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听到“爬虫”，是不是第一时间想到Python/php ？ 多少想玩爬虫的Java学习者就因为语言不通而止步。Java是真的不能做爬虫吗？
当然不是。
只不过python的3行代码能解决的问题，而Java要30行。
这里推荐大家一个大牛做的java爬虫框架 【WebMagic】
文档简单易懂！java爬虫开发的福利啊！
一起来动手做一个小应用吧！
爬虫思想有3步
1. 抽取目标链接
2. 抽取需要的信息
3. 处理数据
一、 抽取目标链接 （确定入口地址，这里的入口是https://www.zhihu.com/search?type=people&q=java）
接下来查看html结构，确定待爬取的目标链接。（这里我的目标链接是【前10个用户的详细信息页面的url】）
二、抽取需要的信息（webmagic提供了3种方式，xpath，css选择，正则表达式。具体可以查看下[WebMagic文档](http://webmagic.io/docs/zh/)）
确定好【目标的信息】，如下图。
创建对应的实体对象
package entity;
/**
* 知乎用户信息
* @author antgan
*
*/
public class ZhihuUser {
private String key;//keyword
private String name;//用户名
private String identity;//身份
private String location;//所在地
private String profession;//行业
private int sex;//性别
private String school;//学校
private String major;//专业
private String recommend;//个人简介
private String picUrl;//头像url
private int agree;//赞同
private int thanks;//感谢
private int ask;//提问数
private int answer;//回答数
private int article;//文章数
private int collection;//收藏数
public String getKey() {
return key;
}
public void setKey(String key) {
this.key = key;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getIdentity() {
return identity;
}
public void setIdentity(String identity) {
this.identity = identity;
}
public String getLocation() {
return location;
}
public void setLocation(String location) {
this.location = location;
}
public String getProfession() {
return profession;
}
public void setProfession(String profession) {
this.profession = profession;
}
public int getSex() {
return sex;
}
public void setSex(int sex) {
this.sex = sex;
}
public String getSchool() {
return school;
}
public void setSchool(String school) {
this.school = school;
}
public String getMajor() {
return major;
}
public void setMajor(String major) {
this.major = major;
}
public String getRecommend() {
return recommend;
}
public void setRecommend(String recommend) {
this.recommend = recommend;
}
public String getPicUrl() {
return picUrl;
}
public void setPicUrl(String picUrl) {
this.picUrl = picUrl;
}
public int getAgree() {
return agree;
}
public void setAgree(int agree) {
this.agree = agree;
}
public int getThanks() {
return thanks;
}
public void setThanks(int thanks) {
this.thanks = thanks;
}
public int getAsk() {
return ask;
}
public void setAsk(int ask) {
this.ask = ask;
}
public int getAnswer() {
return answer;
}
public void setAnswer(int answer) {
this.answer = answer;
}
public int getArticle() {
return article;
}
public void setArticle(int article) {
this.article = article;
}
public int getCollection() {
return collection;
}
public void setCollection(int collection) {
this.collection = collection;
}
@Override
public String toString() {
return "ZhihuUser [name=" + name + ", identity=" + identity + ", location=" + location + ", profession="
+ profession + ", sex=" + sex + ", school=" + school + ", major=" + major + ", recommend=" + recommend
+ ", picUrl=" + picUrl + ", agree=" + agree + ", thanks=" + thanks + ", ask=" + ask + ", answer="
+ answer + ", article=" + article + ", collection=" + collection + "]";
}
}
编写PageProcessor（Processor中的process方法是webmagic的核心，负责抽取目标url的逻辑）
package repo;
import dao.ZhihuDao;
import dao.impl.ZhihuDaoImpl;
import entity.ZhihuUser;
import us.codecraft.webmagic.Page;
import us.codecraft.webmagic.Site;
import us.codecraft.webmagic.Spider;
import us.codecraft.webmagic.processor.PageProcessor;
/**
* 知乎用户小爬虫<br>
* 输入搜索用户关键词(keyword)，并把搜出来的用户信息爬出来<br>
* @date 2016-5-3
* @website ghb.soecode.com
* @csdn blog.csdn.net/antgan
* @author antgan
*
*/
public class ZhiHuUserPageProcessor 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(10).setSleepTime(1000);
//用户数量
private static int num = 0;
//搜索关键词
private static String keyword = "JAVA";
//数据库持久化对象，用于将用户信息存入数据库
private ZhihuDao zhihuDao = new ZhihuDaoImpl();
/**
* process 方法是webmagic爬虫的核心<br>
* 编写抽取【待爬取目标链接】的逻辑代码在html中。
*/
@Override
public void process(Page page) {
//1. 如果是用户列表页面 【入口页面】，将所有用户的详细页面的url放入target集合中。
if(page.getUrl().regex("https://www\\.zhihu\\.com/search\\?type=people&q=[\\s\\S]+").match()){
page.addTargetRequests(page.getHtml().xpath("//ul[@class=‘list users‘]/li/div/div[@class=‘body‘]/div[@class=‘line‘]").links().all());
}
//2. 如果是用户详细页面
else{
num++;//用户数++
/*实例化ZhihuUser，方便持久化存储。*/
ZhihuUser user = new ZhihuUser();
/*从下载到的用户详细页面中抽取想要的信息，这里使用xpath居多*/
/*为了方便理解，抽取到的信息先用变量存储，下面再赋值给对象*/
String name = page.getHtml().xpath("//div[@class=‘title-section ellipsis‘]/span[@class=‘name‘]/text()").get();
String identity = page.getHtml().xpath("//div[@class=‘title-section ellipsis‘]/span[@class=‘bio‘]/@title").get();
String location = page.getHtml().xpath("//div[@class=‘item editable-group‘]/span[@class=‘info-wrap‘]/span[@class=‘location item‘]/@title").get();
String profession = page.getHtml().xpath("//div[@class=‘item editable-group‘]/span[@class=‘info-wrap‘]/span[@class=‘business item‘]/@title").get();
boolean isMale = page.getHtml().xpath("//span[@class=‘item gender‘]/i[@class=‘icon icon-profile-male‘]").match();
boolean isFemale = page.getHtml().xpath("//span[@class=‘item gender‘]/i[@class=‘icon icon-profile-female‘]").match();
int sex = -1;
/*因为知乎有一部分人不设置性别 或者 不显示性别。所以需要判断一下。*/
if(isMale&&!isFemale) sex=1;//1代表男性
else if(!isMale&&isFemale) sex=0;//0代表女性
else sex=2;//2代表未知
String school = page.getHtml().xpath("//span[@class=‘education item‘]/@title").get();
String major = page.getHtml().xpath("//span[@class=‘education-extra item‘]/@title").get();
String recommend = page.getHtml().xpath("//span[@class=‘fold-item‘]/span[@class=‘content‘]/@title").get();
String picUrl = page.getHtml().xpath("//div[@class=‘body clearfix‘]/img[@class=‘Avatar Avatar--l‘]/@src").get();
int agree = Integer.parseInt(page.getHtml().xpath("//span[@class=‘zm-profile-header-user-agree‘]/strong/text()").get());
int thanks = Integer.parseInt(page.getHtml().xpath("//span[@class=‘zm-profile-header-user-thanks‘]/strong/text()").get());
int ask = Integer.parseInt(page.getHtml().xpath("//div[@class=‘profile-navbar clearfix‘]/a[2]/span[@class=‘num‘]/text()").get());
int answer = Integer.parseInt(page.getHtml().xpath("//div[@class=‘profile-navbar clearfix‘]/a[3]/span[@class=‘num‘]/text()").get());
int article = Integer.parseInt(page.getHtml().xpath("//div[@class=‘profile-navbar clearfix‘]/a[4]/span[@class=‘num‘]/text()").get());
int collection = Integer.parseInt(page.getHtml().xpath("//div[@class=‘profile-navbar clearfix‘]/a[5]/span[@class=‘num‘]/text()").get());
//对象赋值
user.setKey(keyword);
user.setName(name);
user.setIdentity(identity);
user.setLocation(location);
user.setProfession(profession);
user.setSex(sex);
user.setSchool(school);
user.setMajor(major);
user.setRecommend(recommend);
user.setPicUrl(picUrl);
user.setAgree(agree);
user.setThanks(thanks);
user.setAsk(ask);
user.setAnswer(answer);
user.setArticle(article);
user.setCollection(collection);
System.out.println("num:"+num +" " + user.toString());//输出对象
zhihuDao.saveUser(user);//保存用户信息到数据库
}
}
@Override
public Site getSite() {
return this.site;
}
public static void main(String[] args) {
long startTime ,endTime;
System.out.println("========知乎用户信息小爬虫【启动】喽！=========");
startTime = new Date().getTime();
//入口为：【https://www.zhihu.com/search?type=people&q=xxx 】，其中xxx 是搜索关键词
Spider.create(new ZhiHuUserPageProcessor()).addUrl("https://www.zhihu.com/search?type=people&q="+keyword).thread(5).run();
endTime = new Date().getTime();
System.out.println("========知乎用户信息小爬虫【结束】喽！=========");
System.out.println("一共爬到"+num+"个用户信息！用时为："+(endTime-startTime)/1000+"s");
}
Dao层接口
package dao;
import entity.ZhihuUser;
/**
* 知乎 数据持久化 接口
* @author 甘海彬
*
*/
public interface ZhihuDao {
/**
* 保存用户信息
* @param user
* @return
*/
public int saveUser(ZhihuUser user);
}
Dao实现类
package dao.impl;
import java.util.ArrayList;
import java.util.List;
import dao.ZhihuDao;
import entity.ZhihuUser;
import util.DBHelper;
/**
* 知乎 数据库持久化接口 实现
* @author 甘海彬
*
*/
public class ZhihuDaoImpl implements ZhihuDao{
@Override
public int saveUser(ZhihuUser user) {
DBHelper dbhelper = new DBHelper();
StringBuffer sql = new StringBuffer();
sql.append("INSERT INTO spider_zhihu_user ( `key`,`name`,identity,location,profession,sex,school,major,recommend,picUrl,agree,thanks,ask,answer,article,collection)")
//`key`,`name`,identity,location,profession,sex,school,major,recommend,picUrl,agree,thanks,ask,answer,article,collection
.append("VALUES (? , ? , ? , ? , ? , ? , ? , ? , ? , ? , ? , ? , ? , ? , ? , ? ) ");
//设置 sql values 的值
List<String> sqlValues = new ArrayList<>();
sqlValues.add(user.getKey());
sqlValues.add(user.getName());
sqlValues.add(user.getIdentity());
sqlValues.add(user.getLocation());
sqlValues.add(user.getProfession());
sqlValues.add(""+user.getSex());
sqlValues.add(user.getSchool());
sqlValues.add(user.getMajor());
sqlValues.add(user.getRecommend());
sqlValues.add(user.getPicUrl());
sqlValues.add(""+user.getAgree());
sqlValues.add(""+user.getThanks());
sqlValues.add(""+user.getAsk());
sqlValues.add(""+user.getAnswer());
sqlValues.add(""+user.getArticle());
sqlValues.add(""+user.getCollection());
int result = dbhelper.executeUpdate(sql.toString(), sqlValues);
return result;
}
}
这里我封装了个DbHelpler类，方便进行持久化操作，使用单例模式，并线程同步。
package util;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;
/**
* Mysql && SQL Server DBHelper
* @author antgan
*/
public class DBHelper {
public static final String driver_class = "com.mysql.jdbc.Driver";
public static final String driver_url = "jdbc:mysql://127.0.0.1/antgan?useunicode=true&characterEncoding=utf8";
public static final String user = "root";
public static final String password = "antgan";
private static Connection conn = null;
private PreparedStatement pst = null;
private ResultSet rst = null;
/**
* Connection
*/
public DBHelper() {
try {
conn = DBHelper.getConnInstance();
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 单例模式
* 线程同步
* @return
*/
private static synchronized Connection getConnInstance() {
if(conn == null){
try {
Class.forName(driver_class);
conn = DriverManager.getConnection(driver_url, user, password);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
System.out.println("连接数据库成功");
}
return conn;
}
/**
* close
*/
public void close() {
try {
if (conn != null) {
DBHelper.conn.close();
}
if (pst != null) {
this.pst.close();
}
if (rst != null) {
this.rst.close();
}
System.out.println("关闭数据库成功");
} catch (SQLException e) {
e.printStackTrace();
}
}
/**
* query
*
* @param sql
* @param sqlValues
* @return ResultSet
*/
public ResultSet executeQuery(String sql, List<String> sqlValues) {
try {
pst = conn.prepareStatement(sql);
if (sqlValues != null && sqlValues.size() > 0) {
setSqlValues(pst, sqlValues);
}
rst = pst.executeQuery();
} catch (SQLException e) {
e.printStackTrace();
}
return rst;
}
/**
* update
*
* @param sql
* @param sqlValues
* @return result
*/
public int executeUpdate(String sql, List<String> sqlValues) {
int result = -1;
try {
pst = conn.prepareStatement(sql);
if (sqlValues != null && sqlValues.size() > 0) {
setSqlValues(pst, sqlValues);
}
result = pst.executeUpdate();
} catch (SQLException e) {
e.printStackTrace();
}
return result;
}
/**
* sql set value
*
* @param pst
* @param sqlValues
*/
private void setSqlValues(PreparedStatement pst, List<String> sqlValues) {
for (int i = 0; i < sqlValues.size(); i++) {
try {
pst.setObject(i + 1, sqlValues.get(i));
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
噢！对了！表的创建sql也提供一下！
CREATE TABLE `spider_zhihu_user` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`key` varchar(30) DEFAULT NULL,
`name` varchar(30) DEFAULT NULL,
`identity` varchar(100) DEFAULT NULL,
`location` varchar(20) DEFAULT NULL,
`profession` varchar(30) DEFAULT NULL,
`sex` int(2) DEFAULT NULL,
`school` varchar(30) DEFAULT NULL,
`major` varchar(30) DEFAULT NULL,
`recommend` varchar(100) DEFAULT NULL,
`picUrl` varchar(255) DEFAULT NULL,
`agree` int(11) DEFAULT NULL,
`thanks` int(11) DEFAULT NULL,
`ask` int(11) DEFAULT NULL,
`answer` int(11) DEFAULT NULL,
`article` int(11) DEFAULT NULL,
`collection` int(11) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=104 DEFAULT CHARSET=utf8;
以上就是全部代码。
进行测试。
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原文地址：http://www.cnblogs.com/miercler/p/5599465.html
