java 爬取51job招聘信息

本案例是基于webmagic和jsoup对51job招聘信息的爬取，并将爬取到的数据存入mysql数据库中。

Jsoup

jsoup 是一款Java 的HTML解析器，可直接解析某个URL地址、HTML文本内容。它提供了一套非常省力的API，可通过DOM，CSS以及类似于jQuery的操作方法来取出和操作数据。

jsoup的主要功能如下：

1. 从一个URL，文件或字符串中解析HTML；
2. 使用DOM或CSS选择器来查找、取出数据；
3. 可操作HTML元素、属性、文本；

WebMagic

WebMagic是一个简单灵活的Java爬虫框架。底层基于HttpClient和Jsoup。

WebMagic项目代码分为核心和扩展两部分。核心部分(webmagic-core)是一个精简的、模块化的爬虫实现，而扩展部分则包括一些便利的、实用性的功能。

WebMagic的设计目标是尽量的模块化，并体现爬虫的功能特点。这部分提供非常简单、灵活的API，在基本不改变开发模式的情况下，编写一个爬虫。

扩展部分(webmagic-extension)提供一些便捷的功能，例如注解模式编写爬虫等。同时内置了一些常用的组件，便于爬虫开发。

业务分析

要实现的是爬取https://www.51job.com/上的招聘信息。只爬取java招聘的信息。

---

点击职位详情页，我们分析发现详情页还有一些数据需要抓取：
职位、公司名称、工作地点、薪资、发布时间、职位信息、公司联系方式、公司信息


根据以上信息，设计数据库表

CREATE TABLE `job_info` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '主键id',
  `company_name` varchar(100) DEFAULT NULL COMMENT '公司名称',
  `company_addr` varchar(200) DEFAULT NULL COMMENT '公司联系方式',
  `company_info` text COMMENT '公司信息',
  `job_name` varchar(100) DEFAULT NULL COMMENT '职位名称',
  `job_addr` varchar(50) DEFAULT NULL COMMENT '工作地点',
  `job_info` text COMMENT '职位信息',
  `salary_min` int(10) DEFAULT NULL COMMENT '薪资范围，最小',
  `salary_max` int(10) DEFAULT NULL COMMENT '薪资范围，最大',
  `url` varchar(150) DEFAULT NULL COMMENT '招聘信息详情页',
  `time` varchar(10) DEFAULT NULL COMMENT '职位最近发布时间',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8 COMMENT='招聘信息';

环境搭建

pom.xml 导入jar包坐标

<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0modelVersion>
    <parent>
        <groupId>org.springframework.bootgroupId>
        <artifactId>spring-boot-starter-parentartifactId>
        <version>2.1.0.RELEASEversion>
        <relativePath/> 
    parent>

    <groupId>sunyuqi.comgroupId>
    <artifactId>crawlerjob_projectartifactId>
    <version>1.0-SNAPSHOTversion>

    <properties>
        <java.version>9java.version>
    properties>

    <dependencies>
        
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-webartifactId>
        dependency>

        
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-data-jpaartifactId>
        dependency>

        
        <dependency>
            <groupId>mysqlgroupId>
            <artifactId>mysql-connector-javaartifactId>
            <version>8.0.11version>
        dependency>

        
        <dependency>
            <groupId>us.codecraftgroupId>
            <artifactId>webmagic-coreartifactId>
            <version>0.7.3version>
            <exclusions>
                <exclusion>
                    <groupId>org.slf4jgroupId>
                    <artifactId>slf4j-log4j12artifactId>
                exclusion>
            exclusions>
        dependency>
        
        <dependency>
            <groupId>us.codecraftgroupId>
            <artifactId>webmagic-extensionartifactId>
            <version>0.7.3version>
        dependency>

        
        <dependency>
            <groupId>com.google.guavagroupId>
            <artifactId>guavaartifactId>
            <version>16.0version>
        dependency>

        
        <dependency>
            <groupId>org.apache.commonsgroupId>
            <artifactId>commons-lang3artifactId>
        dependency>

        
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-testartifactId>
        dependency>

    dependencies>
project>

编写application.properties配置文件

#DB Configuration:
spring.datasource.driverClassName=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/crawler?useSSL=false&serverTimezone=UTC
spring.datasource.username=root
spring.datasource.password=qwe123

#JPA Configuration:
spring.jpa.database=MySQL
spring.jpa.show-sql=true

编写实体类

package job.domain;

import javax.persistence.*;

@Entity
@Table(name = "job_info")
public class JobInfo {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String companyName;
    private String companyAddr;
    private String companyInfo;
    private String jobName;
    private String jobAddr;
    private String jobInfo;
    private Integer salaryMin;
    private Integer salaryMax;
    private String url;
    private String time;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getCompanyName() {
        return companyName;
    }

    public void setCompanyName(String companyName) {
        this.companyName = companyName;
    }

    public String getCompanyAddr() {
        return companyAddr;
    }

    public void setCompanyAddr(String companyAddr) {
        this.companyAddr = companyAddr;
    }

    public String getCompanyInfo() {
        return companyInfo;
    }

    public void setCompanyInfo(String companyInfo) {
        this.companyInfo = companyInfo;
    }

    public String getJobName() {
        return jobName;
    }

    public void setJobName(String jobName) {
        this.jobName = jobName;
    }

    public String getJobAddr() {
        return jobAddr;
    }

    public void setJobAddr(String jobAddr) {
        this.jobAddr = jobAddr;
    }

    public String getJobInfo() {
        return jobInfo;
    }

    public void setJobInfo(String jobInfo) {
        this.jobInfo = jobInfo;
    }

    public Integer getSalaryMin() {
        return salaryMin;
    }

    public void setSalaryMin(Integer salaryMin) {
        this.salaryMin = salaryMin;
    }

    public Integer getSalaryMax() {
        return salaryMax;
    }

    public void setSalaryMax(Integer salaryMax) {
        this.salaryMax = salaryMax;
    }

    public String getUrl() {
        return url;
    }

    public void setUrl(String url) {
        this.url = url;
    }

    public String getTime() {
        return time;
    }

    public void setTime(String time) {
        this.time = time;
    }

    @Override
    public String toString() {
        return "JobInfo{" +
                "id=" + id +
                ", companyName='" + companyName + '\'' +
                ", companyAddr='" + companyAddr + '\'' +
                ", companyInfo='" + companyInfo + '\'' +
                ", jobName='" + jobName + '\'' +
                ", jobAddr='" + jobAddr + '\'' +
                ", jobInfo='" + jobInfo + '\'' +
                ", salaryMin=" + salaryMin +
                ", salaryMax=" + salaryMax +
                ", url='" + url + '\'' +
                ", time='" + time + '\'' +
                '}';
    }
}

编写Dao

package job.dao;

import job.domain.JobInfo;
import org.springframework.data.jpa.repository.JpaRepository;

public interface JobInfoDao extends JpaRepository<JobInfo, Long> {
}

编写Service

Service接口

package job.service;

import job.domain.JobInfo;
import org.springframework.data.domain.Page;

import java.util.List;

public interface JobInfoService {

    /**
     * 保存工作信息
     *
     * @param jobInfo
     */
    public void save(JobInfo jobInfo);


    /**
     * 根据条件查询工作信息
     *
     * @param jobInfo
     * @return
     */
    public List<JobInfo> findJobInfo(JobInfo jobInfo);

    /**
     * 分页查询数据
     * @param page
     * @param rows
     * @return
     */
    Page<JobInfo> findJobInfoByPage(int page, int rows);
}

Service实现类

package job.service.impl;

import job.dao.JobInfoDao;
import job.domain.JobInfo;
import job.service.JobInfoService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Example;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.List;

@Service
public class JobInfoServiceImpl implements JobInfoService {

    @Autowired
    private JobInfoDao jobInfoDao;

    @Override
    @Transactional
    public void save(JobInfo jobInfo) {
        //根据url和发布时间查询数据
        JobInfo param = new JobInfo();
        param.setUrl(jobInfo.getUrl());
        param.setTime(jobInfo.getTime());

        //执行查询
        List<JobInfo> list = this.findJobInfo(param);

        //判断查询结果是否为空
        if (list.size() == 0) {
            //如果查询结果为空，表示招聘信息数据不存在，或者已经更新了，需要新增或者更新数据库
            this.jobInfoDao.saveAndFlush(jobInfo);
        }
    }

    @Override
    public List<JobInfo> findJobInfo(JobInfo jobInfo) {
        //设置查询条件
        Example example = Example.of(jobInfo);
        //执行查询
        List list = this.jobInfoDao.findAll(example);
        return list;
    }

    @Override
    public Page<JobInfo> findJobInfoByPage(int page, int rows) {
        Page<JobInfo> JobInfos = this.jobInfoDao.findAll(PageRequest.of(page - 1, rows));
        return JobInfos;
    }
}

编写引导类

package job;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.scheduling.annotation.EnableScheduling;

@SpringBootApplication
@EnableScheduling//开启定时任务
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

自定义Pipeline

SpringDataPipeline

package job.task;

import job.domain.JobInfo;
import job.service.JobInfoService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import us.codecraft.webmagic.ResultItems;
import us.codecraft.webmagic.Task;
import us.codecraft.webmagic.pipeline.Pipeline;

@Component
public class SpringDataPipeline  implements Pipeline {

    @Autowired
    private JobInfoService jobInfoService;

    @Override
    public void process(ResultItems resultItems, Task task) {
        //获取封装好的招聘详情对象
        JobInfo jobInfo = resultItems.get("jobInfo");
        //判断数据是否不为空
        if (jobInfo != null) {
            //如果不为空把数据保存到数据库中
            this.jobInfoService.save(jobInfo);
        }
    }
}

计算薪水工具类

MathSalary.java

package job.task;

public class MathSalary {
    /**
     * 获取薪水范围
     * @param salaryStr
     * @return
     */
    public static Integer[] getSalary(String salaryStr) {
        if (salaryStr==null || "".equals(salaryStr))
        {
            return new Integer[]{0,0};
        }
        Integer[] salary = new Integer[2];
        
        String date = salaryStr.substring(salaryStr.length() - 1, salaryStr.length());

        if (!"月".equals(date) && !"年".equals(date)) {
            salaryStr = salaryStr.substring(0, salaryStr.length() - 2);
            salary[0] = salary[1] = str2Num(salaryStr, 365);
            return salary;
        }

        String unit = salaryStr.substring(salaryStr.length() - 3, salaryStr.length() - 2);
        String[] salarys = salaryStr.substring(0, salaryStr.length() - 3).split("-");

        salary[0] = mathSalary(date, unit, salarys[0]);
        salary[1] = mathSalary(date, unit, salarys[1]);
        return salary;
    }
    
    private static Integer mathSalary(String date, String unit, String salaryStr) {
        Integer salary = 0;
        
        if ("万".equals(unit)) {
            salary = str2Num(salaryStr, 10000);
        } else {
            salary = str2Num(salaryStr, 1000);
        }
        
        if ("月".equals(date)) {
            salary = str2Num(salary.toString(), 12);
        }
        return salary;
    }


    private static int str2Num(String salaryStr, int num) {
        try {
            Number result = Float.parseFloat(salaryStr) * num;
            return result.intValue();
        } catch (Exception e) {
        }
        return 0;
    }
}

编写爬虫

JobProcessor.java

package job.task;

import job.domain.JobInfo;
import org.jsoup.Jsoup;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;
import us.codecraft.webmagic.Page;
import us.codecraft.webmagic.Site;
import us.codecraft.webmagic.Spider;
import us.codecraft.webmagic.processor.PageProcessor;
import us.codecraft.webmagic.scheduler.BloomFilterDuplicateRemover;
import us.codecraft.webmagic.scheduler.QueueScheduler;
import us.codecraft.webmagic.selector.Html;
import us.codecraft.webmagic.selector.Selectable;

import java.util.List;

@Component
public class JobProcessor implements PageProcessor {
    private int yema=2;
    private String url = "https://search.51job.com/list/000000,000000,0000,00,9,99,java,2,1.html?lang=c&postchannel=0000&workyear=99&cotype=99°reefrom=99&jobterm=99&companysize=99&ord_field=0&dibiaoid=0&line=&welfare=";

    @Override
    public void process(Page page) {
        //解析页面，获取招聘信息详情的url地址
        List<Selectable> list = page.getHtml().regex("\"job_href\":\"(.*?)\"").nodes();
        //判断获取到的集合是否为空
        if (list.size() == 0) {
            // 如果为空，表示这是招聘详情页,解析页面，获取招聘详情信息，保存数据
            this.saveJobInfo(page);
        } else {
            //如果不为空，表示这是列表页,解析出详情页的url地址，放到任务队列中
            for (Selectable selectable : list) {
                //获取url地址
                String jobInfoUrl = selectable.toString();
                jobInfoUrl = jobInfoUrl.replace("\\","");
                //把获取到的url地址放到任务队列中
                page.addTargetRequest(jobInfoUrl);
            }
            if (this.yema<100)
            {
                //下一页的url
                String next_url = "https://search.51job.com/list/000000,000000,0000,00,9,99,java,2,"+this.yema+".html?lang=c&postchannel=0000&workyear=99&cotype=99°reefrom=99&jobterm=99&companysize=99&ord_field=0&dibiaoid=0&line=&welfare=";
                //把url放到任务队列中
                page.addTargetRequest(next_url);
                this.yema = this.yema+1;
            }
        }
    }
    //解析页面，获取招聘详情信息，保存数据
    private void saveJobInfo(Page page) {
        //创建招聘详情对象
        JobInfo jobInfo  = new JobInfo();
        //解析页面
        Html html = page.getHtml();
        //获取数据，封装到对象中
        jobInfo.setCompanyName(html.css("p.cname > a","text").toString());
        String tmp = html.css("p.ltype","title").toString();
        String[] strings = tmp.split("  |  ");
        jobInfo.setCompanyAddr(strings[0]);
        jobInfo.setCompanyInfo(Jsoup.parse(html.css("div.tmsg").toString()).text());
        jobInfo.setJobName(html.css("div.in > div.cn > h1","text").toString());
        jobInfo.setJobAddr(html.css("div.bmsg > p.fp","text").toString());
        jobInfo.setJobInfo(Jsoup.parse(html.css("div.job_msg").toString()).text());
        jobInfo.setUrl(page.getUrl().toString());
        //获取薪资
        Integer[] salary = MathSalary.getSalary(html.css("div.cn strong", "text").toString());
        jobInfo.setSalaryMin(salary[0]);
        jobInfo.setSalaryMax(salary[1]);
        //获取发布时间
        String time = html.css("p.ltype","title").regex("\\d\\d-\\d\\d发布").toString();
        jobInfo.setTime(time.substring(0,time.length()-2));
        //把结果保存起来
        page.putField("jobInfo",jobInfo);
    }


    private Site site = Site.me()
            .setCharset("gbk")//设置编码
            .setTimeOut(10 * 1000)//设置超时时间
            .setRetrySleepTime(3000)//设置重试的间隔时间
            .setRetryTimes(3);//设置重试的次数

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

    @Autowired
    private SpringDataPipeline springDataPipeline;

    //initialDelay当任务启动后，等等多久执行方法
    //fixedDelay每个多久执行方法
    @Scheduled(initialDelay = 1000, fixedDelay = 1000 * 1000)
    public void process() {
        Spider.create(new JobProcessor())
                .addUrl(url)
                .setScheduler(new QueueScheduler().setDuplicateRemover(new BloomFilterDuplicateRemover(100000)))
                .thread(10)
                .addPipeline(this.springDataPipeline)
                .run();
    }
}

运行引导类即可爬取数据。
爬取的部分数据如下：

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