html parser

Jsoup, a HTML parser, its “jquery-like” and “regex” selector syntax is very easy to use and flexible enough to get whatever you want. Below are three examples to show you how to use Jsoup to get links, images, page title and “div” element content from a HTML page.

Download jsoup
The jsoup is available in Maven central repository. For non-Maven user, just download it from jsoup website.

  <dependency>
	<groupId>org.jsoup</groupId>
	<artifactId>jsoup</artifactId>
	<version>1.7.1</version>
  </dependency>

1. Grabs All Hyperlinks

This example shows you how to use jsoup to get page’s title and grabs all links from “google.com”.

HTMLParserExample1.java
package com.mkyong;
 
import java.io.IOException;
 
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;
 
public class HTMLParserExample1 {
 
  public static void main(String[] args) {
 
	Document doc;
	try {
 
		// need http protocol
		doc = Jsoup.connect("http://google.com").get();
 
		// get page title
		String title = doc.title();
		System.out.println("title : " + title);
 
		// get all links
		Elements links = doc.select("a[href]");
		for (Element link : links) {
 
			// get the value from href attribute
			System.out.println("\nlink : " + link.attr("href"));
			System.out.println("text : " + link.text());
 
		}
 
	} catch (IOException e) {
		e.printStackTrace();
	}
 
  }
 
}

Output

title : Google

link : http://www.google.com.my/imghp?hl=en&tab=wi
text : Images

link : http://maps.google.com.my/maps?hl=en&tab=wl
text : Maps

//omitted for readability
Note
It’s recommended to specify a “userAgent” in Jsoup, to avoid HTTP 403 error messages.

    Document doc = Jsoup.connect("http://anyurl.com")
	.userAgent("Mozilla")
	.get();

2. Grabs All Images

The second example shows you how to use the Jsoup regex selector to grab all image files (png, jpg, gif) from “yahoo.com”.

HTMLParserExample2.java
package com.mkyong;
 
import java.io.IOException;
 
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;
 
public class HTMLParserExample2 {
 
  public static void main(String[] args) {
 
	Document doc;
	try {
 
		//get all images
		doc = Jsoup.connect("http://yahoo.com").get();
		Elements images = doc2.select("img[src~=(?i)\\.(png|jpe?g|gif)]");
		for (Element image : images) {
 
			System.out.println("\nsrc : " + image.attr("src"));
			System.out.println("height : " + image.attr("height"));
			System.out.println("width : " + image.attr("width"));
			System.out.println("alt : " + image.attr("alt"));
 
		}
 
	} catch (IOException e) {
		e.printStackTrace();
	}
 
  }
 
}

Output

src : http://l.yimg.com/a/i/mntl/ww/events/p.gif
height : 50
width : 202
alt : Yahoo!

src : http://l.yimg.com/a/i/ww/met/intl_flag_icons/20111011/my_flag.gif
height : 
width : 
alt :

//omitted for readability

3. Get Meta elements

The last example simulate an offline HTML page and use jsoup to parse the content. It grabs the “meta” keyword and description, and also the div element with the id of “color”.

HTMLParserExample3.java
package com.mkyong;
 
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
 
public class HTMLParserExample3 {
 
  public static void main(String[] args) {
 
	StringBuffer html = new StringBuffer();
 
	html.append("<!DOCTYPE html>");
	html.append("<html lang=\"en\">");
	html.append("<head>");
	html.append("<meta charset=\"UTF-8\" />");
	html.append("<title>Hollywood Life</title>");
	html.append("<meta name=\"description\" content=\"The latest entertainment news\" />");
	html.append("<meta name=\"keywords\" content=\"hollywood gossip, hollywood news\" />");
	html.append("</head>");
	html.append("<body>");
	html.append("<div id='color'>This is red</div> />");
	html.append("</body>");
	html.append("</html>");
 
	Document doc = Jsoup.parse(html.toString());
 
	//get meta description content
	String description = doc.select("meta[name=description]").get(0).attr("content");
	System.out.println("Meta description : " + description);
 
	//get meta keyword content
	String keywords = doc.select("meta[name=keywords]").first().attr("content");
	System.out.println("Meta keyword : " + keywords);
 
	String color1 = doc.getElementById("color").text();
	String color2 = doc.select("div#color").get(0).text();
 
	System.out.println(color1);
	System.out.println(color2);
 
  }
 
}

Output

Meta description : The latest entertainment news
Meta keyword : hollywood gossip, hollywood news
This is red
This is red

4. Grabs Form Inputs

This code snippets shows you how to use Jsoup to grab HTML form inputs (name and value). For detail usage, please refer to this automate login a website with Java.

public void getFormParams(String html){
 
	Document doc = Jsoup.parse(html);
 
	//HTML form id
	Element loginform = doc.getElementById("your_form_id");
 
	Elements inputElements = loginform.getElementsByTag("input");
 
	List<String> paramList = new ArrayList<String>();
	for (Element inputElement : inputElements) {
		String key = inputElement.attr("name");
		String value = inputElement.attr("value");
	}
 
}

5. Get Fav Icon

This code shows you how to use Jsoup to page’s favourite icon.

jSoupExample.java
package com.mkyong;
 
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
 
public class jSoupExample {
 
    public static void main(String[] args) {
 
	StringBuffer html = new StringBuffer();
 
	html.append("<html lang=\"en\">");
	html.append("<head>");
	html.append("<link rel=\"icon\" href=\"http://example.com/image.ico\" />");		
	//html.append("<meta content=\"/images/google_favicon_128.png\" itemprop=\"image\">");
	html.append("</head>");
	html.append("<body>");
	html.append("something");
	html.append("</body>");
	html.append("</html>");
 
	Document doc = Jsoup.parse(html.toString());
 
	String fav = "";
 
	Element element = doc.head().select("link[href~=.*\\.(ico|png)]").first();
	if(element==null){
 
		element = doc.head().select("meta[itemprop=image]").first();
		if(element!=null){
			fav = element.attr("content");
		}
	}else{
		fav = element.attr("href");
	}
	System.out.println(fav);
  }
 
}

Output

http://example.com/image.ico

References

Tags :
Founder of Mkyong.com, love Java and open source stuff. Follow him on Twitter, or befriend him on Facebook or Google Plus. If you like my tutorials, consider making a donation to the charity, thanks.

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