如何通过NSJSONSerialization在JSON中包含空值? [英] How to include null value in the JSON via NSJSONSerialization?
问题描述
我想我知道如何使用NSJSONSerialization。我正在进行的调用是:
I think I get it how to use the NSJSONSerialization over all. The call I am making is:
[NSJSONSerialization dataWithJSONObject:parameters options:0 error:&error]
其中 parameters 是一个NSDictionary,其中包含要在JSON请求中使用的键和值。一切都很好,直到我必须使用 null 作为值而不是空字符串。我找不到将值设置为 null 的方法。我需要创建的 json 示例是:
where parameters is a NSDictionary which includes keys and values to use in the JSON request. Everything is fine and all, until I have to use null as a value instead of an empty string. I can't find a way to set the value as null at all. The example of json that I need to create is:
{"target"
{"firstname":<firstname>,
"lastname":<lastname>},
"error":null
}
服务器的设置方式是,如果没有错误,它可能会出现错误,或者 null 。
The way server is setup is that it's expecting either an error as a string or a null if there's no error.
任何想法?我错过了API调用或类似的东西吗?
Any ideas? Am I missing an API call or something like that?
谢谢!
推荐答案
您必须使用 NSNull
。例如
Swift
let dict = ["firstKeyHasValue": 2342, "secondKeyHasNoValue": NSNull()]
目标-C
NSDictionary *dict = @{ @"error": [NSNull null] };
来自NSDictionary :
密钥和值都不能为零;如果你需要在字典中表示空值,你应该使用NSNull。
Neither a key nor a value can be nil; if you need to represent a null value in a dictionary, you should use NSNull.
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