Iphone RestKit 0.2x：如何在应用映射之前检查键路径的存在

在我的应用程序中，我执行以下操作：

[itineraryMapping addPropertyMapping:[RKRelationshipMapping relationshipMappingFromKeyPath:@"inboundInfo" toKeyPath:@"inboundInfo" withMapping:flightInfoMapping]];

//configuring the dynamic mapping
[dynamicMapping setObjectMappingForRepresentationBlock:^RKEntityMapping *(id representation) {

    if([[representation objectForKey:@"inboundInfo"] isKindOfClass:[NSDictionary class]]) {
        if(![itineraryMapping.propertyMappings containsObject:inboundInfoMapping]) { //to prevent adding inboundInfoMapping more than once
            [itineraryMapping addPropertyMapping:inboundInfoMapping];
        }
    }

    //if inboundInfo is not a dictionary simply return the itineraryMapping without adding inboundInfoMapping on it
    return itineraryMapping;

}];

但是键

inboundInfo

可能会返回，也可能不会返回

JSON

，根据一些标准，我不想为

objectManager

添加一个全新的（大的）响应描述符来满足这种情况，在添加属性映射之前，是否有方法检查

inboundInfo

键路径是否存在

p、 如果

inboundInfo

没有带

JSON

返回，那么上面的代码行将导致崩溃，删除应用程序中的代码行就可以了

编辑：使用

RKDynamicMapping

解决，如下所示：

[itineraryMapping addPropertyMapping:[RKRelationshipMapping relationshipMappingFromKeyPath:@"inboundInfo" toKeyPath:@"inboundInfo" withMapping:flightInfoMapping]];

//configuring the dynamic mapping
[dynamicMapping setObjectMappingForRepresentationBlock:^RKEntityMapping *(id representation) {

    if([[representation objectForKey:@"inboundInfo"] isKindOfClass:[NSDictionary class]]) {
        if(![itineraryMapping.propertyMappings containsObject:inboundInfoMapping]) { //to prevent adding inboundInfoMapping more than once
            [itineraryMapping addPropertyMapping:inboundInfoMapping];
        }
    }

    //if inboundInfo is not a dictionary simply return the itineraryMapping without adding inboundInfoMapping on it
    return itineraryMapping;

}];

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您可以使用

RKDynamicMapping

运行一个代码块，该代码块分析响应并决定要应用哪个映射

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（动态对象映射部分）

方法setObjectMapping:whenValueOfKeyPath:isEqualTo在文档中已过时，因为它在0.2x中不存在。。。