ios – RestKit 0.20 JSON对象被序列化为POST主体中的GET样式请求

我得到这个(从休息工具包日志)：

request.body=title=A%20glorIoUs%20walk%20in%20the%20woods&startDateTime=2013-01-13%2016%3A09%3A33%20%2B0000&endDateTime=2013-01-13%2016%3A09%3A43%20%2B0000&points[][longitude]=-122.0307725&points[][latitude]=37.3310798&points[][longitude]=-122.0307334&points[][latitude]=37.33154242&points[][longitude]=-122.03075743&points[][latitude]=37.33138305&points[][longitude]=-122.03075659&points[][latitude]=37.33131185&points[][longitude]=-122.03057969&points[][latitude]=37.33156519&points[][longitude]=-122.03075535&points[][latitude]=37.33144466&points[][longitude]=-122.03076342&points[][latitude]=37.33123666&points[][longitude]=-122.03074488&points[][latitude]=37.33149482&points[][longitude]=-122.03068145&points[][latitude]=37.33155419&points[][longitude]=-122.03062909&points[][latitude]=37.33156564&points[][longitude]=-122.03076853&points[][latitude]=37.33115792

当我想要这个(带有大括号的普通json对象和points属性的数组)时：

{
    title: "Something",startDateTime: "dateinfo",endDateTime: "moredateinfo",points: [
        {
            latitude: "37.33131313",longitude: "122.4325454"
        },{
            latitude: "37.33131313",longitude: "122.4325454"
        }
    ]
}

我有两个主要对象：DLWalk包含一个DLPoint对象的NSSet(它们是CoreData对象,但目前我忽略了它,只关注创建HTTP请求)

这是我用来创建请求的代码：

// Point mapping
RKObjectMapping *mappingPoint = [RKObjectMapping requestMapping];
[mappingPoint addAttributeMappingsFromArray:@[@"latitude",@"longitude"]];
RKRequestDescriptor *reqDescPoint = [RKRequestDescriptor requestDescriptorWithMapping:mappingPoint objectClass:[DLPoint class] rootKeyPath:nil];

// Walk mapping
RKObjectMapping *mappingWalk = [RKObjectMapping requestMapping];
[mappingWalk addAttributeMappingsFromArray:@[@"endDateTime",@"startDateTime",@"title"]];
RKRequestDescriptor *reqDescWalk = [RKRequestDescriptor requestDescriptorWithMapping:mappingWalk objectClass:[DLWalk class] rootKeyPath:nil];


// Define the relationship mapping
[mappingWalk addPropertyMapping:[RKRelationshipMapping relationshipMappingFromKeyPath:@"points" toKeyPath:@"points" withMapping:mappingPoint]];

RKObjectManager *manager = [RKObjectManager managerWithBaseURL:[NSURL URLWithString:@"http://192.168.1.10:8080"]];
                            [manager addRequestDescriptor:reqDescWalk];
                            [manager addRequestDescriptor:reqDescPoint];
                            [manager addResponseDescriptor:responseDescriptor];

// POST to create
[manager postObject:walk path:@"/walk/save" parameters:nil success:nil failure:nil];

所以问题是：为什么我的POST主体中没有看到正常的JSON对象？