One click crawling result of Java crawler and save it as Excel

Save crawling results as an Excel table
There is no official tutorial for exporting Excel. Here I will send a tutorial for exporting to Excel

Guide bag

I like to use Gradle because of my hobbies, so I'll use the Gradle configuration here

//Reptile pack
compile group: 'us.codecraft', name: 'webmagic-core', version: '0.7.3'
compile group: 'us.codecraft', name: 'webmagic-extension', version: '0.7.3'

//poi package office operation
compile group: 'org.apache.poi', name: 'poi', version: '4.0.1'

maven's word, too

<!-- https://mvnrepository.com/artifact/org.apache.poi/poi -->
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>4.0.1</version>
</dependency>

<!-- Reptile pack -->
<dependency>
    <groupId>us.codecraft</groupId>
    <artifactId>webmagic-core</artifactId>
    <version>0.7.3</version>
</dependency>
<dependency>
    <groupId>us.codecraft</groupId>
    <artifactId>webmagic-extension</artifactId>
    <version>0.7.3</version>
</dependency>

Realization principle

Here I implement the Pipeline interface, which saves the results
Save from this interface
The save() command here adds a synchronized command to prevent thread safety problems when multithreading

Implementation code

Now look at the Java code

import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import us.codecraft.webmagic.*;
import us.codecraft.webmagic.pipeline.Pipeline;
import us.codecraft.webmagic.processor.PageProcessor;
import us.codecraft.webmagic.selector.Selectable;
import us.codecraft.webmagic.utils.FilePersistentBase;


import java.io.FileOutputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;


/**
 * Crawler crawling results export to Excel
 * extends
 *  FilePersistentBase   The parent class of file saving provides convenient operations such as directory creation
 *
 * implements: 
 *  PageProcessor   Page operation of crawler
 *  Pipeline   Result operation of crawling
 */
public class WebmagicAndPoiDemo extends FilePersistentBase implements PageProcessor,Pipeline {
    public WebmagicAndPoiDemo(){
        logger = LoggerFactory.getLogger(getClass());
        site = Site.me().setTimeOut(1000).setRetryTimes(3);
        //Set save path
        setPath("G:\\IdeaProjects\\WebMagicDemo\\Temp\\");
        filename = new SimpleDateFormat("yyyyMMddHHmmss").format(new Date()) +".xls";
        //Create a workbook object
        workbook = new HSSFWorkbook();//You can also set the Name of the sheet here
        //Create sheet object
        sheet = workbook.createSheet("Crawling results");

        //Create rows for sheet
        HSSFRow row = sheet.createRow(rows);
        row.createCell(0).setCellValue("id");
        row.createCell(1).setCellValue("Name");
        row.createCell(2).setCellValue("Connection address");
        rows++;

    }

    private String filename;
    private int rows = 0;
    private HSSFWorkbook workbook;
    private HSSFSheet sheet;
    private Site site;
    private Logger logger;


    @Override
    public Site getSite() {
        return site;
    }


    @Override/** This is the Pipeline method**/
    public void process(ResultItems resultItems, Task task) {
        List<String> hrefs = resultItems.get("href");
        List<String> texts = resultItems.get("text");
        logger.debug(hrefs.toString());
        logger.debug(texts.toString());

        for (int i=0;i<hrefs.size();i++){
            //Create rows for sheet
            HSSFRow row = sheet.createRow(rows);
            row.createCell(0).setCellValue(rows);
            row.createCell(2).setCellValue(hrefs.get(i));
            row.createCell(1).setCellValue(texts.get(i));
            rows++;
        }
        save();
    }
    /** Save table**/
    private synchronized void save() {
        try {
            //Document output
            FileOutputStream out = new FileOutputStream(getFile(this.path).getPath()+"\\"+filename);
            workbook.write(out);
            out.close();
            logger.info(this.path+"\\"+filename+"Storage completed");
        } catch (IOException e) {
            logger.warn("Storage failure", e);
        }
    }


    @Override/** This is the method of PageProcessor**/
    public void process(Page page) {
        Selectable html = page.getHtml();
        Selectable href = html.$(".postTitle2","href");
        Selectable text = html.$(".postTitle2","text");
        page.putField("href",href.all());
        page.putField("text",text.all());
    }


    public static void main(String[] args) {
        //Crawling your own blog posts
        WebmagicAndPoiDemo app = new WebmagicAndPoiDemo();
        Spider.create(app).addPipeline(app)
        .addUrl("https://www.cnblogs.com/xiaoshuai123/").thread(1).run();
    }
}