- (NSString *)encodeToPercentEscapeString: (NSString *) input

{

    // Encode all the reserved characters, per RFC 3986

    // (<http://www.ietf.org/rfc/rfc3986.txt>)

    NSString *outputStr = (NSString *)

    CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault,

                                            (CFStringRef)input,

                                            NULL,

                                            (CFStringRef)@"!*'();:@&=+$,/?%#[]",

                                            kCFStringEncodingUTF8);

    return outputStr;

}

- (NSString *)decodeFromPercentEscapeString: (NSString *) input

{

    NSMutableString *outputStr = [NSMutableString stringWithString:input];

    [outputStr replaceOccurrencesOfString:@"+"

                               withString:@" "

                                  options:NSLiteralSearch

                                    range:NSMakeRange(, [outputStr length])];

    return [outputStr stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

}

 NSString *aa = [self encodeToPercentEscapeString:@"测试测试"];

    NSString *bb = [self encodeToPercentEscapeString:@"7.88"];

    NSString *postStr  =[NSString stringWithFormat:@"orderDesc=%@&orderAmt=%@",aa,bb];

    NSString  *base64Str= [GTMBase64 encodeBase64String:postStr];