//models/contents.js
var mongoose = require('mongoose');
module.exports = new mongoose.Schema({
    //关联字段 - 内容分类的id
    category:{
        type:mongoose.Schema.Types.ObjectId,
        ref:'Content'    
    },
    title:String,    
    description:{
        type:String,
        default:''
    },
    content:{
        type:String,
        default:''
    }
});

//schema/content.js

var mongoose = require('mongoose');
var contentsSchema = require('../schemas/contents');
module.exports = mongoose.model('Content',contentsSchema);


//routers/admin.js

router.post('/content/add',function(req,res){
    console.log(req.body)
})
打印的不是id而是[object Object]   这是什么原因
{ category: '[object Object]',
  title: 'aaa',
  description: 'aaaa',
  content: 'aaaa' }