java爬虫入门--用jsoup爬取汽车之家的新闻

概述

使用jsoup来进行网页数据爬取。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。

详细

代码下载：http://www.demodashi.com/demo/10220.html

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是基于MIT协议发布的，可放心使用于商业项目

第一步：项目预览

第二步：代码实现

主程序为GrapNews类，实现了从汽车网摘取相关内容的功能。GrapNews有main函数，执行即可。

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package net.sinolbs.ycd.news;
 
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
 
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;
 
/**
 * TODO
 * 2017年5月21日上午12:25:30
 */
public class GrapNews {
     
    public static boolean isContainChinese(String str) {
        Pattern p = Pattern.compile("[\u4e00-\u9fa5]");
        Matcher m = p.matcher(str);
        if (m.find()) {
            return true;
        }
        return false;
    }
     
    /**
     * 从笑话集抓取笑话
     * @param size
     * @param baseUrl
     * @param domainName
     * @param newsListClassOrId
     * @param classOrId
     * @param newsULIndex
     * @param newsContentClassOrId
     * @param titleTagOrClass
     * @param dateTag
     * @return
     */
    public static ArrayList<News> getNewsFromJokeji(int size,String baseUrl,String domainName,
            String newsListClassOrId,int newsULIndex,
            String newsContentClassOrId,String titleTagOrClass,String dateTag){
        ArrayList<News> newsList = new ArrayList<News>();
        Document doc;
        Element element =null;
        Element title =null;
        News news = null;
        try {
            doc = Jsoup.connect(baseUrl).timeout(10000).get();
            element = (Element) doc.getElementsByClass(newsListClassOrId).first();
            Elements elements = element.getElementsByTag("li");
            if(elements!=null&&elements.size()>0){
                for(Element ele:elements){
                    news = new News();
                    title = ele.select("a").first();
                    if(title==null){
                        continue;
                    }
                    news.setTitle(title.getElementsByTag(titleTagOrClass).text());
                    if(news.getTitle()==null||news.getTitle().equals("")){
                        continue;
                    }
                    news.setHref(domainName+title.attr("href"));
                    if(dateTag!=null){
                        String date=ele.select("i").text();
                        news.setDate(date);
                    }
                    String newsUrl =news.getHref();
                    if (isContainChinese(news.getHref())) {
                        newsUrl = URLEncoder.encode(news.getHref(), "utf-8")
                                .toLowerCase().replace("%3a", ":").replace("%2f", "/");
                    }
                    Document newsDoc = Jsoup.connect(newsUrl).timeout(10000).get();
                    String text=newsDoc.getElementById(newsContentClassOrId).html();
                    text=deleteImg(text);
                    text=deleteA(text);
                     StringBuffer textBuffer=new StringBuffer(5);
                     textBuffer.append("<!DOCTYPE html><html><head><meta name=\"content-type\" content=\"text/html; charset=UTF-8\">");
                     textBuffer.append("</head><body>");
                     textBuffer.append(deleteSource(text));
                     textBuffer.append("</body></html>");
                     news.setContent(textBuffer.toString());
                     news.setContent(textBuffer.toString());
                     System.out.println("标题====="+news.getTitle());
                     System.out.println("href====="+news.getHref());
                     System.out.println("content====="+news.getContent());
                     newsList.add(news);
                    if(newsList.size()==size){
                        break;
                    }
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return newsList;
    }
 
    /**
     * 从汽车之家抓新闻
     * @param size
     * @param baseUrl
     * @param domainName
     * @param newsListId
     * @param newsContentClass
     * @param titleTagOrClass
     * @param limitHref
     * @param dateTag
     * @param needDeleteAlt
     * @return
     */
    public static ArrayList<News> getNewsFromCarHome(int size,String baseUrl,String domainName,String newsListId,
            String newsContentClass,String titleTag,String dateTag,String needDeleteAlt){
        ArrayList<News> newsList = new ArrayList<News>();
        Document doc;
        Elements elements =null;
        Element title =null;
        News news = null;
        try {
            doc = Jsoup.connect(baseUrl).timeout(10000).get();
            elements = (Elements) doc.getElementById(newsListId).children();
            if(elements!=null&&elements.size()>0){
                for(Element ele:elements){
                    news = new News();
                    title = ele.select("a").first();
                    if(title==null){
                        continue;
                    }
                    news.setTitle(title.getElementsByTag(titleTag).text());
                    if(news.getTitle()==null||news.getTitle().equals("")){
                        continue;
                    }
                    news.setHref(domainName+title.attr("href"));
                    if(dateTag!=null){
                        String date=ele.select("i").text();
                        news.setDate(date);
                    }
                    String newsUrl =news.getHref();
                    if (isContainChinese(news.getHref())) {
                        newsUrl = URLEncoder.encode(news.getHref(), "utf-8")
                                .toLowerCase().replace("%3a", ":").replace("%2f", "/");
                    }
                    Document newsDoc = Jsoup.connect(newsUrl).timeout(10000).get();
                    String text=newsDoc.getElementsByClass(newsContentClass).html();
                    if(text.indexOf("余下全文")>0||text.indexOf("未经许可")>0
                            ||text.indexOf("禁止转载")>0||text.indexOf("公众号")>0||text.indexOf("公众账号")>0){
                        continue;
                    }
                     text=replaceImgSrcFromDataSrc(text,true,needDeleteAlt);
                     int index=text.lastIndexOf("（");
                     if(index>0){
                         text=text.substring(0,index);
                     }
                     StringBuffer textBuffer=new StringBuffer(5);
                     textBuffer.append("<!DOCTYPE html><html><head><meta name=\"content-type\" content=\"text/html; charset=UTF-8\">");
                     textBuffer.append("</head><body>");
                     textBuffer.append(deleteSource(text));
                     textBuffer.append("</body></html>");
                     news.setContent(textBuffer.toString());
                     news.setContent(textBuffer.toString());
                     System.out.println("标题====="+news.getTitle());
                     System.out.println("href====="+news.getHref());
                     System.out.println("content====="+news.getContent());
                     newsList.add(news);
                    if(newsList.size()==size){
                        break;
                    }
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return newsList;
    }
     
     
     
    public static String getVideoFromMiaoPai(String baseUrl) throws Exception{
        Document doc= Jsoup.connect(baseUrl).timeout(10000).get();
        String html=doc.html().trim();
        return getUrlFromMiaoPaiHtml(html);
    }
     
    public static String getUrlFromMiaoPaiHtml(String html){
        int startIndex=html.indexOf("videoSrc");
        int endIndex=html.indexOf("poster");
        String videoUrl=html.substring(startIndex+11,endIndex+5);
        int index=videoUrl.indexOf('"');
        if(index>0){
            return videoUrl.substring(0, index);
        }
        return videoUrl;
    }
     
    public static String getVideoPhotoFromMiaoPaiHtml(String html){
        System.out.println(html);
        int startIndex=html.indexOf("poster");
        int index=html.substring(startIndex).indexOf("jpg");
        return html.substring(startIndex+9,startIndex+index+3);
    }
     
    public static void main(String[] args) throws Exception{
        getNewsFromCarHome(2,"http://m.autohome.com.cn/channel","http://m.autohome.com.cn","list","details","h4","time","汽车之家");
        getNewsFromJokeji(3,"http://www.jokeji.cn/list.htm","http://www.jokeji.cn","list_title",1,"text110","a","i");
        getNewsFromSouHu(20,"http://m.sohu.com/c/1592/","a",null,null);
    }
     /**
     * 从秒拍抓视频
     * @param size
     * @param baseUrl
     * @param domainName
     * @param newsListId
     * @param newsContentClass
     * @param titleTagOrClass
     * @param limitHref
     * @param dateTag
     * @param needDeleteAlt
     * @return
     */
    public static ArrayList<News> getVideoFromMiaopai(int size,String baseUrl){
        ArrayList<News> newsList = new ArrayList<News>();
        try {
            News news = null;
            Element videoEmement=null;
            Document doc = null;
            String videoUrl=null;
            doc = Jsoup.connect(baseUrl).timeout(10000).get();
            Elements    elements = doc.getElementsByClass("videoCont");
            String videoDetailUrl="";
            if(elements!=null&&elements.size()>0){
                for(Element ele:elements){
                videoEmement=ele.getElementsByClass("MIAOPAI_player").first();
                String videoId=videoEmement.attr("data-scid").toString();
                String videoPhotoUrl=videoEmement.attr("data-img").toString();
                String videoTitle=ele.getElementsByClass("viedoAbout").first().getElementsByTag("p").text();
                System.out.println("视频id"+videoId);
                System.out.println("视频封面url"+videoPhotoUrl);
                System.out.println("视频标题"+videoTitle);
                news = new News();
                if(videoId!=null){
                    news.setTitle(videoTitle);
                    videoDetailUrl="http://www.miaopai.com/show/"+videoId+".html";
                    doc = Jsoup.connect("http://www.miaopai.com/show/"+videoId+".html").timeout(10000).get();
                    System.out.println("视频详情url========"+videoDetailUrl);
                    news.setHref("http://m.miaopai.com/show/"+videoId);
                    news.setPhotoUrl(videoPhotoUrl);
                }
                if(doc!=null){
                     videoUrl=getUrlFromMiaoPaiHtml(doc.html());
                }
                if(videoUrl!=null){
                     news.setContent(createVideoHtml(videoUrl, videoPhotoUrl));
                     System.out.println("视频url====="+videoUrl);
                     System.out.println("视频html======"+news.getContent());
                     newsList.add(news);
                }
                
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return newsList;
    }
 
    public static String createVideoHtml(String videoUrl,String videoPhotoUrl) {
        Document doc;
        StringBuffer textBuffer = new StringBuffer(5);
        textBuffer.append("<!DOCTYPE html><html><head><meta name=\"content-type\" content=\"text/html; charset=UTF-8\">");
        textBuffer.append("</head><body>");
        textBuffer.append("<div align=\"center\">");
        textBuffer.append(" <video></video> </div>");
        textBuffer.append("</body></html>");
        doc = Jsoup.parse(textBuffer.toString());
        doc.getElementsByTag("body").attr("style", "height:400px;");
        doc.getElementsByTag("video").attr("style", "width:100%;max-height:400px;")
            .attr("poster", videoPhotoUrl).attr("autoplay", "autoplay")
                .attr("controls", "controls").attr("src", videoUrl);
        return doc.toString();
    }
     
    /**
     * 从搜狐抓新闻
     * @param size
     * @param baseUrl
     * @param domainName
     * @param newsListId
     * @param newsContentClass
     * @param titleTagOrClass
     * @param limitHref
     * @param dateTag
     * @param needDeleteAlt
     * @return
     */
    public static ArrayList<News> getNewsFromSouHu(int size,String baseUrl,
            String titleTag,String dateTag,String needDeleteAlt){
        ArrayList<News> newsList = new ArrayList<News>();
        Document doc;
        Element element =null;
        Element title =null;
        News news = null;
        try {
            doc = Jsoup.connect(baseUrl).timeout(10000).get();
            element =doc.getElementsByTag("section").get(2);
            element = element.getElementsByClass("headlines").get(0);
             Elements elements=element.children(); 
            if(elements!=null&&elements.size()>0){
                for(Element ele:elements){
                    news = new News();
                    title = ele.select("a").first();
                    if(title==null){
                        continue;
                    }
                    news.setTitle(title.getElementsByTag(titleTag).text());
                    if(news.getTitle()==null||news.getTitle().equals("")
                            ||news.getTitle().indexOf("广告")>0||news.getTitle().indexOf("视频")>0){
                        continue;
                    }
                    news.setHref("https://m.sohu.com"+title.attr("href"));
                    if(dateTag!=null){
                        String dateStr=ele.select(dateTag).first().text();
                        news.setDate(dateStr);
                    }
                    String newsUrl =news.getHref();
                    if (isContainChinese(news.getHref())) {
                        newsUrl = URLEncoder.encode(news.getHref(), "utf-8")
                                .toLowerCase().replace("%3a", ":").replace("%2f", "/");
                    }
                    Document newsDoc = Jsoup.connect(newsUrl).timeout(10000).get();
                    String text=newsDoc.getElementsByTag("article").html();
                    if(text.indexOf("未经许可")>0||text.indexOf("禁止转载")>0
                            ||text.indexOf("公众号")>0||text.indexOf("公众账号")>0){
                        continue;
                    }
                    int index=text.indexOf("<p class=\"para\">");
                    int lastIndex=text.indexOf("<div class=\"expend-wp\"> ");
                    if(lastIndex>0){
                         text=text.substring(index,lastIndex);
                    }else if(index>0){
                        text=text.substring(index,text.length());
                    }
                    text=replaceImgSrcFromDataSrc(text,true,null);
                    if(text==null||text.length()==0){
                        continue;
                    }
                     StringBuffer textBuffer=new StringBuffer(5);
                     textBuffer.append("<!DOCTYPE html><html><head>"
                            + "<meta name=\"content-type\" content=\"text/html; charset=UTF-8\">");
                     textBuffer.append("</head><body>");
                     textBuffer.append(deleteSource(text));
                     textBuffer.append("</body></html>");
                     news.setContent(textBuffer.toString());
                     news.setContent(textBuffer.toString());
                     System.out.println("标题====="+news.getTitle());
                     System.out.println("href====="+news.getHref());
                     System.out.println("content====="+news.getContent());
                     newsList.add(news);
                    if(newsList.size()==size){
                        break;
                    }
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return newsList;
    }
     
    private static String deleteImg(String text) {
        return text.replaceAll("<img [^>]*>", "");
    }
     
    private static String deleteA(String text) {
        return text.replaceAll("<a[^>]*>(.*?)</a>", "");
    }
     
    private static String deleteSource(String text) {
        return text.replaceAll("\\(.*?\\)|\\[.*?]", "");
    }
    /**
     * 删除a标签中的href
     * @param content
     * @return
     */
    public static String removeHref(String content){  
        Document document = Jsoup.parse(content);  
        Elements elements = document.select("a[href]");  
        for(Element el:elements){  
            el.removeAttr("href");  
        }  
        return document.html();  
    }  
     
     
    /**
     * 将htmlBody中所有img标签中的src内容替换为原data-src的内容, <br/>
     * 如果不报含data-src,则src的内容不会被替换 <br/>
     * @param htmlBody html内容
     * @param needDeleteAlt 需要剔除的图片的alt信息
     * @param imgUrlNeedAddProtocolPrefix 图片的url是否需要添加http协议前缀
     * @return 返回替换后的内容
     */
    public static String replaceImgSrcFromDataSrc(String htmlBody,
            boolean imgUrlNeedAddProtocolPrefix,String needDeleteAlt) {
        Document document = Jsoup.parseBodyFragment(htmlBody);
        List<Element> nodes = document.select("img");
        int nodeLenth = nodes.size();
        if(nodeLenth==0){
            return htmlBody;
        }
        for (int i = 0; i < nodeLenth; i++) {
            Element e = nodes.get(i);
            String dataSrc = e.attr("data-src");
            if (isNotBlank(dataSrc)) {
                e.attr("src", dataSrc);
                e.removeAttr("data-src");
            }
            String originalSrc = e.attr("original");
            if (isNotBlank(originalSrc)) {
                e.attr("src", "http:"+originalSrc);
                e.removeAttr("originalSrc");
            }
            String originalHiddenSrc = e.attr("original-hidden");
            if (isNotBlank(originalHiddenSrc)) {
                e.attr("src", "http:"+originalHiddenSrc);
                e.removeAttr("original-hidden");
            }
        }
        if (htmlBody.contains("<html>")) {
            if(needDeleteAlt==null&&!imgUrlNeedAddProtocolPrefix){
                return document.toString();
            }else if(needDeleteAlt==null&&imgUrlNeedAddProtocolPrefix){
                return document.toString().replace("src=\"//", "src=\"http://");
            }else if(needDeleteAlt!=null&&imgUrlNeedAddProtocolPrefix){
                return document.toString().replace("src=\"//", "src=\"http://")
                        .replace("alt="+needDeleteAlt, "");
            }
            return document.toString().replace("alt="+needDeleteAlt, "");
        } else {
            if(needDeleteAlt==null&&!imgUrlNeedAddProtocolPrefix){
                return document.select("body>*").toString();
            }else if(needDeleteAlt==null&&imgUrlNeedAddProtocolPrefix){
                return document.select("body>*").toString().replace("src=\"//", "src=\"http://");
            }else if(needDeleteAlt!=null&&imgUrlNeedAddProtocolPrefix){
                return document.select("body>*").
                        toString().replace("src=\"//", "src=\"http://").replace("alt="+needDeleteAlt, "");
            }
            return document.select("body>*").toString().replace("alt="+needDeleteAlt, "");
        }
     
    }
     
     
    private static boolean isNotBlank(String str){
        if(str == null)
            return false;
        else if(str.trim().length() == 0)
            return false;
        else
            return true;
    }
}

还有一个载体类，用于把趴下来的网页内容进行封装到一个类里面。

package net.sinolbs.ycd.news;
 
/**
 * 新闻数据载体
 */
public class News {
    private int id;
    private String title;
    private String href;
    private String content;
    private String date;
    private String photoUrl;
    public News() {
    }
 
    public News(String title, String href, String content, int id) {
        this.title = title;
        this.content = content;
        this.href = href;
        this.id = id;
    }
 
    public int getId() {
        return id;
    }
 
    public void setId(int id) {
        this.id = id;
    }
 
 
    public String getTitle() {
        return title;
    }
 
    public void setTitle(String title) {
        this.title = title;
    }
 
    public String getHref() {
        return href;
    }
 
    public void setHref(String href) {
        this.href = href;
    }
 
    public String getContent() {
        return content;
    }
 
    public void setContent(String content) {
        this.content = content;
    }
 
    public String getDate() {
        return date;
    }
 
    public void setDate(String date) {
        this.date = date;
    }
 
    public String getPhotoUrl() {
        return photoUrl;
    }
 
    public void setPhotoUrl(String photoUrl) {
        this.photoUrl = photoUrl;
    }
     
}