HTML Parser

HTMLParser是一款Java库,用于以线性或嵌套方式解析HTML。它主要用于数据提取和网页转换,支持过滤器、访问者模式及自定义标签等功能。无论是简单的文本提取还是复杂的网页转换任务,HTMLParser都能提供强大的支持。

摘要生成于 C知道 ,由 DeepSeek-R1 满血版支持, 前往体验 >

http://htmlparser.sourceforge.net/

[color=blue]HTML Parser is a Java library used to parse HTML in either a linear or nested fashion. Primarily used for transformation or extraction, [/color]it features filters, visitors, custom tags and easy to use JavaBeans. It is a fast, robust and well tested package.
Welcome to the homepage of HTMLParser - a super-fast real-time parser for real-world HTML. What has attracted most developers to HTMLParser has been its simplicity in design, speed and ability to handle streaming real-world html.

The two fundamental use-cases that are handled by the parser are extraction and transformation (the syntheses use-case, where HTML pages are created from scratch, is better handled by other tools closer to the source of data). While prior versions concentrated on data extraction from web pages, Version 1.4 of the HTMLParser has substantial improvements in the area of transforming web pages, with simplified tag creation and editing, and verbatim toHtml() method output.

In general, to use the HTMLParser you will need to be able to write code in the Java programming language. Although some example programs are provided that may be useful as they stand, it's more than likely you will need (or want) to create your own programs or modify the ones provided to match your intended application.

[color=blue]To use the library, you will need to add either the htmllexer.jar or htmlparser.jar to your classpath when compiling and running.[/color] The htmllexer.jar provides low level access to generic string, remark and tag nodes on the page in a linear, flat, sequential manner. The htmlparser.jar, which includes the classes found in htmllexer.jar, provides access to a page as a sequence of nested differentiated tags containing string, remark and other tag nodes. So where the output from calls to the lexer nextNode() method might be:

<html>
<head>
<title>

"Welcome"
</title>
</head>
<body>
etc...

The output from the parser NodeIterator would nest the tags as children of the <html>, <head> and other nodes (here represented by indentation):


<html>
<head>
<title>
"Welcome"
</title>
</head>
<body>

etc...

The parser attempts to balance opening tags with ending tags to present the structure of the page, while the lexer simply spits out nodes. If your application requires only modest structural knowledge of the page, and is primarily concerned with individual, isolated nodes, you should consider using the lightweight lexer. But if your application requires knowledge of the nested structure of the page, for example processing tables, you will probably want to use the full parser.

[color=violet]Extraction[/color]
Extraction encompasses all the information retrieval programs that are not meant to preserve the source page. This covers uses like:
text extraction, for use as input for text search engine databases for example
link extraction, for crawling through web pages or harvesting email addresses
screen scraping, for programmatic data input from web pages
resource extraction, collecting images or sound
a browser front end, the preliminary stage of page display
link checking, ensuring links are valid
site monitoring, checking for page differences beyond simplistic diffs
There are several facilities in the HTMLParser codebase to help with extraction, including filters, visitors and JavaBeans.

[color=violet]Transformation[/color]
Transformation includes all processing where the input and the output are HTML pages. Some examples are:
URL rewriting, modifying some or all links on a page
site capture, moving content from the web to local disk
censorship, removing offending words and phrases from pages
HTML cleanup, correcting erroneous pages
ad removal, excising URLs referencing advertising
conversion to XML, moving existing web pages to XML
During or after reading in a page, operations on the nodes can accomplish many transformation tasks "in place", which can then be output with the toHtml() method. Depending on the purpose of your application, you will probably want to look into node decorators, visitors, or custom tags in conjunction with the PrototypicalNodeFactory.
评论
添加红包

请填写红包祝福语或标题

红包个数最小为10个

红包金额最低5元

当前余额3.43前往充值 >
需支付:10.00
成就一亿技术人!
领取后你会自动成为博主和红包主的粉丝 规则
hope_wisdom
发出的红包
实付
使用余额支付
点击重新获取
扫码支付
钱包余额 0

抵扣说明:

1.余额是钱包充值的虚拟货币,按照1:1的比例进行支付金额的抵扣。
2.余额无法直接购买下载,可以购买VIP、付费专栏及课程。

余额充值