jsoup HTML parser hello world examples--转

原文地址：http://www.mkyong.com/java/jsoup-html-parser-hello-world-examples/

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.

pom.xml

<dependency>

    <groupId>org.jsoup</groupId>

    <artifactId>jsoup</artifactId>

    <version>1.10.2</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 org.jsoup.Jsoup;

import org.jsoup.nodes.Document;

import org.jsoup.nodes.Element;

import org.jsoup.select.Elements;

import java.io.IOException;

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;

package com.mkyong;

import org.jsoup.Jsoup;

import org.jsoup.nodes.Document;

import org.jsoup.nodes.Element;

import org.jsoup.select.Elements;

import java.io.IOException;

public class HTMLParserExample2 {

    public static void main(String[] args) {

        Document doc;

        try {

            //get all images

            doc = Jsoup.connect("http://yahoo.com").get();

            Elements images = doc.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 simulates 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