Java爬虫怎么实现Jsoupdom方法遍历Document对象
先给出网页地址:
https://wall.alphacoders.com/featured.php?lang=Chinese
主要步骤:
利用Jsoup的connect方法获取Document对象
String html = "https://wall.alphacoders.com/featured.php?lang=Chinese";
Document doc = Jsoup.connect(html).get();
内容过长,就不再显示。
我们以这部分为例:
<ul class="nav nav-pills">
<li><a href="https://alphacoders.com/site/about-us" rel="external nofollow" rel="external nofollow" >About Us</a></li>
<li><a href="https://alphacoders.com/site/faq" rel="external nofollow" rel="external nofollow" >FAQ</a></li>
<li><a href="https://alphacoders.com/site/privacy" rel="external nofollow" rel="external nofollow" >Privacy Policy</a></li>
<li><a href="https://alphacoders.com/site/tos" rel="external nofollow" rel="external nofollow" >Terms Of Service</a></li>
<li><a href="https://alphacoders.com/site/acceptable_use" rel="external nofollow" rel="external nofollow" >Acceptable Use</a></li>
<li><a href="https://alphacoders.com/site/etiquette" rel="external nofollow" rel="external nofollow" >Etiquette</a></li>
<li><a href="https://alphacoders.com/site/advertising" rel="external nofollow" rel="external nofollow" >Advertise With Us</a></li>
<li><a id="change_consent">Change Consent</a></li>
</ul>
我们先找到所有的ul:
Elements elements = doc.getElementsByTag("ul");
输出如下:
<ul class="nav navbar-nav center">
<li> <a title="Submit Wallpapers" href="https://alphacoders.com/site/submit-wallpaper" rel="external nofollow" ><i class="el el-circle-arrow-up"></i> 提交</a> </li>
<li> <a href="https://alphacoders.com/contest" rel="external nofollow" ><i class="el el-gift"></i> 精美奖品</a> </li>
</ul>
<ul class="nav navbar-nav navbar-right center">
<li> <a href="https://www.php.cn/language.php?lang=Chinese" rel="external nofollow" > <img src="https://cache.yisu.com/upload/information/20220517/112/2427.png" alt="Chinese-flag"> 中文 </a> </li>
<li> <a href="https://alphacoders.com/users/login" rel="external nofollow" ><i class="el el-user"></i> 登录</a> </li>
<li> <a href="https://alphacoders.com/users/register" rel="external nofollow" ><i class="el el-edit"></i> 注册</a> </li>
</ul>
<ul class="pagination">
<li class="active"><a href="https://www.php.cn/java-article-539335.html" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >< 上一页</a></li>
<li class="active"><a>1</a></li>
<li><a href="https://wall.alphacoders.com/featured.php?lang=Chinese&page=2" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >2</a></li>
<li><a href="https://wall.alphacoders.com/featured.php?lang=Chinese&page=3" rel="external nofollow" rel="external nofollow" rel="external nofollow" >3</a></li>
<li><a href="https://wall.alphacoders.com/featured.php?lang=Chinese&page=4" rel="external nofollow" rel="external nofollow" rel="external nofollow" >4</a></li>
<li><a href="https://wall.alphacoders.com/featured.php?lang=Chinese&page=5" rel="external nofollow" rel="external nofollow" rel="external nofollow" >5</a></li>
<li><a href="https://wall.alphacoders.com/featured.php?lang=Chinese&page=6" rel="external nofollow" rel="external nofollow" rel="external nofollow" >6</a></li>
<li><a href="https://wall.alphacoders.com/featured.php?lang=Chinese&page=7" rel="external nofollow" rel="external nofollow" rel="external nofollow" >7</a></li>
<li><a href="https://wall.alphacoders.com/featured.php?lang=Chinese&page=8" rel="external nofollow" >8</a></li>
<li><a href="https://wall.alphacoders.com/featured.php?lang=Chinese&page=9" rel="external nofollow" >9</a></li>
<li><a href="https://wall.alphacoders.com/featured.php?lang=Chinese&page=10" rel="external nofollow" >10</a></li>
<li><a>...</a></li>
<li><a href="https://wall.alphacoders.com/featured.php?lang=Chinese&page=319" rel="external nofollow" rel="external nofollow" rel="external nofollow" >319</a></li>
<li><a href="https://wall.alphacoders.com/featured.php?lang=Chinese&page=2" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >下一页 ></a></li>
</ul>
<ul class="pagination">
<li class="active"><a href="https://www.php.cn/java-article-539335.html" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >< 上一页</a></li>
<li class="active"><a>1</a></li>
<li><a href="https://wall.alphacoders.com/featured.php?lang=Chinese&page=2" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >2</a></li>
<li><a href="https://wall.alphacoders.com/featured.php?lang=Chinese&page=3" rel="external nofollow" rel="external nofollow" rel="external nofollow" >3</a></li>
<li><a href="https://wall.alphacoders.com/featured.php?lang=Chinese&page=4" rel="external nofollow" rel="external nofollow" rel="external nofollow" >4</a></li>
<li><a href="https://wall.alphacoders.com/featured.php?lang=Chinese&page=5" rel="external nofollow" rel="external nofollow" rel="external nofollow" >5</a></li>
<li><a href="https://wall.alphacoders.com/featured.php?lang=Chinese&page=6" rel="external nofollow" rel="external nofollow" rel="external nofollow" >6</a></li>
<li><a href="https://wall.alphacoders.com/featured.php?lang=Chinese&page=7" rel="external nofollow" rel="external nofollow" rel="external nofollow" >7</a></li>
<li><a>...</a></li>
<li><a href="https://wall.alphacoders.com/featured.php?lang=Chinese&page=319" rel="external nofollow" rel="external nofollow" rel="external nofollow" >319</a></li>
<li><a href="https://wall.alphacoders.com/featured.php?lang=Chinese&page=2" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >下一页 ></a></li>
</ul>
<ul class="pagination">
<li class="active"><a href="https://www.php.cn/java-article-539335.html" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><< </a></li>
<li class="active"><a href="https://www.php.cn/java-article-539335.html" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >< 上一页</a></li>
<li><a href="https://wall.alphacoders.com/featured.php?lang=Chinese&page=2" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >下一页 ></a></li>
<li><a title="末页 (319)" href="https://wall.alphacoders.com/featured.php?lang=Chinese&page=319" rel="external nofollow" rel="external nofollow" rel="external nofollow" > >></a></li>
</ul>
<ul class="pagination">
<li class="active"><a href="https://www.php.cn/java-article-539335.html" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >1</a></li>
<li><a href="https://wall.alphacoders.com/featured.php?lang=Chinese&page=2" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >2</a></li>
<li><a href="https://wall.alphacoders.com/featured.php?lang=Chinese&page=3" rel="external nofollow" rel="external nofollow" rel="external nofollow" >3</a></li>
<li><a href="https://wall.alphacoders.com/featured.php?lang=Chinese&page=4" rel="external nofollow" rel="external nofollow" rel="external nofollow" >4</a></li>
<li><a href="https://wall.alphacoders.com/featured.php?lang=Chinese&page=5" rel="external nofollow" rel="external nofollow" rel="external nofollow" >5</a></li>
<li><a href="https://wall.alphacoders.com/featured.php?lang=Chinese&page=6" rel="external nofollow" rel="external nofollow" rel="external nofollow" >6</a></li>
<li><a href="https://wall.alphacoders.com/featured.php?lang=Chinese&page=7" rel="external nofollow" rel="external nofollow" rel="external nofollow" >7</a></li>
</ul>
<ul class="nav nav-pills">
<li><a href="https://alphacoders.com/site/about-us" rel="external nofollow" rel="external nofollow" >About Us</a></li>
<li><a href="https://alphacoders.com/site/faq" rel="external nofollow" rel="external nofollow" >FAQ</a></li>
<li><a href="https://alphacoders.com/site/privacy" rel="external nofollow" rel="external nofollow" >Privacy Policy</a></li>
<li><a href="https://alphacoders.com/site/tos" rel="external nofollow" rel="external nofollow" >Terms Of Service</a></li>
<li><a href="https://alphacoders.com/site/acceptable_use" rel="external nofollow" rel="external nofollow" >Acceptable Use</a></li>
<li><a href="https://alphacoders.com/site/etiquette" rel="external nofollow" rel="external nofollow" >Etiquette</a></li>
<li><a href="https://alphacoders.com/site/advertising" rel="external nofollow" rel="external nofollow" >Advertise With Us</a></li>
<li><a id="change_consent">Change Consent</a></li>
</ul>
可以发现class为"nav nav-pills"的只有一个,我们找到它:
Elements elements = doc.getElementsByTag("ul");
//System.out.println(elements);
Element tempElement = null;
for(Element element : elements) {
if (element.className().equals("nav nav-pills")) {
tempElement = element;
//System.out.println(element.className());
break;
}
}
循环遍历这个ul,输出其中每一个li里每一个a的href和rel属性:
Elements li = tempElement.getElementsByTag("li");
for(Element element : li) {
Elements element2 = element.getElementsByTag("a");
for(Element element3 : element2) {
String hrefString = element3.attr("href");
String relString = element3.attr("rel");
if(hrefString != "" && relString != "") {
System.out.println("href="https://www.php.cn/ hrefString " rel="external nofollow" rel="external nofollow" " "rel=" relString);
}
}
}
最终结果:
href=https://alphacoders.com/site/about-us rel=nofollow
href=https://alphacoders.com/site/faq rel=nofollow
href=https://alphacoders.com/site/privacy rel=nofollow
href=https://alphacoders.com/site/tos rel=nofollow
href=https://alphacoders.com/site/acceptable_use rel=nofollow
href=https://alphacoders.com/site/etiquette rel=nofollow
href=https://alphacoders.com/site/advertising rel=nofollow
完整代码:
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;
import java.io.IOException;
import org.jsoup.Jsoup;
/**
* @ClassName: Jsoup_Test
* @description:
* @author: KI
* @Date: 2020年8月17日 下午8:15:14
*/
public class Jsoup_Test {
public static void main(String[] args) throws IOException {
// TODO 自动生成的方法存根
String html = "https://wall.alphacoders.com/featured.php?lang=Chinese";
Document doc = Jsoup.connect(html).get();
System.out.println(doc);
Elements elements = doc.getElementsByTag("ul");
//System.out.println(elements);
Element tempElement = null;
for(Element element : elements) {
if (element.className().equals("nav nav-pills")) {
tempElement = element;
//System.out.println(element.className());
break;
}
}
System.out.println(tempElement);
Elements li = tempElement.getElementsByTag("li");
for(Element element : li) {
Elements element2 = element.getElementsByTag("a");
for(Element element3 : element2) {
String hrefString = element3.attr("href");
String relString = element3.attr("rel");
if(hrefString != "" && relString != "") {
System.out.println("href="https://www.php.cn/ hrefString " rel="external nofollow" rel="external nofollow" " "rel=" relString);
}
}
}
}
}
这篇好文章是转载于:学新通技术网
- 版权申明: 本站部分内容来自互联网,仅供学习及演示用,请勿用于商业和其他非法用途。如果侵犯了您的权益请与我们联系,请提供相关证据及您的身份证明,我们将在收到邮件后48小时内删除。
- 本站站名: 学新通技术网
- 本文地址: /boutique/detail/tanhbjakia
系列文章
更多
同类精品
更多
-
微信小程序没声音怎么办
PHP中文网 06-15 -
excel图片置于文字下方的方法
PHP中文网 06-27 -
怎样阻止微信小程序自动打开
PHP中文网 06-13 -
微信人名旁边有个图标有什么用
PHP中文网 03-11 -
微信提示登录环境异常是什么意思原因
PHP中文网 04-09 -
微信获取用户openid失败怎么办
PHP中文网 03-26 -
photoshop怎么把印章抠出并放在另一张图上
PHP中文网 06-15 -
EhViewer(E绅士)最新版_ehviewer白色版彩色版_Ehviewer显示网络错误怎么办?e站进不去了怎么办
Evanpatchouli 09-19 -
Excel筛选和排序是灰色的怎么办
PHP中文网 06-22 -
photoshop蒙版画笔没反应怎么办
PHP中文网 06-24