1. 爬虫框架webmagic

WebMagic是一个简单灵活的爬虫框架。基于WebMagic，你可以快速开发出一个高效、易维护的爬虫。

1.1 官网地址

官网文档写的比较清楚，建议大家直接阅读官方文档，也可以阅读下面的内容。地址如下：

官网：http://webmagic.io

中文文档地址: http://webmagic.io/docs/zh/

English: http://webmagic.io/docs/en

2. webmagic与spring boot框架集成

spring boot与webmagic的结合主要有三个模块，分别为爬取模块Processor,入库模块Pipeline，向数据库存入爬取数据，和定时任务模块Scheduled,复制定时爬取网站数据。

2.1 maven添加

<dependency>     <groupId>us.codecraft</groupId>    <artifactId>webmagic-core</artifactId>    <version>0.5.3</version></dependency><dependency>    <groupId>us.codecraft</groupId>    <artifactId>webmagic-extension</artifactId>    <version>0.5.3</version></dependency>

2.2 爬取模块Processor

爬取简书首页Processor，分析简书首页的页面数据，获取响应的简书链接和标题，放入wegmagic的Page中，到入库模块取出添加到数据库。代码如下：

package com.shang.spray.common.processor;import com.shang.spray.entity.News;import com.shang.spray.entity.Sources;import com.shang.spray.pipeline.NewsPipeline;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.selector.Selectable;import java.util.List;/** * info:简书首页爬虫 * Created by shang on 16/9/9. */public class JianShuProcessor implements PageProcessor {    private Site site = Site.me()            .setDomain("jianshu.com")            .setSleepTime(100)            .setUserAgent("Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36");    ;    public static final String list = "http://www.jianshu.com";    @Override    public void process(Page page) {        if (page.getUrl().regex(list).match()) {            List<Selectable> list=page.getHtml().xpath("//ul[@class=‘article-list thumbnails‘]/li").nodes();            for (Selectable s : list) {                String title=s.xpath("//div/h4/a/text()").toString();                String link=s.xpath("//div/h4").links().toString();                News news=new News();                news.setTitle(title);                news.setInfo(title);                news.setLink(link);                news.setSources(new Sources(5));                page.putField("news"+title, news);            }        }    }    @Override    public Site getSite() {        return site;    }    public static void main(String[] args) {        Spider spider=Spider.create(new JianShuProcessor());        spider.addUrl("http://www.jianshu.com");        spider.addPipeline(new NewsPipeline());        spider.thread(5);        spider.setExitWhenComplete(true);        spider.start();    }}

2.3 入库模块Pipeline

入库模块结合spring boot的Repository模块一起组合成入库方法，继承webmagic的Pipeline，然后实现方法，在process方法中获取爬虫模块的数据，然后调用spring boot的save方法。代码如下：

package com.shang.spray.pipeline;import com.shang.spray.entity.News;import com.shang.spray.entity.Sources;import com.shang.spray.repository.NewsRepository;import org.apache.commons.lang3.StringUtils;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.data.jpa.domain.Specification;import org.springframework.stereotype.Repository;import us.codecraft.webmagic.ResultItems;import us.codecraft.webmagic.Task;import us.codecraft.webmagic.pipeline.Pipeline;import javax.persistence.criteria.CriteriaBuilder;import javax.persistence.criteria.CriteriaQuery;import javax.persistence.criteria.Predicate;import javax.persistence.criteria.Root;import java.util.ArrayList;import java.util.Date;import java.util.List;import java.util.Map;/** * info:新闻 * Created by shang on 16/8/22. */@Repositorypublic class NewsPipeline implements Pipeline {    @Autowired    protected NewsRepository newsRepository;    @Override    public void process(ResultItems resultItems, Task task) {        for (Map.Entry<String, Object> entry : resultItems.getAll().entrySet()) {            if (entry.getKey().contains("news")) {                News news=(News) entry.getValue();                Specification<News> specification=new Specification<News>() {                    @Override                    public Predicate toPredicate(Root<News> root, CriteriaQuery<?> criteriaQuery, CriteriaBuilder criteriaBuilder) {                        return criteriaBuilder.and(criteriaBuilder.equal(root.get("link"),news.getLink()));                    }                };                if (newsRepository.findOne(specification) == null) {//检查链接是否已存在                    news.setAuthor("水花");                    news.setTypeId(1);                    news.setSort(1);                    news.setStatus(1);                    news.setExplicitLink(true);                    news.setCreateDate(new Date());                    news.setModifyDate(new Date());                    newsRepository.save(news);                }            }        }    }}

2.4 定时任务模块Scheduled

使用spring boot自带的定时任务注解@Scheduled(cron = "0 0 0/2 * * ? "),每天从0天开始，每两个小时执行一次爬取任务，在定时任务里调取webmagic的爬取模块Processor。代码如下：

package com.shang.spray.common.scheduled;import com.shang.spray.common.processor.DevelopersProcessor;import com.shang.spray.common.processor.JianShuProcessor;import com.shang.spray.common.processor.ZhiHuProcessor;import com.shang.spray.entity.Config;import com.shang.spray.pipeline.NewsPipeline;import com.shang.spray.service.ConfigService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.data.jpa.domain.Specification;import org.springframework.scheduling.annotation.Scheduled;import org.springframework.stereotype.Component;import us.codecraft.webmagic.Spider;import javax.persistence.criteria.CriteriaBuilder;import javax.persistence.criteria.CriteriaQuery;import javax.persistence.criteria.Predicate;import javax.persistence.criteria.Root;/** * info:新闻定时任务 * Created by shang on 16/8/22. */@Componentpublic class NewsScheduled {    @Autowired    private NewsPipeline newsPipeline;    /**     * 简书     */    @Scheduled(cron = "0 0 0/2 * * ? ")//从0点开始,每2个小时执行一次    public void jianShuScheduled() {        System.out.println("----开始执行简书定时任务");        Spider spider = Spider.create(new JianShuProcessor());        spider.addUrl("http://www.jianshu.com");        spider.addPipeline(newsPipeline);        spider.thread(5);        spider.setExitWhenComplete(true);        spider.start();        spider.stop();    }}

2.5 spring boot启用定时任务

在spring boot的Application里启用定时任务注解，@EnableScheduling。代码如下：

package com.shang.spray;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.EnableAutoConfiguration;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.boot.builder.SpringApplicationBuilder;import org.springframework.boot.context.web.SpringBootServletInitializer;import org.springframework.context.annotation.ComponentScan;import org.springframework.context.annotation.Configuration;import org.springframework.scheduling.annotation.EnableScheduling;/** * info: * Created by shang on 16/7/8. */@Configuration@EnableAutoConfiguration@ComponentScan@SpringBootApplication@EnableSchedulingpublic class SprayApplication extends SpringBootServletInitializer{    @Override    protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {        return application.sources(SprayApplication.class);    }    public static void main(String[] args) throws Exception {        SpringApplication.run(SprayApplication.class, args);    }}

3. 结束语

使用webmagic是我在水花一现项目中爬取网站数据时使用的的爬虫框架，在综合比较的其他几个爬虫框架后，选择了这个框架，这个框架比较简单易学，且功能强大，我这里只使用了基本的功能，还有许多强大的功能都没有使用。有兴趣的可以去看看官方文档！