Java 爬虫 Java爬虫范例之使用Htmlunit爬取学校教务网课程表信息
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使用WebClient和htmlunit实现简易爬虫
import com.gargoylesoftware.htmlunit.WebClient;
提供了public
P getPage(final String url)方法获得HtmlPage。
import com.gargoylesoftware.htmlunit.html.*;
包含了HtmlPage、HtmlForm、HtmlTextInput、HtmlPasswordInput、HtmlElement、DomElement等元素。
构造webclient对象
WebClient webClient= new WebClient();
无参默认是BrowserVersion.BEST_SUPPORTED,有参构造支持5种浏览器:
BrowserVersion.CHROME
BrowserVersion.EDGE
BrowserVersion.FIREFOX
BrowserVersion.FIREFOX_78
BrowserVersion.INTERNET_EXPLOER
使用webclient.getPage(String url)获得页面:
try { page = webClient.getPage(url); } catch (IOException e) { e.printStackTrace(); }
利用webClient.getPage(url);方法,将其封装成一个getHtmlPage静态方法
private static class innerWebClient{ private static final WebClient webClient = new WebClient(); } public static HtmlPage getHtmlPage(String url){ //调用此方法时加载WebClient WebClient webClient = innerWebClient.webClient; webClient.getOptions().setCssEnabled(false); //配置webClient webClient.getOptions().setCssEnabled(false); //设置CSS是否生效 webClient.getOptions().setJavaScriptEnabled(true); //设置JS是否生效 webClient.setAjaxController(new NicelyResynchronizingAjaxController()); //设置AJAX请求 webClient.getOptions().setThrowExceptionOnFailingStatusCode(false); //设置是否抛出异常码 webClient.getOptions().setThrowExceptionOnScriptError(false); //设置是否抛出脚本错误 webClient.waitForBackgroundJavaScript(3*1000); //设置等待JS毫秒数 webClient.getCookieManager().setCookiesEnabled(true); //设置是否支持Cookie HtmlPage page = null; try { page = webClient.getPage(url); } catch (IOException e) { e.printStackTrace(); } return page; }
在教务官网学期课表页,拿到对应标签的ID
登录教务官网页面:
静态解析课程信息方法:
//获取周次集合 public static ArrayList<Integer> getWeekCount(String weekAndSection){ ArrayList<Integer> weekList = new ArrayList<>(); int index = weekAndSection.indexOf("(周)"); if(index == -1){ return new ArrayList<>(); } String subWeek = weekAndSection.substring(0, index); //1-3,5,15,18 String[] weekArr = new String[10]; int idx = subWeek.indexOf(","); //1或3 int num = 0,n = 0; while (subWeek.contains(",")){ weekArr[num] = subWeek.substring(0,idx); //第一个逗号前面的内容,给数组 subWeek = subWeek.substring(idx+1); //剩余内容 n = subWeek.indexOf(","); idx = n; num++; } weekArr[num] = subWeek; for (String s : weekArr) { if(s!=null && !s.equals("")){ if(s.contains("-")){ int ix = s.indexOf("-"); int begin = Integer.parseInt(s.substring(0,ix)); int end = Integer.parseInt(s.substring(ix+1)); for (int i = begin; i <= end; i++) { weekList.add(i); } }else{ weekList.add(Integer.parseInt(s)); } } } return weekList; }
//获取节次集合 public static ArrayList<Integer> getSectionCount(String weekAndSection){ int begin = weekAndSection.indexOf("[") + 1; int end = weekAndSection.indexOf("节"); String section = weekAndSection.substring(begin, end); int len = section.length(); String first = section.substring(0,2); String last = section.substring(len-2,len); ArrayList<Integer> sectionList = new ArrayList<>(); int firstInt = Integer.parseInt(first); int lastInt = Integer.parseInt(last); for (int i = firstInt; i <= lastInt; i++) { sectionList.add(i); } return sectionList; }
开始解析课程信息
DomElement[][] domElements = new DomElement[7][6]; //7天,6个节次部分 String key = ""; //星期一~星期日:1-2~7-2 for (int i = 0;i < 7;i++){ //星期一到星期日 for (int j = 0;j <= 5;j++){ //sectionIds[0]到sectionIds[5] if(j == 2){ //由于第5节为空,略过 continue; } key = sectionIds[j] + "-" + (i+1) + "-2"; if(page3.getElementById(key) == null){ throw new NullPointerException("Key过期了!"); }else{ domElements[i][j] = page3.getElementById(key); } String course = domElements[i][j].asText(); String temp[] = new String[10]; int num = 0; int index; for (int g = 0; course.contains("---------------------"); g = g + index) { index = course.indexOf("---------------------"); temp[num] = course.substring(0,index); course = course.substring(index+21); num++; } temp[num] = course; String[] courseInfo = new String[4]; for (int k = 0;k < temp.length;k++) { if(temp[k] == null || temp[k].equals("") || temp[k].equals(" ")){ continue; } if(temp[k].indexOf("\n") == 1){ temp[k] = temp[k].substring(2); } ArrayList<Integer> weekList; ArrayList<Integer> sectionList; if(temp[k].contains("网络课")){ temp[k] = temp[k].substring(0,temp[k].indexOf("\n")); courseInfo[0] = temp[k]; weekList = null; sectionList = null; }else{ int idx,cnum = 0; for(int h = 0; temp[k].contains("\n") && cnum <= 3;h = h+idx){ idx = temp[k].indexOf("\n"); courseInfo[cnum] = temp[k].substring(0,idx); temp[k] = temp[k].substring(idx+1); cnum++; } weekList = getWeekCount(courseInfo[2]); sectionList = getSectionCount(courseInfo[2]); } System.out.println("课程名===" + courseInfo[0]); System.out.println("教师名===" + courseInfo[1]); System.out.println("周次===" + weekList); System.out.println("节次===" + sectionList); System.out.println("地点===" + courseInfo[3]); System.out.println("星期" + (i+1)); } } }
输出效果:
基于Uni-App实现的课程表小程序:
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