javascript – .get()需要回调函数,但有一个[object Undefined]

我在routes.js中写下面的代码

var docs = require('../app/controllers/genericController');
    app.post('/newdoc',docs.createMainDoc);
    app.get('/listdoc',docs.listDocs);

并在genericController中：

exports.listDoc = function(req,res) {
    var Model = mongoose.model(req.model); //i dont know,if this is defined or undefined. Actually i am not able to check it. Even if i comment whole body of this exports.listDoc,then also i get the same error. just assume here that here i am getTing model.
    Model.find(function(err,models) {
        if (err) {
            res.render('error',{
                status: 500
            });
        } else {
            res.jsonp(models);
        }
    });
};

我得到错误：

.get() requires callBACk functions but got a [object Undefined]

如何解决？