这篇文章旨在给自己以后需要时能及时的查到，省得每次都去baidu. 

1. xml解析库-GDataXML 
参考文章：http://blog.csdn.net/tangren03/article/details/7868246 
GDataXML下载地址： 
(1)GDataXML.h/m文件 
http://code.google.com/p/gdata-objectivec-client/source/browse/trunk/Source/XMLSupport/ 
(2)DGataDefines.h GDataTargetNamespace.h 文件 
http://code.google.com/p/gdata-objectivec-client/source/browse/trunk/Source/ 

配置过程： 
(1).引入GDataXML(4个文件) 
<arc模式下>.对GDataXML.m增加非arc注释 -fno-objc-arc 
(2).添加系统库 libxml2.dylib 
(3).Head Search Path中添加 /usr/include/libxml2 
(4).Other linker flags中添加 -lxml2 
(5).xml格式 
================================== 
<?xml version="1.0" encoding="utf-8"?>  
<Users>  
    <User id="001">  
        <name>Ryan</name>  
        <age>24</age>  
    </User>  
    <User id="002">  
        <name>Tang</name>  
        <age>23</age>  
    </User>  
</Users> 
================================== 
(6).应用 
================================== 
//获取工程目录的xml文件  
    NSString *filePath = [[NSBundle mainBundle] pathForResource:@"users" ofType:@"xml"];  
    NSData *xmlData = http://www.mamicode.com/[[NSData alloc] initWithContentsOfFile:filePath];  
      
    //使用NSData对象初始化  
    GDataXMLDocument *doc = [[GDataXMLDocument alloc] initWithData:xmlData  options:0 error:nil];  
      
    //获取根节点（Users）  
    GDataXMLElement *rootElement = [doc rootElement];  
      
    //获取根节点下的节点（User）  
    NSArray *users = [rootElement elementsForName:@"User"];  
      
    for (GDataXMLElement *user in users) {  
        //User节点的id属性  
        NSString *userId = [[user attributeForName:@"id"] stringValue];  
        NSLog(@"User id is:%@",userId);  
          
        //获取name节点的值  
        GDataXMLElement *nameElement = [[user elementsForName:@"name"] objectAtIndex:0];  
        NSString *name = [nameElement stringValue];  
        NSLog(@"User name is:%@",name);  
          
        //获取age节点的值  
        GDataXMLElement *ageElement = [[user elementsForName:@"age"] objectAtIndex:0];  
        NSString *age = [ageElement stringValue];  
        NSLog(@"User age is:%@",age);  
        NSLog(@"-------------------");  
    }