JSON 文本未以数组或对象开头，并且没有设置允许片段的选项 [英] JSON text did not start with array or object and option to allow fragments not set

问题描述

我正在从服务器发送这个 json 响应，以请求我的 IOS 7 应用程序.

I'm sending this json response from server for a request to my IOS 7 app.

{
 "root": {
    "success": "1",
    "message": "Successfully retrieved data.",
    "data": {
        "records": [
            {
                "receipt_key": "xxxxxxxx",
                "receipt_id": "xxxxxxxx",
                "store_name": "xxxxxx",
                "amount": "xxxx",
                "date_purchase": "xxxxxxxx",
                "is_processed": "x",
                "created_on": "xxxxxxxx",
                "modified_on": "xxxxxxxx",
                "modified_on_millis": "xxxxxxxx",
                "user_folder": "xxxxxxxx",
                "category_id": "xxxxxxxx",
                "is_deleted": "x",
                "currency_id": "xxxxxxxx"
            }
        ]
    }
}
}

我使用以下代码将上述 json 解析为 NSDictionary 对象.

I use the following code for parsing the above json to NSDictionary object.

 NSMutableDictionary *json=[NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments error:&error];

但是我在上面的代码中遇到了这个错误.

But I'm getting this error on the above code.

Error Domain=NSCocoaErrorDomain Code=3840 "操作不能完全的.(Cocoa 错误 3840.)"(JSON 文本未以数组或允许未设置片段的对象和选项.) UserInfo=0x8a8a700{NSDebugDescription=JSON 文本没有以数组或对象开头，并且允许未设置片段的选项.}

Error Domain=NSCocoaErrorDomain Code=3840 "The operation couldn’t be completed. (Cocoa error 3840.)" (JSON text did not start with array or object and option to allow fragments not set.) UserInfo=0x8a8a700 {NSDebugDescription=JSON text did not start with array or object and option to allow fragments not set.}

推荐答案

我在从 php 页面使用提要时遇到了同样的错误.正如您遇到的那样，生成的 json 字符串通过了视觉检查，但无法序列化.我怀疑提要的某个地方有一个隐藏的字符，所以我将每个字符转换为其 unicode 十进制等价物并检查结果:

I ran into the same error when consuming a feed from a php page. Just as you encountered, the resulting json string passed a visual inspection, but would fail to serialize. My suspicion was that there was a hidden character somewhere the feed, so I converted each character to its unicode decimal equivalent and examined the results:

NSString *feedStr = [[NSString alloc] initWithData:feedData encoding:NSUTF8StringEncoding];
for(int i=0; i<[feedStr length]; ++i)
{
    unichar c = [feedStr characterAtIndex:i];
    NSLog(@"decimal char %d", c);
}

我发现在第一个字符之前和最后一个字符之后是#65279.在快速谷歌搜索后，我发现 这是什么字符?65279，其中被标识为字节顺序标记.

I found that before the first character and after the last was the character #65279. After a quick google search I found What is this char? 65279, where this was identified as a byte order mark.

就我而言，我能够通过打开和保存所有包含的 php 文件在源代码处解决此问题，使用的文本编辑器提供了使用无 BOM 的 UTF-8 编码"编码的选项.有关 php 方面的更多信息，请参阅 如何避免在php中回显65279字符?

In my case, I was able to fix this at the source by opening and saving all included php files, using a text editor that provided an option to use the "Encode in UTF-8 without BOM" encoding. For more info on the php side, see How to avoid echoing character 65279 in php?

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