jsoup要点记录

查找dom元素

• getElementById: 根据id查询
• getElementsByTag: 根据tag名称查询
• getElementsByClass: 根据样式class名称查询
• getElementsByAttribute: 根据属性名查询
• getElementsByAttributeValue: 根据属性名和属性值查询

实例代码

import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;

public class Demo01 {

	public static void main(String[] args) throws Exception {
	
		/*用heepclient发起请求获取页面*/
		CloseableHttpClient httpClient = HttpClients.createDefault();
		HttpGet httpGet = new HttpGet("https://www.cnblogs.com/");
		CloseableHttpResponse response = httpClient.execute(httpGet);
		HttpEntity entity = response.getEntity();
		String content = EntityUtils.toString(entity, "utf-8");
		response.close();
		Document doc = Jsoup.parse(content); //用jsoup解析
		
		//通过标签名称查询
		Elements elements = doc.getElementsByTag("title");
		Element element = elements.get(0);
		String title = element.text();
		System.out.println("网页标题：" + title);
		
		//获取首个标题标签内容
		Element titleElement = doc.getElementsByTag("title").first(); 
		System.out.println("首个标题： " + titleElement.text());
		
		//通过id查询
		Element idElement = doc.getElementById("site_nav_top"); 
		System.out.println("id查询：" + idElement.text());
		
		//通过class样式获取查询
		Elements itemElements = doc.getElementsByClass("post_item"); 
		System.out.println("**********样式查询**********");
		for(Element e: itemElements) {
			System.out.println(e.text());
			System.out.println("-------");
		}
	
		//属性名称查询
		Elements attrElements = doc.getElementsByAttribute("width");
		System.out.println("**********属性查询**********");
		for(Element e: attrElements) {
			System.out.println(e.toString());
		}
	
		//属性名称和属性值查询
		Elements attrValueElements = doc.getElementsByAttributeValue("target", "_blank");
		System.out.println("**********属性和属性值查询**********");
		for(Element e: attrValueElements) {
			System.out.println(e.toString());
		}
		
	}

}

查找dom元素属性值

实例代码

import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;


public class Demo2 {

	public static void main(String[] args) throws Exception {

		/*用heepclient发起请求获取页面*/
		CloseableHttpClient httpClient = HttpClients.createDefault();
		HttpGet httpGet = new HttpGet("https://www.cnblogs.com/");
		CloseableHttpResponse response = httpClient.execute(httpGet);
		HttpEntity entity = response.getEntity();
		String content = EntityUtils.toString(entity, "utf-8");
		response.close();
		Document doc = Jsoup.parse(content); //用jsoup解析

		
		//获取带有href属性的a标签
		Elements attrElements = doc.select("a[href]");
		System.out.println("**********获取属性值**********");
		for(Element e: attrElements) {
			System.out.println(e.toString());
			System.out.println("-------");
		}
		
		//查找拓展名为gif的img标签
		Elements imgElements = doc.select("img[src$=.gif]");
		System.out.println("**********带有拓展名查询**********");
		for(Element e: imgElements) {
			System.out.println(e.toString());
		}
	}

}

使用选择器查询

Jsoup 支持css，jquery的选择器

实例代码

import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;


public class Demo03 {

	public static void main(String[] args) throws Exception {
		
		/*用heepclient发起请求获取页面*/
		CloseableHttpClient httpClient = HttpClients.createDefault();
		HttpGet httpGet = new HttpGet("https://www.cnblogs.com/");
		CloseableHttpResponse response = httpClient.execute(httpGet);
		HttpEntity entity = response.getEntity();
		String content = EntityUtils.toString(entity, "utf-8");
		response.close();
		Document doc = Jsoup.parse(content); //用jsoup解析
		
		//通过选择器查询
		Elements linkElements = doc.select(".headline ul .editor_pick a");
		System.out.println("**********选择器查询**********");
		for(Element e: linkElements) {
			System.out.println(e.toString());
			System.out.println("地址： " + e.attr("href"));
			System.out.println("-------");
		}
		
		Element linkElement = doc.select(".headline ul li").first();
		System.out.println("文本： " + linkElement.text());
		System.out.println("html: " + linkElement.html());
		System.out.println("class属性值： " + linkElement.attr("class"));
			
	}

}