从网页中通过正则表达式获取标题、URL和发表时间

  为了从几个网站抽取内容，聚合到一起。我于2012年写了一个程序，从多个网站通过结构化方法抽取内容。然后写入数据库，形成一个网站。

（1）正则表达式抽取

  首先，从数据库中读取内容抽取规则：

ArrayList<RuleBean> rbList = ruleDao.QueryAllRule();
 抽取规则的表结构如下：

 配置的抽取规则如下：

   其次，读取网页内容，并通过起始标签抽取出内容，然后通过正则表达式读取出网址URL、标题和发表时间。

直接上代码如下：






1 private static void doCrawl(RuleBean rb) {     
 2         String urlContent = getUrlContent(rb.getCrawlUrl(),rb.getEncode());
 3         if("error".equalsIgnoreCase(urlContent)){
 4             return;
 5         }
 6         String contentArea = getContentArea(urlContent, rb.getAreaBegin(),
 7                 rb.getAreaEnd());
 8  
 9         Pattern pt = Pattern.compile(rb.getRegex());
10         Matcher mt = pt.matcher(contentArea);
11             
12         TitleAndUrlBean tuBean;
13         while (mt.find()) {
14             tuBean = new TitleAndUrlBean();
15             tuBean.setAppName(rb.getAppName());
16             tuBean.setInfoArea(rb.getInfoArea());
17 
18             String rowContent = mt.group();
19             rowContent = rowContent.replaceAll(rb.getRemoveRegex(), "");
20 
21             // 获取标题
22             Matcher title = Pattern.compile(rb.getTitleRegex()).matcher(
23                     rowContent);
24             while (title.find()) {
25                 String s = title.group().replaceAll("<u>|</u>|>|</a>|\\[.*?\\]|</l>","");
26                 if(s ==null || s.trim().length()<=0){
27                     s = "error";
28                 }
29                 tuBean.setTitle(s);
30                 
31             }
32 
33             // 获取网址
34             Matcher myurl = Pattern.compile(rb.getUrlRegex()).matcher(
35                     rowContent);
36             while (myurl.find()) {
37                 String u = myurl.group().replaceAll(
38                         "href=|\"|>|target=|_blank|title", "");
39                 u = u.replaceAll("\'|\\\\", "");
40                 
41                 if(u!=null && (u.indexOf("http://")==-1)){
42                     tuBean.setUrl(rb.getPrefix() + u);
43                 }else{
44                     tuBean.setUrl(u);
45                 }            
46             }
47             if(tuBean.getUrl() ==null){
48                 tuBean.setUrl("error");
49             }
50 
51             // 获取时间
52             Matcher d = Pattern.compile(rb.getDateRegex()).matcher(rowContent);
53             while (d.find()) {
54                 tuBean.setDeliveryDate(d.group());
55             }
56 
57             boolean r = TitleAndUrlDAO.Add(tuBean);
58             
59             if (r){
60                 log.info("crawl add " + tuBean.getAppName() + "_"
61                         + tuBean.getInfoArea()+"_"+tuBean.getTitle());
62             
63                 if(tuBean.getAppName().contains("jww")){
64                     Cache cTeach = CacheManager.getCacheInfo("index_teach");
65                     if(cTeach!=null){
66                         teachList  = (List<TitleAndUrlBean>) cTeach.getValue();
67                     }
68                     
69                     teachList.add(tuBean);
70                     if(teachList.size()>5){
71                         teachList.remove(0);    
72                     }
73                     cTeach.setValue(teachList);
74                     cTeach.setTimeOut(-1);
75                     CacheManager.putCache("index_teach", cTeach);
76                 } 
77             }
78         }
79         System.out.println("end crawl "+rb.getCrawlUrl());
80     }



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(2) dwr返回内容的抽取


    在当时dwr是比较流行的技术，为了抽取dwr的内容，着实花了一番功夫。


首先通过httpClient获取内容










 1     public static void startCrawl() throws Exception{
 2         System.out.println("begin crawl xb");
 3         DefaultHttpClient httpclient = new DefaultHttpClient();
 4         HttpResponse response = null;
 5         HttpEntity entity = null;
 6         httpclient.getParams().setParameter(ClientPNames.COOKIE_POLICY,
 7                 CookiePolicy.BROWSER_COMPATIBILITY);
 8         HttpPost httpost = new HttpPost(
 9                 "http://xxxxxx/Tzgg.getMhggllList.dwr");
10         
11         //公告公示 nvps.add(new BasicNameValuePair("c0-e3", "string:03"));
12         
13         List<NameValuePair> nvps = new ArrayList<NameValuePair>();
14         
15 
16         nvps.add(new BasicNameValuePair("callCount", "1"));
17         nvps.add(new BasicNameValuePair("page", "/tzggbmh.do"));
18         nvps.add(new BasicNameValuePair("c0-scriptName", "Tzgg"));
19         nvps.add(new BasicNameValuePair("c0-methodName", "getMhggllList"));
20         nvps.add(new BasicNameValuePair("c0-id", "0"));
21         nvps.add(new BasicNameValuePair("c0-e1", "string:0"));
22         nvps.add(new BasicNameValuePair("c0-e2", "string:0"));
23         
24         nvps.add(new BasicNameValuePair("c0-e4", "string:%20%20"));
25         nvps.add(new BasicNameValuePair("c0-e5", "string:rsTable"));
26         nvps.add(new BasicNameValuePair(
27                 "c0-param0",
28                 "Array:[reference:c0-e1,reference:c0-e2,reference:c0-e3,reference:c0-e4,reference:c0-e5]"));
29         nvps.add(new BasicNameValuePair("c0-e6", "number:20"));
30         nvps.add(new BasicNameValuePair("c0-e7", "number:1"));
31         nvps.add(new BasicNameValuePair("c0-param1",
32                 "Object_Object:{pageSize:reference:c0-e6, currentPage:reference:c0-e7}"));
33         nvps.add(new BasicNameValuePair("batchId", "0"));
34 
35         int infoArea = 1;
36         while(infoArea <4){
37             nvps.add(new BasicNameValuePair("c0-e3", "string:0"+infoArea));
38 
39             httpost.setEntity(new UrlEncodedFormEntity(nvps));
40 
41             response = httpclient.execute(httpost);
42             entity = response.getEntity();
43             try {
44                 String responseString = null;
45                 if (response.getEntity() != null) {
46                     responseString = EntityUtils.toString(response.getEntity());
47                     if(1 == infoArea){
48                         extractData(responseString,"事务通知");
49                         infoArea = 3;
50                     }
51 
52                 }
53             } finally {
54                 
55             }    
56             
57             
58             
59         }
60         
61         System.out.println("end crawl xb");
62         httpclient.getConnectionManager().shutdown();
63     }



View Code




 




然后通过正则表达式抽取










 1 private static void extractData(String content,String infoArea) throws Exception{
 2         TitleAndUrlDAO tuDao = new TitleAndUrlDAO();
 3         TitleAndUrlBean tuBean;
 4 
 5         Pattern pt = Pattern.compile("llcs.*?a>");
 6         Matcher mt = pt.matcher(content);
 7 
 8         Cache c = new Cache();
 9         while (mt.find()) {
10             tuBean = new TitleAndUrlBean();
11             tuBean.setAppName("info_xb");
12             tuBean.setInfoArea(infoArea);
13 
14             String s2 = mt.group();
15 
16             // 获取标题
17             Matcher title = Pattern.compile("title.*?>").matcher(s2);
18             while (title.find()) {
19                 String s = title.group().replaceAll("title=|>", "");
20                 
21                 tuBean.setTitle(unicodeToString(s));
22             }
23 
24             // 获取网址
25             Matcher myurl = Pattern.compile("ID=.*?;").matcher(s2);
26             while (myurl.find()) {
27                 String prefix = "http://XXXX/tzggbmh.do?theAction=view&parameter.id=";
28 //                System.out.println("网址:" + prefix
29 //                        + myurl.group().replaceAll("ID=|;|\"", ""));
30 
31                 tuBean.setUrl(prefix + myurl.group().replaceAll("ID=|;|\"", ""));
32             }
33 
34             // 获取时间
35             Matcher d = Pattern.compile("[0-9]{4}-[0-9]{2}-[0-9]{1,2}")
36                     .matcher(s2);
37             while (d.find()) {
38                 tuBean.setDeliveryDate(d.group());
39             }
40 
41             boolean r = tuDao.Add(tuBean);
42            
43             if (r){
44                 log.info("crawl add " + tuBean.getAppName() + "_"
45                         + tuBean.getInfoArea()+"_"+tuBean.getTitle());
46                     
47                 Cache cNotice = CacheManager.getCacheInfo("index_notice");
48                 if(cNotice!=null){
49                 xb_noticeList = (List<TitleAndUrlBean>) cNotice.getValue();
50                 }
51                 
52                 xb_noticeList.add(tuBean);
53                 if(xb_noticeList.size()>5){
54                     xb_noticeList.remove(0);
55                 }
56                 
57                 c.setValue(xb_noticeList);
58                 c.setTimeOut(-1);
59                 CacheManager.putCache("index_notice", c);                        
60             }
61         }
62     }



View Code








 本文使用的抽取方法代码，写于2012年，每次网站结构变化的时候需要重新配置规则。


不知道这么多年过来，是否有智能的方法获取网站这种半结构化数据。


如果有，请留言告知，谢谢！









            

            
posted @ 
2020-01-03 18:12 
siwei718 
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