java 强悍的html解析器--jsoup

今天学习了一个java的html解析器(jsoup)，以前一直使用htmlParser,感觉htmlParser处理html还可以，然而jsoup更强大，简单来说jsoup就是一个java版的jquery，个人认为很相似，方法名和选择器都很相像，比如jquery比较常用的方法：html()、text()、attr()等，如果熟悉jquery的话那学习jsoup就非常简单了，要是不熟悉jquery就多做些例子看看官方提供的教材和api也很快能学会的。
官方网站： http://jsoup.org/
我的网站“导航189”在“热帖”板块抓取天涯的数据时候就是使用jsoup来解析html http://www.dh189.com/
截图：


在附件中有：jsoup-1.2.3.jar jsoup-1.2.3-javadoc.jar jsoup-1.2.3-sources.jar 三个文件

开始使用jsoup:

import java.net.URL;

import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;

public class JsoupTest {

	public static void main(String[] args) throws Exception {
		URL url = new URL("http://www.dh189.com/");
		Document doc = Jsoup.parse(url, 3 * 1000);
		//获取所有的链接
		Elements test = doc.select("a");
		for (Element element : test) {
			//element.outerHtml() 和  element.toString()效果一样
			System.out.println("链接源代码：" + element.outerHtml());
			System.out.println("链接地址：" + element.attr("href") + "  链接文本：" + element.text());
		}

	}
}

jsoup选择器支持如下：

Pattern	Example
*	*
E	h1
ns E	fb name finds elements
E#id	div#wrap, #logo
E.class	div.left, .result
E[attr]	a[href], [title]
E[^attrPrefix]	[^data-], div[^data-]
E[attr=val]	img[width=500], a[rel=nofollow]
E[attr^=valPrefix]	a[href^=http:]
E[attr$=valSuffix]	img[src$=.png]
E[attr*=valContaining]	a[href*=/search/]
E[attr~=regex]	img[src~=(?i)\\.(png\jpe?g)] div.header[title]
E F	div a, .logo h1
E > F	ol > li
E + F	li + li, div.head + div
E ~ F	h1 ~ p
E, F, G	a[href], div, h3
E:lt(n)	td:lt(3) finds the first 2 cells of each row
E:gt(n)	td:gt(1) finds cells after skipping the first two
E:eq(n)	td:eq(0) finds the first cell of each row
E:has(selector)	div:has(p) finds divs that contain p elements
E:contains(text)	p:contains(jsoup) finds p elements containing the text "jsoup".
E:matches(regex)	td:matches(\\d+) finds table cells containing digits. div:matches((?i)login) finds divs containing the text, case insensitively.

官方提供的例子links：

package org.jsoup.examples;

import org.apache.commons.lang.Validate;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.Jsoup;
import org.jsoup.select.Elements;

import java.net.URL;
import java.io.IOException;

/**
 * Example program to list links from a URL.
 */
public class ListLinks {
    public static void main(String[] args) throws IOException {
        Validate.isTrue(args.length == 1, "usage: supply url to fetch");
        URL url = new URL(args[0]);
        print("Fetching %s...", url.toExternalForm());

        Document doc = Jsoup.parse(url, 3*1000);
        Elements links = doc.select("a[href]");
        Elements media = doc.select("[src]");
        Elements imports = doc.select("link[href]");

        print("\nMedia: (%d)", media.size());
        for (Element src : media) {
            if (src.tagName().equals("img"))
                print(" * %s: <%s> %sx%s (%s)",
                        src.tagName(), src.attr("abs:src"), src.attr("width"), src.attr("height"),
                        trim(src.attr("alt"), 20));
            else
                print(" * %s: <%s>", src.tagName(), src.attr("abs:src"));
        }

        print("\nImports: (%d)", imports.size());
        for (Element link : imports) {
            print(" * %s <%s> (%s)", link.tagName(),link.attr("abs:href"), link.attr("rel"));
        }

        print("\nLinks: (%d)", links.size());
        for (Element link : links) {
            print(" * a: <%s>  (%s)", link.attr("abs:href"), trim(link.text(), 35));
        }
    }

    private static void print(String msg, Object... args) {
        System.out.println(String.format(msg, args));
    }

    private static String trim(String s, int width) {
        if (s.length() > width)
            return s.substring(0, width-1) + ".";
        else
            return s;
    }
}

其他的一些例子:

Element div = doc.select("div").first(); // <div></div>
div.text("five > four"); // <div>five &gt; four</div>
div.prepend("First ");
div.append(" Last");
// now: <div>First five &gt; four Last</div>

File input = new File("/tmp/input.html"); 
Document doc = Jsoup.parse(input, "UTF-8", "http://example.com/"); 
Elements links = doc.select("a[href]"); // a with href 
Elements pngs = doc.select("img[src$=.png]");  // img with src ending .png 
Element masthead = doc.select("div.masthead").first(); // div with class=masthead 
Elements resultLinks = doc.select("h3.r > a"); // direct a after h3