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java remove html

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Release： 2023-05-21 11:14:37

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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>

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In the above HTML code,

, ,

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:

When doing natural language processing, it is necessary to remove HTML tags from the text in order to perform operations such as word segmentation and word frequency statistics.
When crawling data, it is necessary to remove HTML tags from the obtained web page content and organize and process the content.

3. How to remove HTML tags in Java

Use regular expressions

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();
}

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In this method, we first define a regular expression <[^>] >, 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.

Using Jsoup

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;
}

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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

When using regular expressions to remove HTML tags, you need to pay attention to the escaping of some special characters, such as "<" and ">" and other symbols Needs to be escaped.
When using Jsoup to remove HTML tags, you need to pay attention to the processing of some special tags. For example, tags such as "script" and "style" need to be processed using different methods.

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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