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"));
            
    }

}