app.get('/knowledge', function (req, res, next) {    var listUid = req.query.listUid;    var url = "http://www.lengdou.net/page/" + listUid + "/";    // console.log('--------开始检测--------');    var content = {};    var map = new Array();    superagent        .get(url)        .end(function (err, sres) { // callback            // 常规的错误处理       if (err) {                res.send('{\"code\":\"300\",\"msg\":\"读取出错!!\"}');            }            try {                var $ = cheerio.load(sres.text);                var lists = $(".list").each(function (index, element) {                    var text = $(this).find(".list-content").find("p").text();                    var url = $(this).find(".list-content").find("img").attr("src");                    console.log(text + url + "\n");                    var content = {};                    content['text'] = text;                    content['url'] = url;                    map[index] = content;                });                res.send(JSON.stringify(map));            } catch (e) {            }        });});