Java之网络爬虫WebCollector+selenium+phantomjs(二)

上一篇做小例子的时候，在获取页面上价格的时候发现，获取不到，查了下说是webcollector需要结合selenium与phantomjs来获取js生成的动态。下面就做个例子来学习。

准备材料在上一篇已经准备完毕，我是在windows系统上进行的测试，所以phantomjs运行环境下载phantomjs-windows下载即可，下载后解压到某个文件夹即可(可以把解压路径添加到环境变量里，如果没有加到环境变量那么在启动的时候需要加上路径)。selenium与phantomjs的jar包都在上一篇的pom文件里。

下面贴出代码:

PageUtisl.java

/* * Copyright (C) 2015 zhao * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA. */package com.zhao.crawler.util;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import org.openqa.selenium.WebDriver;import org.openqa.selenium.htmlunit.HtmlUnitDriver;import org.openqa.selenium.phantomjs.PhantomJSDriver;import com.gargoylesoftware.htmlunit.BrowserVersion;import cn.edu.hfut.dmic.webcollector.model.Page;/** *  *  * @author <a href="[e-mail]">zhao</> * @date 2015-10-22 */public class PageUtils {/** * 获取webcollector 自带 htmlUnitDriver实例(模拟默认浏览器) * * @param page * @return */public static HtmlUnitDriver getDriver(Page page) {HtmlUnitDriver driver = new HtmlUnitDriver();driver.setJavascriptEnabled(true);driver.get(page.getUrl());return driver;}/** * 获取webcollector 自带htmlUnitDriver实例  * * @param page * @param browserVersion 模拟浏览器 * @return */public static HtmlUnitDriver getDriver(Page page,BrowserVersion browserVersion) {HtmlUnitDriver driver = new HtmlUnitDriver(browserVersion);driver.setJavascriptEnabled(true);driver.get(page.getUrl());return driver;}/** * 获取PhantomJsDriver(可以爬取js动态生成的html) * * @param page * @return */public static WebDriver getWebDriver(Page page) {//    WebDriver driver = new HtmlUnitDriver(true);    //    System.setProperty("webdriver.chrome.driver", "D:\\Installs\\Develop\\crawling\\chromedriver.exe");//    WebDriver driver = new ChromeDriver();        System.setProperty("phantomjs.binary.path", "D:/Program Files/phantomjs-2.0.0-windows/bin/phantomjs.exe");    WebDriver driver = new PhantomJSDriver();    driver.get(page.getUrl());    //    JavascriptExecutor js = (JavascriptExecutor) driver;//    js.executeScript("function(){}");    return driver;    }/** * 直接调用原生phantomJS(即不通过selenium) * * @param page * @return */public static String getPhantomJSDriver(Page page) {    Runtime rt = Runtime.getRuntime();    Process process = null;    try {process = rt.exec("D:/Program Files/phantomjs-2.0.0-windows/bin/phantomjs.exe" + "D:/MyEclipseWorkSpace/WebCollectorDemo/src/main/resources/parser.js " +page.getUrl().trim());InputStream in = process.getInputStream();InputStreamReader reader = new InputStreamReader(in, "UTF-8");BufferedReader br = new BufferedReader(reader);StringBuffer sbf = new StringBuffer();String tmp = "";while((tmp = br.readLine())!=null){                    sbf.append(tmp);                }return sbf.toString();} catch (IOException e) {e.printStackTrace();}        return null;    }}

上面代码是获取html页面的driver方法(框架自带的HtmlUnitDriver和第三方phantomjs driver)。

DemoJsCrawler.java

/* * Copyright (C) 2015 zhao * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA. */package com.zhao.crawler.demo;import java.util.List;import org.jsoup.nodes.Document;import org.jsoup.nodes.Element;import org.openqa.selenium.By;import org.openqa.selenium.WebDriver;import org.openqa.selenium.WebElement;import org.openqa.selenium.htmlunit.HtmlUnitDriver;import com.gargoylesoftware.htmlunit.BrowserVersion;import com.zhao.crawler.util.PageUtils;import cn.edu.hfut.dmic.webcollector.crawler.DeepCrawler;import cn.edu.hfut.dmic.webcollector.model.Links;import cn.edu.hfut.dmic.webcollector.model.Page;/** * * * @author <a href="[e-mail]">zhao</> * @date 2015-10-22 */public class DemoJSCrawler extends DeepCrawler {public DemoJSCrawler(String crawlPath) {        super(crawlPath);    }    @Override    public Links visitAndGetNextLinks(Page page) {       //HtmlUnitDriver//    handleByHtmlUnitDriver(page);        //PhantomJsDriver    handleByPhantomJsDriver(page);        return null;    }        /**     * webcollector自带获取html driver测试     *     * @param page     */    protected void handleByHtmlUnitDriver(Page page){     /*HtmlUnitDriver可以抽取JS生成的数据*/      HtmlUnitDriver driver=PageUtils.getDriver(page,BrowserVersion.CHROME);      /*HtmlUnitDriver也可以像Jsoup一样用CSS SELECTOR抽取数据        关于HtmlUnitDriver的文档请查阅selenium相关文档*/      print(driver);    }        /**     * phantomjs driver测试     *     * @param page     */    protected void handleByPhantomJsDriver(Page page){     WebDriver driver=PageUtils.getWebDriver(page);     print(driver);     driver.quit();    }        protected void print(WebDriver driver){    List<WebElement> divInfos = driver.findElements(By.cssSelector("li.gl-item"));        for(WebElement divInfo:divInfos){        WebElement price=divInfo.findElement(By.className("J_price"));            System.out.println(price+":"+price.getText());        }    }    public static void main(String[] args) throws Exception{        DemoJSCrawler crawler=new DemoJSCrawler("D:/test/crawler/jd/");        crawler.addSeed("http://list.jd.com/list.html?cat=1319,1523,7052&page=1&go=0&JL=6_0_0");        crawler.start(1);    }}

这个类继承了DeepCrawler,里面主要有三个方法:

print()方法:打印获取的价格信息，格式为：价格所在元素：价格。

我打算捕获商品列表页面上的价格，用浏览器审查元素如下图所示

:
商品位于列表标签li class为gl-item的元素里面，再深入到里面价格在class 为J_price的strong标签里面。按照这个逻辑，我们先获取列表元素，然后再定位到价格标签，打印的时候格式为：价格所在标签:价格。

方法中的price.getText()是获取标签中间或子标签的文本内容(会自动过滤掉标签而获取其中的文本内容)。具体请查看selenium-api-2.12.chm

handleByHtmlUnitDriver():这个方法是用自带的driver获取页面。

下面运行程序，打印结果如下：

只打印了定位的标签，但是没有打印价格(通过查看 页面的js文件发现，京东的价格是js动态加载到页面上的)。证明webcollector 自带的html dirver对处理js动态生成的html页面并不友好。所以这时候就需要另外两个框架selenium与phantomjs配合抓取js动态生成的html页面。

handleByPhantomJsDriver()方法为通过PhantomJsDriver来获取html页面，运行结果如下所示:

通过日志看到成功获取到价格。下一篇将会做一个爬取京东商品列表信息的小例子，并且提供源码下载。上一篇提供各种资源下载及环境搭建。