iphone – 在目标C中创建一个json字符串

我必须动态生成一个json字符串,并需要发送到服务器.有没有人知道如何使用NS JSONserialization来做到这一点.下面是我的字符串

{
    "surveyid": "Survey1","responsetime": "dd/mm/yyyy hh:mm:ss","LOCATIOn": null,"surveyresponses": [
        {
            "questionid": "111","responses": [
                {
                    "response": "Good","optionid": 1,"language": "en"
                }
            ]
        },{
            "questionid": "112","responses": [
                {
                    "response": "bad","optionid": 2,"language": "en"
                }
            ]
        }

    ]
}

如何创建一个@R_197_10495@ng.json,如果有人知道请帮助.提前致谢.

NSMutableDictionary *Dict = [[NSMutableDictionary alloc]init];
[Dict SETVALue:@"Survey1" forKey:@"surveyid"];
[Dict SETVALue:@"responsetime" forKey:@"dd/mm/yyyy hh:mm:ss"];
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.
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