java通过Jsoup爬取网页过程详解

<!--java爬虫-->
    <dependency>
      <groupId>org.jsoup</groupId>
      <artifactId>jsoup</artifactId>
      <version>1.10.3</version>
    </dependency>
    <!--httpclient依赖-->
    <dependency>
      <groupId>org.apache.httpcomponents</groupId>
      <artifactId>httpclient</artifactId>
    </dependency>

package com.taotao.entity;
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;

import java.io.IOException;

/**
 * Author: TaoTao 2019/9/26
 */
public class intefaceTest {
  public static void main(String[] args) throws IOException {
    CloseableHttpClient httpClient = HttpClients.createDefault();//创建httpClient
    HttpGet httpGet = new HttpGet("http://www.cnblogs.com/");//创建httpget实例

    CloseableHttpResponse response = httpClient.execute(httpGet);//执行get请求
    HttpEntity entity = response.getEntity();//获取返回实体
    String content = EntityUtils.toString(entity,"utf-8");//网页内容
    response.close();//关闭流和释放系统资源

    Jsoup.parse(content);
    Document doc = Jsoup.parse(content);//解析网页得到文档对象
    Elements elements = doc.getElementsByTag("title");//获取tag是title的所有dom文档
    Element element = elements.get(0);//获取第一个元素
    String title = element.text(); //.html是返回html
    System.out.println("网页标题："+title);
    Element element1 = doc.getElementById("site_nav_top");//获取id=site_nav_top标签
    String str = element1.text();
    System.out.println("str:"+str);
  }
}