说明：
如果我只使用AFNetworking来做这个请求……就像魅​​力一样……这就是我的AFNetworking代码：

AFHTTPClient *client = [AFHTTPClient alloc] initWithBaseURL:
                                               [NSURL URLWithString:kApiBaseUrl]];
singleton.parameterEncoding = AFJSONParameterEncoding;
[singleton setDefaultHeader:@"Accept" value:@"text/html"];
[client getPath:getPath parameters:nil success:successCallback failure:failureCallback];

如果我使用完全相同的客户端并将其附加到

MyClient *client = [MyClient getSingleton];  //MyClient is instantiated as above        
self.objectManager = [[RKObjectManager alloc] initWithHTTPClient:client];
self.objectManager.managedObjectStore = self.managedObjectStore;
// this should have already been done by my client,but putting
// it here just to be sure
[self.objectManager setAcceptHeaderWithMIMEType:@"text/html"];

[[RKObjectManager sharedManager] getObjectsAtPath:kGradesPath 
                                       parameters:nil 
                                          success:^(RKObjectRequestOperation *operation,RKMappingResult *mappingResult) {
 // handle success
} failure:^(RKObjectRequestOperation *operation,NSError *error) {
 // handle failure
}];

我得到的错误是：

restkit.network:RKObjectRequestOperation.m:576 Object request Failed: 
 Underlying HTTP request operation Failed with error: Error
 Domain=org.restkit.RestKit.ErrorDomain Code=-1016 "Expected content type {(
    "application/x-www-form-urlencoded","application/json"
)},got text/html" UserInfo=0x8f7acd0

挖掘主题..我在managedObjectRequestOperationWithRequest中设置了一个断点,然后我检查了创建的HTTPRequestOperation的acceptableContentTypes,它没有！所以我假设RestKit只是放置自己的默认可接受的内容类型..我只是不知道在哪里以及如何防止它.想法？

附：我无法控制服务器,因此我无法将其内容类型标头更改为application / JSON

更新：

事实证明,在RKObjectRequestOperation.m它从[RKMIMETypeSerialization registeredMIMETypes]获取mime类型;(第354行)..所以在RKMIMETypeSerialization.h中有方法：

/**
 Registers the given serialization class to handle content for the given MIME Type identifier.

 MIME Types may be given as either a string or as a regular expression that matches the MIME Types for which the given serialization should handle. Serializations are searched in the reverse order of their registration. If a registration is made for an already registered MIME Type,the new registration will take precedence.

 @param serializationClass The class conforming to the RKSerialization protocol to be registered as handling the given MIME Type.
 @param MIMETypeStringOrRegularExpression A string or regular expression specifying the MIME Type(s) that given serialization implementation is to be registered as handling.
 */
+ (void)registerClass:(Class<RKSerialization>)serializationClass forMIMEType:(id)MIMETypeStringOrRegularExpression;

如何使用它来注册text / html内容类型？