通过商品的url获取促销价,天猫淘宝的促销价并不是直接生成的,而是通过js间接生成的。所以通过jsoup等工具无法抓取。
首先是尝试使用htmlUnit,因为其可以,模拟浏览器运行js、css。经试验,htmlunit确实可以运行js,尝试抓取我自己的网站,可成功获取ajax、js生成的内容。但在抓取淘宝网站时出现异常,htmlunit对网站内容的格式有一定的要求,于是只能想其他办法(以后再尝试此方法)。
接着使用httpwatch分析淘宝的请求,发现其中一个请求返回的值中有促销价的信息。
这个请求有2个关键点,关键1:参数itemid(就是商品的id)。关键2:是请求header的Referer。
具体代码如下:
第一篇博客
- import java.io.BufferedReader;
- import java.io.IOException;
- import java.io.InputStreamReader;
- import java.io.UnsupportedEncodingException;
- import java.util.HashMap;
- import java.util.Map;
- import org.apache.http.HttpResponse;
- import org.apache.http.client.ClientProtocolException;
- import org.apache.http.client.HttpClient;
- import org.apache.http.client.methods.HttpGet;
- import org.apache.http.client.methods.HttpPost;
- import org.apache.http.impl.client.DefaultHttpClient;
- public class Test4Taobao {
- public static void main(String[] args) throws ClientProtocolException, IOException {
- HttpClient httpclient = new DefaultHttpClient();
- String url="http://detail.tmall.com/item.htm?spm=a230r.1.14.44.RoTYht&id=43508885384&ns=1&abbucket=20";
- String id=getStrByPrePost(url, "id=", "&");//根据url获取商品的id
- if(id!=null){
- //组装出获取商品信息的url
- String detailUrl="http://mdskip.taobao.com/core/initItemDetail.htm?itemId="+id+"×tamp=1429065419751&tgTag=false&cartEnable=true&addressLevel=2&progressiveSupport=false&isUseInventoryCenter=false&household=false¬AllowOriginPrice=false&isRegionLevel=false&sellerUserTag=303632416&sellerUserTag2=18020085046181888&tmallBuySupport=true&isAreaSell=false&queryMemberRight=true&isIFC=false&sellerUserTag3=70368779862144&sellerUserTag4=8800522208643&service3C=true&tryBeforeBuy=false&isSecKill=false&isForbidBuyItem=false&sellerPreview=false&itemTags=843,1163,1478,1483,1547,1611,1803,1867,2049,2059,2443,2507,2635,3787,3974,4166,4555,4811,5323,21762,21826,25282,28802,29122,34178,56130,56194&isApparel=false&offlineShop=false&showShopProm=false&callback=setMdskip";
- HttpGet get = new HttpGet(detailUrl);
- get.addHeader("Referer", url);//Referer必须要设置
- HttpResponse response = httpclient.execute(get);
- String content = getContent(response);
- content=getStrByPrePost(content, "setMdskip(", ")");
- //返回的内容是json格式,可以通过gson等来解析,为了方便,此处直接截取。
- System.out.println("商品信息:"+content);
- String promotionPrice = getStrByPrePost(content, "promotionList", null);
- promotionPrice = getStrByPrePost(promotionPrice, "\"price\":", ",");
- System.out.println("商品价格:"+promotionPrice);
- }
- }
- /**
- * 获取返回内容的string
- * @param response
- * @return
- * @throws IllegalStateException
- * @throws IOException
- */
- private static String getContent(HttpResponse response) throws IllegalStateException, IOException {
- java.io.InputStream is = response.getEntity().getContent();
- BufferedReader br = new BufferedReader(new InputStreamReader(is, "GBK"));//response.getEntity().getContentEncoding().getName()
- String line = "";
- String temp= null;
- while ((temp = br.readLine()) != null) {
- line+=temp;
- }
- return line;
- }
- /**
- * 根据前后的文本截取指定的内容。
- * @param str
- * @param pre
- * @param post
- * @return
- */
- public static String getStrByPrePost(String str,String pre,String post){
- if(str!=null){
- if(pre!=null){
- int s = str.indexOf(pre);
- if(s>-1){
- str = str.substring(s+pre.length(), str.length());
- }else{
- return null;
- }
- }
- if(post!=null){
- int e = str.indexOf(post);
- if(e>-1){
- str = str.substring(0,e);
- }else{
- return null;
- }
- }
- }
- return str;
- }
- }
to be continued