json - Cocoa - 解析 JSON 字符串

Question

我知道网络上充满了这方面的示例，但我已经尝试了所有方法，但我遗漏了一些东西。我想将 JSON 字符串解析为字典。

E 有服务器的响应:

{"type":"response", "action":"mkac", "result":"[{"Band":"Adele","Hits":422},{"Band":"Bryan Adams","Hits":93},{"Band":"Adai","Hits":30},{"Band":"Adamo","Hits":18},{"Band":"Adelle","Hits":15}]"}

我做:

NSError *parseError = nil;
                        NSDictionary *outputDictionary = 
                        [NSJSONSerialization JSONObjectWithData: [output dataUsingEncoding:NSUTF8StringEncoding]
                                                        options: NSJSONReadingMutableContainers
                                                          error: &parseError];
                        NSLog(@"server said: %@", [outputDictionary objectForKey:@"result"]);

但是outputDictionary总是给我null。

有人可以帮我吗？

非常感谢。

Answer 1

是的，您的 json 格式错误。如果您正确设置格式，您就会明白原因:

{
  "type":"response", 
  "action":"mkac", 
  "result":"[{"Band":"Adele","Hits":422},{"Band":"Bryan Adams","Hits":93},{"Band":"Adai","Hits":30},{"Band":"Adamo","Hits":18},{"Band":"Adelle","Hits":15}]"
}

您会注意到 "result" 的值以 " 字符开头，这意味着该值在技术上是 "[{"。但是在那之后，它遇到了 Band。由于 Band 没有用双引号引起来(或者前面有 , 或} 等)，它会产生解析错误。如果删除 [{ 之前和 }] 之后的双引号，那么它正确解析:

{
  "type":"response", 
  "action":"mkac", 
  "result":[
    {
      "Band":"Adele",
      "Hits":422
    },
    {
      "Band":"Bryan Adams",
      "Hits":93
    },
    {
      "Band":"Adai",
      "Hits":30
    },
    {
      "Band":"Adamo",
      "Hits":18
    },
    {
      "Band":"Adelle",
      "Hits":15
    }
  ]
}