请求网页，对返回的数据进行提取_提取网页返回的地址-优快云博客

本文介绍如何请求网页并提取所需数据。首先讲解HTTP请求的基本原理，然后通过实例演示使用Python的requests库发送GET和POST请求。接着，讨论如何利用BeautifulSoup库解析HTML文档，提取关键信息。最后，提到了反爬虫策略和应对方法，以及如何遵守网站的robots.txt文件规定。

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package cn.tongdun.preserver.etl;

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 java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class test2 {

    //请求网页，对返回的数据进行提取
    //返回网页信息格式 ：{"company1":"济南吉隆锻造厂","company2":"济南章丘烟台西蒙西锻造有限公司","similarity":38}
    //提取内容：similarity的值，这个例子是 38


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

        //创建httpClient实例
        CloseableHttpClient  httpClient = HttpClients.createDefault();
        //装结果
        List<String> valueStrList = new ArrayList<String>();
        //装的是文件中的每一行
        List<String> fileList = readerFile();
        for (int i = 0; i<fileList.size();i++){

            //创建httpGet实例
            HttpGet httpGet = new HttpGet(fileList.get(i));
            //执行http get请求
            CloseableHttpResponse response = httpClient.execute(httpGet);
            //获取返回实体
            HttpEntity entity = response.getEntity();
            //获取网页内容
            String str = EntityUtils.toString(entity, "utf-8");
            System.out.println("网页内容："+str);
            //关闭流
            response.close();
            //正则提取返回网页的结果
            String returnValue = regx("\\d+", str);
            valueStrList.add(returnValue);

        }

        //循环输出结果
        for (int j = 0 ;j<valueStrList.size();j++){
            System.out.println(valueStrList.get(j));
        }
    }

    // 将文件中读取的每行数据放入list
    public static List<String> readerFile() {
        List<String> fileStrList = new ArrayList<String>();
        BufferedReader br = null;
        try {

            br = new BufferedReader(new InputStreamReader(new FileInputStream("C:\\Users\\86184\\Desktop\\test.txt"), "gbk"));
            String line = br.readLine();
            while (null != line) {
                fileStrList.add(line);
                line = br.readLine();

            }
        } catch (Exception e) {
            e.printStackTrace();
        }

        System.out.println("读取的数据是："+fileStrList.toString());
        return fileStrList;
    }


    //正则匹配数字，并返回最后一个匹配到的数字
    public static String regx(String reg ,String str){

        List<String> strsList = new ArrayList<String>();
        Pattern p = Pattern.compile(reg); //写匹配规则的模式
        Matcher m = p.matcher(str); //字符串和规则匹配
        while (m.find()) { //返回true或false，是否有匹配的子串
            strsList.add(m.group()); //循环，通过group拿出匹配的子串
        }
        return strsList.get(strsList.size()-1);
    }

}