node.js实现博客小爬虫的实例代码

var http=require('http');var Promise=require('Bluebird');var cheerio = require('cheerio');var url='http://www.immaster.cn';//博客地址function filterchapters1(html) {//解析文章链接 var $ =cheerio.load(html); var post=$('.post');  var content=[]; post.each(function (item) {  var postid=$(this).find('.tit').find('a').attr('href');  content.push(postid); }) return content;}function filterchapters(html) {//解析每个文章内的内容 var $ =cheerio.load(html); var tit=$('.post .tit').find('a').text(); var postid=$('.tit').find('a').attr('href'); var commentnum=$('.comments-title').text(); commentnum=commentnum.trim(); // commentnum=commentnum.replace('/n',''); var content={tit:tit,url:postid,commentnum:commentnum}; return content;}function getid(url){//爬取首页文章链接 return new Promise(function (resolve,reject) { http.get(url,function (res) { var html = ''; res.on('data',function(data) { html+=data; }); res.on('end',function () { var content=filterchapters1(html) resolve(content);  })}).on('error',function () { reject(e); console.log('抓取出错！') })})}function getpageAsync(url) {//爬取单个页面内容 return new Promise(function (resolve,reject) { console.log('正在爬取……'+url) http.get(url,function (res) { var html = ''; res.on('data',function(data) { html+=data; }); res.on('end',function () { resolve(html);  }) }).on('error',function () { reject(e); console.log('抓取出错！') }) })}getid(url) .then(function(postid){ return new Promise(function (resolve,reject) { var pageurls=[]; postid.forEach(function (id) { pageurls.push(getpageAsync(id)); }) resolve(pageurls); }) }) .then(function(pageurls){ return new Promise.all(pageurls);//让promise对象同时开始运行 }) .then(function (pages) { var coursesData=[]; pages.forEach(function (html) { var courses=filterchapters(html); coursesData.push(courses); })coursesData.forEach(function(v){ console.log('标题：'+v.tit+"/n地址："+v.url+"/n评论："+v.commentnum) }) })