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Swift - 解析XML格式数据（分别使用GDataXML和DDXML）

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：

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

#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

#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)")
        }        
    }
}