                                         CFSTR("+"),
                                                                                         kCFStringEncodingUTF8);  

替换字符然后

request.HTTPBody = [baseString dataUsingEncoding:NSUTF8StringEncoding];