Swift-解析XML格式数据（分别使用GDataXML和DDXML）

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在做一些应用的时候经常需要用到XML解析，比如获取Web Service数据，读取RSS新闻或者博客数据源。下面演示了两个非常方便高效的XML库在Swift里的调用方法。

假设需要被解析的XML数据文件users.xml如下：

<?xml version="1.0" encoding="utf-8"?>  

<Users>  

    <User id="101">

        <name>航歌</name>

        <tel>

            <mobile>1234567</mobile>

            <home>025-8100000</home>

        </tel>  

    </User>  

    <User id="102">

        <name>hangge</name>

        <tel>

            <mobile>8989889</mobile>

            <home>025-8122222</home>

        </tel> 

    </User>  

</Users>

我们需要实现的功能是解析并打印出需要的数据：

1 2	`User: uid:101,uname:航歌,mobile:1234567,home:025-8100000` `User: uid:102,uname:hangge,mobile:8989889,home:025-8122222`

一，使用GDataXML（这个是google出品的）

1，在build phases -> Link Binary With Libraries中，点击“+”添加“libxml2.2.dylib”

2，在build setting -> Header Search Paths里添加 ${SDK_DIR}/usr/include/libxml2

3，在build setting里的Objective-C编译选项里，把自动引用计数改为No，否则在应用GDataXML库时会编译有错

4，添加bridge.h头文件并设置到编译参数里

1	`#import` `"GDataXMLNode.h"`

5，导入GDataXML库文件（GDataXMLNode.h和GDataXMLNode.m），代码结构如下：

6，开始解析（ViewController.swift）

import UIKit
 
class ViewController: UIViewController {

    override func viewDidLoad() {

        super.viewDidLoad()

        // Do any additional setup after loading the view, typically from a nib.

        var label:UILabel = UILabel(frame:CGRectMake(100, 100,300,100));

        label.text = "输出结果在控制台"

        self.view.addSubview(label)

        //测试Swift调用Object的XML库功能

        testXML()

    }

    override func didReceiveMemoryWarning() {

        super.didReceiveMemoryWarning()

        // Dispose of any resources that can be recreated.

    }
 
    func testXML() {

        //获取xml文件路径

        var path = NSBundle.mainBundle().pathForResource("users", ofType:"xml")

        //获取xml文件内容

        var xmlData = NSData(contentsOfFile:path!)

        //可以转换为字符串输出查看

        //println(NSString(data:xmlData, encoding:NSUTF8StringEncoding))

        //使用NSData对象初始化文档对象

        //这里的语法已经把OC的初始化函数直接转换过来了

        var doc:GDataXMLDocument = GDataXMLDocument(data:xmlData, options : 0, error : nil)

        //获取Users节点下的所有User节点，显式转换为element类型编译器就不会警告了

        //var users = doc.rootElement().elementsForName("User") as GDataXMLElement[]

        //通过XPath方式获取Users节点下的所有User节点，在路径复杂时特别方便

        var users = doc.nodesForXPath("//User", error:nil) as [GDataXMLElement]

        for user in users {

            //User节点的id属性

            let uid = user.attributeForName("id").stringValue()

            //获取name节点元素

            let nameElement = user.elementsForName("name")[0] as GDataXMLElement

            //获取元素的值

            let uname =  nameElement.stringValue()

            //获取tel子节点

            let telElement = user.elementsForName("tel")[0] as GDataXMLElement

            //获取tel节点下mobile和home节点

            let mobile = (telElement.elementsForName("mobile")[0] as GDataXMLElement).stringValue()

            let home = (telElement.elementsForName("home")[0] as GDataXMLElement).stringValue()

            //输出调试信息

            println("User: uid:\(uid),uname:\(uname),mobile:\(mobile),home:\(home)")

        }       

    }
}

示例下载：GDataXML.zip

二，使用DDXML

1，2，3步同上

4，添加bridge.h头文件并设置到编译参数里

1 2	`#import` `"DDXML.h"` `#import` `"DDXMLElementAdditions.h"`

5，导入DDXML库文件

6，开始解析（ViewController.swift）

import UIKit
 
class ViewController: UIViewController {

    override func viewDidLoad() {

        super.viewDidLoad()

        // Do any additional setup after loading the view, typically from a nib.

        var label:UILabel = UILabel(frame:CGRectMake(100, 100,300,100));

        label.text = "输出结果在控制台"

        self.view.addSubview(label)

        //测试Swift调用Object的XML库功能

        testXML()

    }

    override func didReceiveMemoryWarning() {

        super.didReceiveMemoryWarning()

        // Dispose of any resources that can be recreated.

    }

    func testXML() {

        //获取xml文件路径

        var path = NSBundle.mainBundle().pathForResource("users", ofType:"xml")

        //获取xml文件内容

        var xmlData = NSData(contentsOfFile:path!)

        //构造XML文档

        var doc = DDXMLDocument(data: xmlData, options:0, error:nil)

        //利用XPath来定位节点（XPath是XML语言中的定位语法，类似于数据库中的SQL功能）

        var users = doc.nodesForXPath("//User", error:nil) as [DDXMLElement]

        for user in users {

            let uid = user.attributeForName("id").stringValue()

            //DDXMLElementAdditions提供了elementForName获取单个节点，不用获取数组了

            let uname = user.elementForName("name").stringValue()

            //获取tel节点的子节点

            let telElement = user.elementForName("tel") as DDXMLElement

            let mobile = (telElement.elementForName("mobile") as DDXMLElement).stringValue()

            let home = (telElement.elementForName("home") as DDXMLElement).stringValue()

            println("User: uid:\(uid),uname:\(uname),mobile:\(mobile),home:\(home)")

        }        

    }
}