In -depth analysis of the HTMLPARSER box in the Java library
In -depth analysis of the HTMLPARSER framework in the Java class library
introduction:
In today's Internet era, the climbing and extraction of webpage content has become increasingly important.HTMLPARSER is a Java class library, which provides a set of powerful and easy to use tools for analysis and processing HTML web pages.This article will focus on the HTMLPARSER framework and provide related Java code examples.
text:
1 Introduction:
HTMLPARSER is an open source library designed to help developers analyze and manipulate the HTML webpage.It provides a variety of functions, including parsing HTML marking, extracting text, traversal HTML elements, and processing HTML forms.HTMLPARSER can be used as an independent library, or it can be used with other Java frameworks such as JSOUP and HTTPClient.
2. Installation and import:
To use HTMLPARSER in the Java project, you need to download the jar file of HTMLPARSER and import it into the project.You can obtain the jar file of HTMLPARSER from HTMLPARSER's official website or Maven central memory.After importing the jar file into the project, you can use the IMPORT statement to import related classes and methods.
For example:
import org.htmlparser.Parser;
import org.htmlparser.util.NodeList;
import org.htmlparser.util.ParserException;
...
3. Analyze HTML webpage:
Using HTMLPARSER can easily analyze the HTML webpage and get the content.Here are a simple example to demonstrate how to use HTMLPARSER to resolve the HTML webpage and extract the link.
try {
// Create a Parser object, submitted to the URL of the HTML webpage
Parser parser = new Parser("http://www.example.com");
// Get all the link elements
NodeList linkNodes = parser.extractAllNodesThatMatch(node -> node.getText().startsWith("<a href="));
// Text and URL that traverses link elements and print links
for (int i = 0; i < linkNodes.size(); i++) {
String linkText = linkNodes.elementAt(i).toPlainTextString();
String linkURL = linkNodes.elementAt(i).getText().split("\"")[1];
System.out.printf ("Link text:%s, link url:%s%n", linktext, linkurl);
}
} catch (ParserException e) {
e.printStackTrace();
}
4. Processing HTML form:
In addition to analyzing the HTML webpage, HTMLPARSER also provides the function of processing the HTML form.The following is an example. How to use HTMLPARSER to fill and submit the HTML form.
try {
// Create a PARSER object and pass in the html webpage containing the form of the form.
Parser parser = new Parser("http://www.example.com/login");
// Get the form element
NodeList formNodes = parser.extractAllNodesThatMatch(node -> node.getText().startsWith("<form "));
// Extract the input field in the form and set the value
NodeList inputNodes = formNodes.elementAt(0).getChildren().extractAllNodesThatMatch(node -> node.getText().startsWith("<input "));
for (int i = 0; i < inputNodes.size(); i++) {
Node inputNode = inputNodes.elementAt(i);
String inputName = inputNode.getText().split("\"")[3];
inputNode.setText(inputName + "=example");
}
// submit Form
Parser formSubmit = new Parser(formNodes.elementAt(0).toHtml());
formSubmit.getConnection().submit();
} catch (ParserException | IOException e) {
e.printStackTrace();
}
Summarize:
HTMLPARSER is a powerful Java class library for analysis and processing HTML web pages.This article provides in -depth analysis of the HTMLPARSER framework, and shows how to use HTMLPARSER to analyze HTML webpage and process HTML forms by example code.Through accurate document analysis and form processing, HTMLPARSER can help developers extract the required information from the HTML webpage to more efficiently.
