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With the development of the Internet, we often need to obtain data from web pages or web crawlers to crawl data. However, web pages often contain a large number of HTML tags and other special symbols, which is very inconvenient for data processing. This article will introduce how to use Java to remove HTML tags to make the data easier to process.
1. What are HTML tags?
HTML (Hyper Text Markup Language) is a standard language for creating web pages. HTML language contains a series of tags, which describe and display text, images, videos and other content through a combination of tags and attributes. For example, the following is a simple HTML page:
<!DOCTYPE HTML> <html> <head> <meta charset="utf-8" /> <title>Example</title> </head> <body> <h1>Welcome to my page</h1> <p>Here are some <a href="http://www.example.com">links</a> you might find interesting:</p> <ul> <li><a href="http://www.example.com/link1">Link 1</a></li> <li><a href="http://www.example.com/link2">Link 2</a></li> <li><a href="http://www.example.com/link3">Link 3</a></li> </ul> </body> </html>
In the above HTML code, 4a249f0d628e2318394fd9b75b4636b1, e388a4556c0f65e1904146cc1a846bee, , ff6d136ddc5fdfeffaf53ff6ee95f185, 25edfb22a4f469ecb59f1190150159c6 and other tags are HTML tags , they define the structure, style and behavior of text, images, links and other content.
2. Why should we remove HTML tags?
In practical applications, we often do not want to process the tags contained in HTML, but only process their content. For example:
3. How to remove HTML tags in Java
Using regular expressions to remove HTML tags in Java is A relatively common method. We can use regular expressions to match and remove HTML tags, leaving only the text content contained within them. For example:
public static String removeHtmlTags(String html) { // 定义正则表达式 String regEx_html="<[^>]+>"; // 编译正则表达式 Pattern pattern = Pattern.compile(regEx_html); // 匹配正则表达式 Matcher matcher = pattern.matcher(html); // 去除标签 String res = matcher.replaceAll(""); return res.trim(); }
In this method, we first define a regular expression 549a3fd9a3c62568d8b32cd8627105c3] >
, which means that all HTML tags need to be matched. Then use the Pattern.compile() method to compile the regular expression into a Pattern object, and finally use the Matcher.replaceAll() method to perform matching and replacement operations to remove all HTML tags.
Jsoup is a Java library for HTML parsing, which can help us easily remove HTML tags. Using this library, we only need to pass the HTML text as a parameter into the Jsoup.parse() method and use the text() method to extract the text content to remove the HTML tags. For example:
public static String removeHtmlTags(String html) { // 解析HTML Document doc = Jsoup.parse(html); // 去除标签 String res = doc.text(); return res; }
In this method, we first use the Jsoup.parse() method to parse the HTML text into a Document object, and then use the text() method to extract the text content, thereby converting the HTML tags Remove.
4. Notes
In short, removing HTML tags is one of the operations we often need to perform. This article introduces two methods for removing HTML tags in Java. Readers can choose the corresponding method according to actual needs. Whether using regular expressions or Jsoup, we can easily remove HTML tags, making subsequent data processing and analysis easier.
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