CLJ Tagsoup framework Best Practice and Examples
CLJ Tagsoup framework Best Practice and Example
Clj tagsoup is a Clojure library for parsing HTML and XML documents.It provides a simple and flexible way to process and query data in HTML or XML documents.This article will introduce the best practice and use examples of the CLJ Tagsoup framework, and provide the corresponding Java code example.
1. Introduce the CLJ TAGSOUP library:
First, we need to introduce the ClJ Tagsoup library in the project.It can be achieved by adding the following dependency items to the Maven or Leiningen configuration file of the project::
Maven:
<dependency>
<groupId>org.clojure</groupId>
<artifactId>tagsoup</artifactId>
<version>1.2.1</version>
</dependency>
Leiningen:
clojure
[org.clojure/tagsoup "1.2.1"]
2. Analyze HTML or XML documents:
To analyze the HTML or XML document, we first need to load the document and pass it to the parser of the CLJ Tagsoup library.The following is an example of analyzing HTML documents and extracting all the links:
import org.ccil.cowan.tagsoup.Parser;
import org.xml.sax.InputSource;
import clojure.java.io.StringReader;
public class TagSoupExample {
public static void main(String[] args) {
String html = "<html><body><a href=\"https://example.com\">Link 1</a><a href=\"https://example.org\">Link 2</a></body></html>";
Parser parser = new Parser();
InputSource inputSource = new InputSource(new StringReader(html));
Object parsed = parser.parse(inputSource);
System.out.println("Parsed HTML document: " + parsed);
}
}
In the above example, we use the `org.ccil.cowan.tagsoup.parser` class to create a parser, and then pass the HTML document as a string to the parser.The parser returns a CLOJURE data structure that represents the parsing document.
3. Query document:
Once we successfully analyze the HTML or XML documents, we can use the functions and macros provided by CLJ Tagsoup to query and process document data.The following is an example of all links in the query and extract all the links in the HTML document:
import org.ccil.cowan.tagsoup.Parser;
import org.xml.sax.InputSource;
import clojure.java.io.StringReader;
import clojure.lang.RT;
import clojure.lang.Var;
public class TagSoupExample {
public static void main(String[] args) {
String html = "<html><body><a href=\"https://example.com\">Link 1</a><a href=\"https://example.org\">Link 2</a></body></html>";
Parser parser = new Parser();
InputSource inputSource = new InputSource(new StringReader(html));
Object parsed = parser.parse(inputSource);
Var require = RT.var("clojure.core", "require");
require.invoke(RT.readFromString("(require '[clojurescript.tag-soup :as tag-soup])"));
Var extractLinks = RT.var("clojure.core", "->");
extractLinks.invoke(parsed, RT.readFromString("(tag-soup/select [[:a :href]])"));
System.out.println("Extracted links: " + extractLinks.get());
}
}
In the above example, first of all, we use the `RT.VAR (" Clojure.Core "," Require ")` function to introduce the `tag-sop` library, and then use the` rt.var ("clojure.core", "->"->")` The function query the parsing document.The `tag-sop/select` function is used to specify the query conditions. Here we extract all the` href` attributes in the label.
4. Further processing data:
Once we successfully extract the required data, we can use various functions and libraries provided by Clojure for further processing and analysis.This can include data conversion, filtration, mapping, sorting and other operations.
import org.ccil.cowan.tagsoup.Parser;
import org.xml.sax.InputSource;
import clojure.java.io.StringReader;
import clojure.lang.RT;
import clojure.lang.Var;
public class TagSoupExample {
public static void main(String[] args) {
String html = "<html><body><a href=\"https://example.com\">Link 1</a><a href=\"https://example.org\">Link 2</a></body></html>";
Parser parser = new Parser();
InputSource inputSource = new InputSource(new StringReader(html));
Object parsed = parser.parse(inputSource);
Var require = RT.var("clojure.core", "require");
require.invoke(RT.readFromString("(require '[clojurescript.tag-soup :as tag-soup])"));
Var extractLinks = RT.var("clojure.core", "->");
Object links = extractLinks.invoke(parsed, RT.readFromString("(tag-soup/select [[:a :href]])"));
Var mapLinks = RT.var("clojure.core", "map");
Object mappedLinks = mapLinks.invoke(RT.readFromString("(fn [link] (str \"https://new-example.com/\" link))"), links);
System.out.println("Mapped links: " + mappedLinks);
}
}
In the above example, we first use the `RT.VAR (" Clojure.Core "," Map ")` function to mappore the extraction link.Here, we add a prefix each link.The output result will be a Clojure sequence that contains the link after mapping.
Summarize:
This article is an example of the best practice and use examples of the ClJ Tagsoup framework.By introducing the CLJ Tagsoup library, parsing HTML or XML documents, querying and processing document data, we can easily extract the required data from HTML or XML documents, and further process and analyze.This makes CLJ Tagsoup a useful tool for processing web crawlers, data capture and data mining.
