最近在极客学院获得体验会员3个月，然后就去上面看了看，感觉课程讲的还不错。整好最近学习Android，然后去上面找点视频看看。发现只有使用RMB买的会员才能在上面下载视频。抱着试一试的态度，去看他的网页源码，不巧发现有视频地址链接。然后想起来jsoup提取网页元素挺方便的，没事干就写了一个demo。
jsoup 是一款java 的HTML解析器，可直接解析某个URL地址、HTML文本内容。它提供了一套非常省力的API，可通过DOM，CSS以及类似于jQuery的操作方法来取出和操作数据。 jsoup的主要功能如下： 1. 从一个URL，文件或字符串中解析HTML； 2. 使用DOM或CSS选择器来查找、取出数据； 3. 可操作HTML元素、属性、文本；jsoup的用法中文文档地址：http://www.open-open.com/jsoup/ 使用jsoup提取网页中指定的内容需要提前做好网页分析工作。我找到在极客学院一个课程的页面源码，很快找到了视频链接部分;如下图：<scource/> 标签中就是视频链接，通过这个链接我们可以通过迅雷下载。
<source src="http://cv3.jikexueyuan.com/201508081934/f8f3f9f8088f1ba0a6c75594448d96ab/course/1501-1600/1557/video/4278_b_h264_sd_960_540.mp4" type="video/mp4"></source>View Code
我们获取整个html源码，然后根据<scource/>对源码进行提取，很容易获取下载链接。
接着通过分析网页，我们可以得到一门课程所有视频信息。网页源码如下：
1 <dl class="lessonvideo-list"> 2 <dd class="playing"> 3 <h2> <span class="sm-icon "></span> <a href="http://www.jikexueyuan.com/course/1748_1.html?ss=1" jktag="&posGP=103001&posArea=0002&posOper=8005&posColumn=1.1">1.编写自己的自定义 View（上）</a> <span class="lesson-time">00:10:24</span> </h2> 4 <blockquote> 5 本课时主要讲解最简单的自定义 View，然后加入绘制元素（文字、图形等），并且可以像使用系统控件一样在布局中使用。 6 </blockquote> 7 </dd> 8 <dd> 9 <h2> <span class="sm-icon "></span> <a href="http://www.jikexueyuan.com/course/1748_2.html?ss=1" jktag="&posGP=103001&posArea=0002&posOper=8005&posColumn=2.2">2.编写自己的自定义 View（下）</a> <span class="lesson-time">00:12:05</span> </h2> 10 <blockquote>11 本课时主要讲解最简单的自定义 View，然后加入绘制元素（文字、图形等），并且可以像使用系统控件一样在布局中使用。12 </blockquote> 13 </dd> 14 <dd> 15 <h2> <span class="sm-icon "></span> <a href="http://www.jikexueyuan.com/course/1748_3.html?ss=1" jktag="&posGP=103001&posArea=0002&posOper=8005&posColumn=3.3">3.加入逻辑线程</a> <span class="lesson-time">00:20:34</span> </h2> 16 <blockquote>17 本课时需要让绘制的元素动起来，但是又不阻塞主线程，所以引入逻辑线程。在子线程更新 UI 是不被允许的，但是 View 提供了方法。让我们来看看吧。18 </blockquote> 19 </dd> 20 <dd> 21 <h2> <span class="sm-icon "></span> <a href="http://www.jikexueyuan.com/course/1748_4.html?ss=1" jktag="&posGP=103001&posArea=0002&posOper=8005&posColumn=4.4">4.提取和封装自定义 View</a> <span class="lesson-time">00:15:41</span> </h2> 22 <blockquote>23 本课时主要讲解在上个课程的基础上，进行提取代码来构造自定义 View 的基类，主要目的是：创建新的自定义 View 时，只需继承此类并只关心绘制和逻辑，其他工作由父类完成。这样既减少重复编码，也简化了逻辑。24 </blockquote> 25 </dd> 26 <dd> 27 <h2> <span class="sm-icon "></span> <a href="http://www.jikexueyuan.com/course/1748_5.html?ss=1" jktag="&posGP=103001&posArea=0002&posOper=8005&posColumn=5.5">5.在 xml 中定义样式来影响显示效果</a> <span class="lesson-time">00:14:05</span> </h2> 28 <blockquote>29 本课时主要讲解的是在 xml 中定义样式及其属性，怎么来影响自定义 View 中的显示效果的过程和步骤。30 </blockquote> 31 </dd> 32 </dl>View Code
通过 Elements results1 = doc.getElementsByClass("lessonvideo-list"); 我们可以获得视频列表。然后我们接着对从视频列表获取课程每节课视频地址使用jsoup遍历获取视频链接。
以上是主要思路，另外使用jsoup get方法获取网页Docment是是没有cooike状态的，有些视频需要Vip会员登录才能获取到视频播放地址。因此我们需要用httpclient来模拟用户登录状态。
一下是整个工程源码。
1 、课程course类，用于存储课程每一节课的课程名和课程url地址。
1 public class Course { 2 3 /** 4 * 链接的地址 5 */ 6 PRivate String linkHref; 7 /** 8 * 链接的标题 9 */10 private String linkText;11 12 public String getLinkHref() {13 return linkHref;14 }15 16 public void setLinkHref(String linkHref) {17 this.linkHref = linkHref;18 }19 20 public String getLinkText() {21 return linkText;22 }23 24 public void setLinkText(String linkText) {25 this.linkText = linkText;26 }27 28 @Override29 public String toString() {30 return "Video [linkHref=" + linkHref + ", linkText=" + linkText + "]";31 }32 33 }View Code2、HttpUtils类，用于模拟用户登录状态。 1 import java.io.IOException; 2 import java.io.InputStream; 3 import java.io.UnsupportedEncodingException; 4 5 import org.apache.http.Header; 6 import org.apache.http.HttpEntity; 7 import org.apache.http.HttpHeaders; 8 import org.apache.http.HttpResponse; 9 import org.apache.http.HttpStatus; 10 import org.apache.http.client.ClientProtocolException; 11 import org.apache.http.client.HttpClient; 12 import org.apache.http.client.methods.CloseableHttpResponse; 13 import org.apache.http.client.methods.HttpGet; 14 import org.apache.http.client.methods.HttpPost; 15 import org.apache.http.entity.StringEntity; 16 import org.apache.http.impl.client.CloseableHttpClient; 17 import org.apache.http.impl.client.DefaultHttpClient; 18 import org.apache.http.impl.client.HttpClients; 19 import org.apache.http.util.EntityUtils; 20 21 @SuppressWarnings("deprecation") 22 public class HttpUtils { 23 String cookieStr = ""; 24 25 public String getCookieStr() { 26 return cookieStr; 27 } 28 29 CloseableHttpResponse response = null; 30 31 public CloseableHttpResponse getResponse() { 32 return response; 33 } 34 35 public HttpUtils(String cookieStr) { 36 this.cookieStr = cookieStr; 37 } 38 39 public HttpUtils() { 40 41 } 42 43 public String Get(String url) { 44 CloseableHttpClient httpclient = HttpClients.createDefault(); 45 HttpGet httpget = new HttpGet(url); 46 httpget.setHeader("cookie", cookieStr); 47 httpget.setHeader( 48 HttpHeaders.USER_AGENT, 49 "Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/31.0.1650.63 Safari/537.36"); 50 51 try { 52 response = httpclient.execute(httpget); 53 HttpEntity entity = response.getEntity(); 54 String res = EntityUtils.toString(entity, "UTF-8"); 55 56 return res; 57 } catch (Exception e) { 58 System.err.println(String.format("HTTP GET error %s", 59 e.getMessage())); 60 } finally { 61 try { 62 httpclient.close(); 63 } catch (IOException e) { 64 // e.printStackTrace(); 65 } 66 } 67 return null; 68 } 69 70 public String Post(String url) { 71 CloseableHttpClient httpclient = HttpClients.createDefault(); 72 HttpPost httppost = new HttpPost(url.split("//?")[0]); 73 StringEntity reqEntity = null; 74 try { 75 reqEntity = new StringEntity(url.split("//?")[1], "UTF-8"); 76 } catch (UnsupportedEncodingException e1) { 77 // TODO Auto-generated catch block 78 e1.printStackTrace(); 79 } 80 httppost.setHeader("cookie", cookieStr); 81 reqEntity 82 .setContentType("application/x-www-form-urlencoded;charset=UTF-8"); 83 httppost.setEntity(reqEntity); 84 httppost.setHeader( 85 HttpHeaders.USER_AGENT, 86 "Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/31.0.1650.63 Safari/537.36"); 87 try { 88 response = httpclient.execute(httppost); 89 Header[] headers = response.getAllHeaders(); 90 for (Header h : headers) { 91 String name = h.getName(); 92 String value = h.getValue(); 93 if ("Set-Cookie".equalsIgnoreCase(name)) { 94 cookieStr += subCookie(value); 95 //System.out.println(cookieStr); 96 // break; 97 } 98 } 99 HttpEntity entity = response.getEntity();100 101 return EntityUtils.toString(entity, "UTF-8");102 } catch (Exception e) {103 System.err.println(String.format("HTTP POST error %s",104 e.getMessage()));105 } finally {106 try {107 httpclient.close();108 } catch (IOException e) {109 // e.printStackTrace();110 }111 }112 return null;113 }114 115 public String GetLoginCookie(String url) {116 CloseableHttpClient httpclient = HttpClients.createDefault();117 HttpGet httpget = new HttpGet(url);118 httpget.setHeader("Cookie", cookieStr);119 httpget.setHeader(120 HttpHeaders.USER_AGENT,121 "Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/31.0.1650.63 Safari/537.36");122 try {123 response = httpclient.execute(httpget);124 Header[] headers = response.getAllHeaders();125 for (Header h : headers) {126 String name = h.getName();127 String value = h.getValue();128 if ("Set-Cookie".equalsIgnoreCase(name)) {129 cookieStr = subCookie(value);130 return cookieStr;131 }132 133 }134 } catch (Exception e) {135 System.err.println(String.format("HTTP GET error %s",136 e.getMessage()));137 } finally {138 try {139 httpclient.close();140 } catch (IOException e) {141 // e.printStackTrace();142 }143 }144 return "4";// 错误码145 }146 147 public String subCookie(String value) {148 int end = value.indexOf(";");149 return value.substring(0, end + 1);150 }151 152 public InputStream GetImage(String url) {153 InputStream is = null;154 HttpClient httpclient = new DefaultHttpClient();155 HttpGet httpGet = new HttpGet(url);156 if (cookieStr != null)157 httpGet.setHeader("Cookie", cookieStr);158 HttpResponse response;159 try {160 response = httpclient.execute(httpGet);161 if (HttpStatus.SC_OK == response.getStatusLine().getStatusCode()) {162 HttpEntity entity = response.getEntity();163 if (entity != null) {164 //System.out.println(entity.getContentType());165 // 可以判断是否是文件数据流166 //System.out.println(entity.isStreaming());167 // File storeFile = new File("F://code.jpg");168 // FileOutputStream output = new169 // FileOutputStream(storeFile);170 // 得到网络资源并写入文件171 InputStream input = entity.getContent();172 is = input;173 // byte b[] = new byte[1024];174 // int j = 0;175 // while ((j = input.read(b)) != -1) {176 // output.write(b, 0, j);177 // }178 // output.flush();179 // output.close();180 }181 }182 } catch (ClientProtocolException e) {183 // TODO Auto-generated catch block184 e.printStackTrace();185 } catch (IOException e) {186 // TODO Auto-generated catch block187 e.printStackTrace();188 }189 return is;190 }View Code3、简单的测试Test类。 1 package com.debughao.down; 2 3 import java.util.ArrayList; 4 import java.util.List; 5 import java.util.Scanner; 6 7 import org.jsoup.Jsoup; 8 import org.jsoup.nodes.Document; 9 import org.jsoup.nodes.Element;10 import org.jsoup.select.Elements;11 12 import com.debughao.bean.Course;13 14 public class Test {15 16 public static void main(String[] args) {17 HttpUtils http = new HttpUtils("stat_uuid=1436867409341663197461; uname=QQ_rwe4zg5t; uid=3812752; code=LZ8XF1; "18 + "authcode=b809MIxLGp8syQcnuAAdIT9PuCEH2%2FuiyvRuuLALSxb6z6iGoM3xcihNJKzHK%2BAZWzVIGFAW0QrBYiSLmHN1qnhi0YQLmBeWeqkJHXh5xsoylWuRCFmRDJZyUtAGr3U; "19 + "level_id=3; is_expire=0; domain=debughao; stat_fromWebUrl=; stat_ssid=1439813138264;"20 + " connect.sid=s%3A5xux57xcLyCBheevR40DUa0beJD_ok-S.0aTnwfjSvm7A49zydLGbtXy7vdCGfH7lB7MwmZURppQ; "21 + "QINGCLOUDELB=37e16e60f0cd051b754b0acf9bdfd4b5d562b81daa2a899c46d3a1e304c7eb2b|VcWiq|VcWiq; "22 + "_ga=GA1.2.889563867.1436867384; _gat=1; Hm_lvt_f3c68d41bda15331608595c98e9c3915=1438945833,1438947627,1438995076,1438995133;"23 + " Hm_lpvt_f3c68d41bda15331608595c98e9c3915=1439015591; MECHAT_LVTime=1439015591174; MECHAT_CKID=cookieVal=006600143686858016573509; "24 + "undefined=; stat_isNew=0");25 Scanner sc=new Scanner(System.in);26 String url= sc.nextLine();27 sc.close();28 String res = http.Get(url);29 Document doc = getDocByRes(res);30 List<Course> videos = getVideoList(doc);31 for (Course video : videos) {32 System.out.println(video.getLinkText());33 }34 for (Course video : videos) {35 String urls = video.getLinkHref();36 String res2 = http.Get(urls);37 Document doc1 = getDocByRes(res2);38 getVideoLink(doc1);39 40 }41 }42 43 private static Document getDocByRes(String res) {44 // TODO Auto-generated method stub45 Document doc = null;46 doc = Jsoup.parse(res);47 return doc;48 }49 50 public static List<Course> getVideoList(Element doc) {51 Elements links;52 List<Course> courses = new ArrayList<Course>();53 Course course = null;54 Elements results1 = doc.getElementsByClass("lessonvideo-list");55 String title = doc.getElementsByTag("title").text();56 System.out.println(title);57 for (Element element : results1) {58 links = element.getElementsByTag("a");59 for (Element link : links) {60 String linkList = link.attr("href");61 String linkText = link.text();62 // System.out.println(linkText);63 course = new Course();64 course.setLinkHref(linkList);65 course.setLinkText(linkText);66 courses.add(course);67 }68 }69 return courses;70 }71 72 public static void getVideoLink(Document doc) {73 Elements results2 = doc.select("source");74 String mp4Links = results2.attr("src");75 System.out.println(mp4Links);76 }77 }View Code4、以下是运行结果：1 http://www.jikexueyuan.com/course/1748.html 2 自定义 View 基础和原理-极客学院 3 1.编写自己的自定义 View（上） 4 2.编写自己的自定义 View（下） 5 3.加入逻辑线程 6 4.提取和封装自定义 View 7 5.在 xml 中定义样式来影响显示效果 8 http://cv3.jikexueyuan.com/201508082007/99549fa37069a39a2e128278ee60768c/course/1501-1600/1557/video/4278_b_h264_sd_960_540.mp4 9 http://cv3.jikexueyuan.com/201508082007/a068be74f7f31900e128f109523b0925/course/1501-1600/1557/video/4279_b_h264_sd_960_540.mp410 http://cv3.jikexueyuan.com/201508082008/bf216e06770e9a9b0adda34ea4d01dfc/course/1501-1600/1557/video/4280_b_h264_sd_960_540.mp411 http://cv3.jikexueyuan.com/201508082008/75b51573a75458848136e61e848d1ae7/course/1501-1600/1557/video/4281_b_h264_sd_960_540.mp412 http://cv3.jikexueyuan.com/201508082008/ca20fad3e1bc622aa64bbfa7d2b768dd/course/1501-1600/1557/video/5159_b_h264_sd_960_540.mp4打开迅雷新建任务就可以下载。
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