在Swift中从URL解析XML

概述我是一个全新的解析,无法找到任何没有过时的教程,也没有提出更多的问题.我有一个简单的xml文件url我试图解析. xml非常简单： <xml> <record> <EmpName>A Employee</EmpName> <EmpPhone>111-222-3333</EmpPhone> <EmpEmail>a@employee.com</E 我是一个全新的解析,无法找到任何没有过时的教程,也没有提出更多的问题.我有一个简单的xml文件url我试图解析. xml非常简单：

<xml>    <record>        <Empname>A Employee</Empname>        <EmpPhone>111-222-3333</EmpPhone>        <EmpEmail>a@employee.com</EmpEmail>        <EmpAddress>12345 Fake Street</EmpAddress>        <EmpAddress1>MyTown,Mystate ZIP</EmpAddress1>    </record></xml>

并且只想将其保存为NSDictionary(标记为键和数据作为值).到目前为止,我能够成功完成的是在控制台中打印xml字符串：

let url = NSURL(string: "http://www.urlexample.com/file.xml")let task = NSURLSession.sharedSession().dataTaskWithURL(url!) {(data,response,error) in        println(Nsstring(data: data,enCoding: NSUTF8StringEnCoding))}print(task)task.resume()

我已经完成了我发现的任何在线教程,这些教程要么过时,要么过于复杂.任何帮助表示赞赏.

过程很简单：

>创建XMLParser对象,并将数据传递给它.
>指定该解析器的委托.
>启动解析.

所以,在Swift 3/4中,它看起来像：

let task = URLSession.shared.dataTask(with: url) { data,error in    guard let data = data,error == nil else {        print(error ?? "UnkNown error")        return    }    let parser = XMLParser(data: data)    parser.delegate = self    if parser.parse() {        print(self.results ?? "No results")    }}task.resume()

问题是如何实现XMLParserDelegate方法.三个关键方法是dIDStartElement(准备接收字符的地方),foundCharacters(处理解析的实际值)和dIDEndElement(保存结果的地方).

您询问了如何解析单个记录(即单个字典),但我将向您展示解析其中一系列的更一般模式,这是XML的一种常见情况.如果你不需要一个值数组(或者只是抓住第一个值),你显然可以看到如何简化这个.

// a few constants that IDentify what element names we're looking for insIDe the XML// a few constants that IDentify what element names we're looking for insIDe the XMLlet recordKey = "record"let dictionaryKeys = Set<String>(["Empname","EmpPhone","EmpEmail","EmpAddress","EmpAddress1"])// a few variables to hold the results as we parse the XMLvar results: [[String: String]]?         // the whole array of dictionarIEsvar currentDictionary: [String: String]? // the current dictionaryvar currentValue: String?                // the current value for one of the keys in the dictionary

和

extension VIEwController: XMLParserDelegate {    // initialize results structure    func parserDIDStartdocument(_ parser: XMLParser) {        results = []    }    // start element    //    // - If we're starting a "record" create the dictionary that will hold the results    // - If we're starting one of our dictionary keys,initialize `currentValue` (otherwise leave `nil`)    func parser(_ parser: XMLParser,dIDStartElement elementname: String,namespaceURI: String?,qualifIEdname qname: String?,attributes attributeDict: [String : String]) {        if elementname == recordKey {            currentDictionary = [:]        } else if dictionaryKeys.contains(elementname) {            currentValue = ""        }    }    // found characters    //    // - If this is an element we care about,append those characters.    // - If `currentValue` still `nil`,then do nothing.    func parser(_ parser: XMLParser,foundCharacters string: String) {        currentValue? += string    }    // end element    //    // - If we're at the end of the whole dictionary,then save that dictionary in our array    // - If we're at the end of an element that belongs in the dictionary,then save that value in the dictionary    func parser(_ parser: XMLParser,dIDEndElement elementname: String,qualifIEdname qname: String?) {        if elementname == recordKey {            results!.append(currentDictionary!)            currentDictionary = nil        } else if dictionaryKeys.contains(elementname) {            currentDictionary![elementname] = currentValue            currentValue = nil        }    }    // Just in case,if there's an error,report it. (We don't want to fly blind here.)    func parser(_ parser: XMLParser,parseErrorOccurred parseError: Error) {        print(parseError)        currentValue = nil        currentDictionary = nil        results = nil    }}

对于Swift 2的再现,请参阅previous revision of this answer.

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