NSJSONSerialization 中未转义的控制字符答案

【问题标题】：Unescaped control characters in NSJSONSerializationNSJSONSerialization 中未转义的控制字符
【发布时间】：2012-06-26 00:27:59
【问题描述】：

我有需要解析的 JSON http://www.progmic.com/ielts/retrive.php。当我使用 NSJSONSerialization 执行此操作时，出现“字符 1981 周围未转义的控制字符”错误。

我需要知道：

什么是未转义的控制字符？有清单之类的吗？
如何消除此错误？最简单的方法？

提前致谢。

【问题讨论】：

标签： objective-c escaping nsjsonserialization

【解决方案1】：

我添加了这个方法来从检索到的字符串中删除未转义的字符：

- (NSString *)stringByRemovingControlCharacters: (NSString *)inputString 
{ 
    NSCharacterSet *controlChars = [NSCharacterSet controlCharacterSet]; 
    NSRange range = [inputString rangeOfCharacterFromSet:controlChars]; 
    if (range.location != NSNotFound) { 
        NSMutableString *mutable = [NSMutableString stringWithString:inputString]; 
        while (range.location != NSNotFound) { 
            [mutable deleteCharactersInRange:range]; 
            range = [mutable rangeOfCharacterFromSet:controlChars]; 
        } 
        return mutable; 
    } 
    return inputString; 
}

收到NSData后，我将其转换为NSString，调用上面的方法得到一个去掉了控制字符的新字符串，然后再将新的NSString转换为NSData做进一步的处理。

【讨论】：

在使用您的方法后，iOS 7 出现此错误：Error Domain=NSCocoaErrorDomain Code=3840 “无法完成操作。（Cocoa 错误 3840。）”（周围的对象形状错误字符 12171.) UserInfo=0x10a30b020 {NSDebugDescription=字符 12171 周围的对象格式错误。}
您先生，刚刚救了我的命！谢谢

【解决方案2】：

在使用 NSJSONSerialization 之前你在做什么？检查编码，也许问题出在那儿。

我很快尝试了，它奏效了。源 JSON 有效。这是我使用漂亮的打印物将数组序列化回 JSON 时得到的结果：

[
  {
    "url2": "http://ielts.progmic.com/app/i_COFANewSouthWhales.html",
    "title": "COFA New South Whales ",
    "img": "http://ielts.progmic.com/images/uni/1340407904.jpg",
    "url": "http://ielts.progmic.com/app/COFANewSouthWhales.html",
    "desc": "The College offers nine undergraduate degrees including some double degrees associated with other UNSW faculties.",
    "img2": "http://ielts.progmic.com/images/uni/thumb/1340407904.jpg"
  },
  {
    "url2": "http://ielts.progmic.com/app/i_RoyalCollegeOfArts.html",
    "title": "Royal College Of Arts ",
    "img": "http://ielts.progmic.com/images/uni/1340542224.jpg",
    "url": "http://ielts.progmic.com/app/RoyalCollegeOfArts.html",
    "desc": "The Royal College of Art (informally the RCA) is a public research university specialised in art and design located in London, United Kingdom. It is the world's only wholly postgraduate university of art and design, offering the degrees of Master of Arts (M.A.), Master of Philosophy (M.Phil.) and Doctor of Philosophy (Ph.D.). It was founded in 1837",
    "img2": "http://ielts.progmic.com/images/uni/thumb/1340542224.jpg"
  },
  {
    "url2": "http://ielts.progmic.com/app/i_MIDDLESEXUNIVERSITY.html",
    "title": "MIDDLESEX UNIVERSITY ",
    "img": "http://ielts.progmic.com/images/uni/1340410005.jpg",
    "url": "http://ielts.progmic.com/app/MIDDLESEXUNIVERSITY.html",
    "desc": "We have a reputation for the highest quality teaching, research that makes a real difference to people’s lives and a practical, innovative approach to working with businesses to develop staff potential and provide solutions to business issues. Our expertise is wide ranging, from engineering, information, health and social sciences, to business, arts and education - and we’re national leaders in work based learning solutions.",
    "img2": "http://ielts.progmic.com/images/uni/thumb/1340410005.jpg"
  },
  {
    "url2": "http://ielts.progmic.com/app/i_UNIVERSITYOFSCOTLAND.html",
    "title": "UNIVERSITY OF SCOTLAND ",
    "img": "http://ielts.progmic.com/images/uni/1340410189.jpg",
    "url": "http://ielts.progmic.com/app/UNIVERSITYOFSCOTLAND.html",
    "desc": " Founded in 1451, Glasgow is the fourth-oldest university in the English-speaking world. Over the last five centuries and more, we’ve constantly worked to push the boundaries of what’s possible. We’ve fostered the talents of seven Nobel laureates, one Prime Minister and Scotland’s inaugural First Minister. We’ve welcomed Albert Einstein to give a lecture on the origins of the general theory of relativity. Scotland’s first female graduates completed their degrees here in 1894 and the world’s first ultrasound images of a foetus were published by Glasgow Professor Ian Donald in 1958. In 1840 we became the first university in the UK to appoint a Professor of Engineering, and in 1957, the first in Scotland to have an electronic computer. All of this means that if you choose to work or study here, you’ll be walking in the footsteps of some of the world’s most renowned innovators, from scientist Lord Kelvin and economist Adam Smith, to the pioneer of television John Logie Baird.",
    "img2": "http://ielts.progmic.com/images/uni/thumb/1340410189.jpg"
  }
]

您可以将 JSON 复制并粘贴到一个文件中，以各种编码保存它，然后查看您的代码发生了什么。 UTF-8 应该是要走的路。

【讨论】：