webmagic使用一

1.配置，添加依赖

在IDEA中添加两个jar包：webmagic-core-{version}.jar和webmagic-extension-{version}.jar。

<dependency>
    <groupId>us.codecraft</groupId>
    <artifactId>webmagic-core</artifactId>
    <version>0.6.1</version>
</dependency>
<dependency>
    <groupId>us.codecraft</groupId>
    <artifactId>webmagic-extension</artifactId>
    <version>0.6.1</version>
</dependency>
添加依赖slf4j-log4j12
<dependency>
    <groupId>us.codecraft</groupId>
    <artifactId>webmagic-extension</artifactId>
    <version>0.6.1</version>
    <exclusions>
        <exclusion>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
        </exclusion>
    </exclusions>
</dependency>

2.实现第一个小爬虫

抓取GitHub

import us.codecraft.webmagic.Page;
import us.codecraft.webmagic.Site;
import us.codecraft.webmagic.Spider;
import us.codecraft.webmagic.processor.PageProcessor;
 
public class GitHub implements PageProcessor {
    // 抓取网站的相关配置，包括编码、抓取间隔、重试次数等
    private Site site = Site.me().setRetryTimes(3).setSleepTime(100);
    private static int count =0;
 
 
    public Site getSite() {
        return site;
    }
 
    public void process(Page page) {
        //判断链接是否符合http://www.cnblogs.com/任意个数字字母-/p/7个数字.html格式
        if(!page.getUrl().regex("http://www.cnblogs.com/[a-z 0-9 -]+/p/[0-9]{7}.html").match()){
            //加入满足条件的链接
            page.addTargetRequests(
                    page.getHtml().xpath("//*[@id="post_list"]/div/div[@class='post_item_body']/h3/a/@href").all());
        }else{
            //获取页面需要的内容
            System.out.println("抓取的内容："+
                    page.getHtml().xpath("//*[@id="Header1_HeaderTitle"]/text()").get()
            );
            count ++;
        }
    }
 
    public static void main(String[] args) {
        long startTime, endTime;
        System.out.println("开始爬取...");
        startTime = System.currentTimeMillis();
        Spider.create(new GitHub()).addUrl("https://www.cnblogs.com/").thread(5).run();
        endTime = System.currentTimeMillis();
        System.out.println("爬取结束，耗时约" + ((endTime - startTime) / 1000) + "秒，抓取了"+count+"条记录");
    }
 
}