到ios6的时候之前在ios5中用的库文件libxml2.2.7.7不能用了，要改成libxml2或者libxml2.2。我不知道要怎么改，可能下边这个设置就是改法了。
使用XPath解析html
可以从此处 https://github.com/topfunky/hpple下载工程，将TFHpple.h,TFHpple.m,TFHppleElement.h,TFHppleElement.m,XPathQuery.h,XPathQuery.m加到自己的项目中，在Frameworks中导入libxml2.x
在项目中找到Other Linker Flags，加入-libxml2
在项目中找到Header Search Paths，加入/usr/include/libxml2
代码如下：
NSString *urlString = nil;
urlString = @"http://www.xiyou.edu.cn/new/lm.jsp?urltype=tree.TreeTempUrl&wbtreeid=724";
NSData *htmlData = [[NSData alloc] initWithContentsOfURL:[NSURL URLWithString:urlString]];
NSData *toHtmlData = [self toUTF8:htmlData];
TFHpple *xpathParser = [[TFHpple alloc] initWithHTMLData:toHtmlData];
NSArray *aArray = [xpathParser searchWithXPathQuery:@"//a"];
if ([span count] > 0) {
for (int i = 87; i < 102; i++) {
TFHppleElement *aElement = [aArray objectAtIndex:i];
NSArray *aArr = [aElement children];
TFHppleElement *aEle = [aArr objectAtIndex:0];
NSArray *aChild = [aEle children];
TFHppleElement *aChildEle = [aChild objectAtIndex:0];
NSArray *aChildren = [aChildEle children];
NSString *aStr = [[aChildren objectAtIndex:0] content];
NSLog(@"aStr:%@",aStr);
NSDictionary *aAttributeDict = [aElement attributes];
NSLog(@"aAttributeDict:%@",aAttributeDict);
//获取a中的属性值
NSString *hrefStr = [NSString stringWithFormat:@"http://www.xiyou.edu.cn%@",[aAttributeDict objectForKey:@"href"]];
NSLog(@"hrefStr:%@",hrefStr);
[currentNewsArr addObject:aStr];
[currentHrefArr addObject:hrefStr];
[htmlData release];
[xpathParser release];
}
//如果解析的网页不是utf8编码，如gbk编码，可以先将其转换为utf8编码再对其进行解析
-(NSData *) toUTF8:(NSData *)sourceData {
CFStringRef gbkStr = CFStringCreateWithBytes(NULL, [sourceData bytes], [sourceData length], kCFStringEncodingGB_18030_2000, false);
if (gbkStr == NULL) {
return nil;
} else {
NSString *gbkString = (NSString *)gbkStr;
//根据网页源代码中编码方式进行修改，此处为从gbk转换为utf8
NSString *utf8_String = [gbkString stringByReplacingOccurrencesOfString:@"META http-equiv="Content-Type" content="text/html; charset=GBK""
withString:@"META http-equiv="Content-Type" content="text/html; charset=UTF-8""];
return [utf8_String dataUsingEncoding:NSUTF8StringEncoding];
}
}
