iOS解析HTML

xml,json都有大量的库来解析，我们如何解析html呢？



TFHpple是一个小型的封装，可以用来解析html，它是对libxml的封装，语法是xpath。

今天我看到一个直接用libxml来解析html，参看：http://www.cocoanetics.com/2011/09/taming-html-parsing-with-libxml-1/#comment-3090 那张图画得一目了然，很值得收藏。这个文章中的源码不能遍历所有的html，我做了一点修改可以将html遍历打印出来

// NSData data contains the document data

// encoding is the NSStringEncoding of the data

// baseURL the documents base URL, i.e. location

CFStringEncoding cfenc = CFStringConvertNSStringEncodingToEncoding(encoding);

CFStringRef cfencstr = CFStringConvertEncodingToIANACharSetName(cfenc);

const char *enc = CFStringGetCStringPtr(cfencstr, 0);

htmlDocPtr _htmlDocument = htmlReadDoc([data bytes],

[[baseURL absoluteString] UTF8String],

enc,

XML_PARSE_NOERROR | XML_PARSE_NOWARNING);

if (_htmlDocument)

{

xmlFreeDoc(_htmlDocument);

}

xmlNodePtr currentNode = (xmlNodePtr)_htmlDocument;

while (currentNode)

{

// output node if it is an element

if (currentNode->type == XML_ELEMENT_NODE)

{

NSMutableArray *attrArray = [NSMutableArray array];

for (xmlAttrPtr attrNode = currentNode->properties; attrNode; attrNode = attrNode->next)

{

xmlNodePtr contents = attrNode->children;

[attrArray addObject:[NSString stringWithFormat:@"%s='%s'", attrNode->name, contents->content]];

}

NSString *attrString = [attrArray componentsJoinedByString:@" "];

if ([attrString length])

{

attrString = [@" " stringByAppendingString:attrString];

}

NSLog(@"<%s%@>", currentNode->name, attrString);

}

else if (currentNode->type == XML_TEXT_NODE)

{

//NSLog(@"%s", currentNode->content);

NSLog(@"%@", [NSString stringWithCString:(const char *)currentNode->content encoding:NSUTF8StringEncoding]);

}

else if (currentNode->type == XML_COMMENT_NODE)

{

NSLog(@"/* %s */", currentNode->name);

}

if (currentNode && currentNode->children)

{

currentNode = currentNode->children;

}

else if (currentNode && currentNode->next)

{

currentNode = currentNode->next;

}

else

{

currentNode = currentNode->parent;

// close node

if (currentNode && currentNode->type == XML_ELEMENT_NODE)

{

NSLog(@"</%s>", currentNode->name);

}

if (currentNode->next)

{

currentNode = currentNode->next;

}

else

{

while(currentNode)

{

currentNode = currentNode->parent;

if (currentNode && currentNode->type == XML_ELEMENT_NODE)

{

NSLog(@"</%s>", currentNode->name);

if (strcmp((const char *)currentNode->name, "table") == 0)

{

NSLog(@"over");

}

}

if (currentNode == nodes->nodeTab[0])

{

break;

}

if (currentNode && currentNode->next)

{

currentNode = currentNode->next;

break;

}

}

}

}

if (currentNode == nodes->nodeTab[0])

{

break;

}

}

不过我还是喜欢用TFHpple，因为它很简单，也好用，但是它的功能不是很完完善。比如，不能获取children node,我就写了两个方法，一个是获取children node,一个是获取所有的contents. 还有node的属性content的key与node's content的key一样，都是@"nodeContent", 正确情况下属性的应是@"attributeContent"，

所以我写了这个方法，同时修改node属性的content key.

NSDictionary *DictionaryForNode2(xmlNodePtr currentNode, NSMutableDictionary *parentResult)

{

NSMutableDictionary *resultForNode = [NSMutableDictionary dictionary];

if (currentNode->name)

{

NSString *currentNodeContent =

[NSString stringWithCString:(const char *)currentNode->name encoding:NSUTF8StringEncoding];

[resultForNode setObject:currentNodeContent forKey:@"nodeName"];

}

if (currentNode->content)

{

NSString *currentNodeContent = [NSString stringWithCString:(const char *)currentNode->content encoding:NSUTF8StringEncoding];

if (currentNode->type == XML_TEXT_NODE)

{

if (currentNode->parent->type == XML_ELEMENT_NODE)

{

[parentResult setObject:currentNodeContent forKey:@"nodeContent"];

return nil;

}

if (currentNode->parent->type == XML_ATTRIBUTE_NODE)

{

[parentResult

setObject:

[currentNodeContent

stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]]

forKey:@"attributeContent"];

return nil;

}

}

}

xmlAttr *attribute = currentNode->properties;

if (attribute)

{

NSMutableArray *attributeArray = [NSMutableArray array];

while (attribute)

{

NSMutableDictionary *attributeDictionary = [NSMutableDictionary dictionary];

NSString *attributeName =

[NSString stringWithCString:(const char *)attribute->name encoding:NSUTF8StringEncoding];

if (attributeName)

{

[attributeDictionary setObject:attributeName forKey:@"attributeName"];

}

if (attribute->children)

{

NSDictionary *childDictionary = DictionaryForNode2(attribute->children, attributeDictionary);

if (childDictionary)

{

[attributeDictionary setObject:childDictionary forKey:@"attributeContent"];

}

}

if ([attributeDictionary count] > 0)

{

[attributeArray addObject:attributeDictionary];

}

attribute = attribute->next;

}

if ([attributeArray count] > 0)

{

[resultForNode setObject:attributeArray forKey:@"nodeAttributeArray"];

}

}

xmlNodePtr childNode = currentNode->children;

if (childNode)

{

NSMutableArray *childContentArray = [NSMutableArray array];

while (childNode)

{

NSDictionary *childDictionary = DictionaryForNode2(childNode, resultForNode);

if (childDictionary)

{

[childContentArray addObject:childDictionary];

}

childNode = childNode->next;

}

if ([childContentArray count] > 0)

{

[resultForNode setObject:childContentArray forKey:@"nodeChildArray"];

}

}

return resultForNode;

}

TFHppleElement.m里加了两个key 常量

NSString * const TFHppleNodeAttributeContentKey = @"attributeContent";

NSString * const TFHppleNodeChildArrayKey = @"nodeChildArray";

并修改获取属性方法为：

- (NSDictionary *) attributes

{

NSMutableDictionary * translatedAttributes = [NSMutableDictionary dictionary];

for (NSDictionary * attributeDict in [node objectForKey:TFHppleNodeAttributeArrayKey]) {

[translatedAttributes setObject:[attributeDict objectForKey:TFHppleNodeAttributeContentKey]

forKey:[attributeDict objectForKey:TFHppleNodeAttributeNameKey]];

}

return translatedAttributes;

}

并添加获取children node 方法：

- (BOOL) hasChildren

{

NSArray *childs = [node objectForKey: TFHppleNodeChildArrayKey];

if (childs)

{

return YES;

}

return NO;

}

- (NSArray *) children

{

if ([self hasChildren])

return [node objectForKey: TFHppleNodeChildArrayKey];

return nil;

}

参看：http://giles-wang.blogspot.com/2011/08/iphoneansi.html

原文：http://blog.csdn.net/favormm/article/details/6794487