Node+Express+Mongodb+Angular项目搭建

https://jingyan.baidu.com/article/0964eca21293a88285f53692.html
https://www.cnblogs.com/jone-chen/p/6898986.html
http://www.mamicode.com/info-detail-2612096.html
express 官网https://www.expressjs.com.cn/en/4x/api.html#req
mongoose 官方文档
npm install mongoose
https://mongoosejs.com/docs/index.html#

1. 确认已经安装Node.js

node -v

2. 创建一个目录，作为当前工作目录

mkdir meanApp
cd meanApp

3. 创建 package.json 文件， 指定入口文件 index.js ， 然后一路回车确定

npm init

4. 安装 express 并将其保存到依赖列表

npm install express --save

5. 创建 MongoDB 数据库

npm install mongoose --save

cmd 里使用命令操作数据库

mongo                                               //   进入数据库
use express-demo                          // 创建项目数据库
db.createCollection("users")         //  创建一个集合，即表
db.users.insert({userid:"admin", password: "123456"})  // 在users 表里添加一条记录
db.user.find()                                  // 查看users 表

6. 搭建项目原型

6-1 创建后端express入口文件 app.js ， 并复制以下代码

//  express 导入
var express = require('express');
var app = express();
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
// schema,  routes, 
// mongoose 导入
var mongoose = require('mongoose')

// 连接数据库mongoose
mongoose.connect('mongodb://localhost/databasename', { useNewUrlParser: true })
var db = mongoose.connection;
db.on('error', console.error.bind(console, 'connection error:'));
db.once('open', function() {
'Connected to database  successfully!'
});

//  express  使用
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({extended: true}));

// static 文件
//app.use('/static', express.static(path.join(__dirname, 'public')))

/后台设置跨域访问
app.all(‘*‘, function(req, res, next) {
    res.header("Access-Control-Allow-Origin", "*");
    res.header("Access-Control-Allow-Headers", "X-Requested-With");
    res.header("Access-Control-Allow-Methods","PUT,POST,GET,DELETE,OPTIONS");
    res.header("X-Powered-By",‘ 3.2.1‘)
    res.header("Content-Type", "application/json;charset=utf-8");
    next();
});






module.exports = app;

• 1. Define schema
     Everything in Mongoose starts with a Schema. Each schema maps to a MongoDB collection and defines the shape of the documents within that collection.
     Each key in our code blogSchema defines a property in our documents which will be cast to its associated SchemaType.

var mongoose = require('mongoose');
  var Schema = mongoose.Schema;

  var blogSchema = new Schema({
    title:  String, // String is shorthand for {type: String}
    author: String,
    body:   String,
    comments: [{ body: String, date: Date }],
    date: { type: Date, default: Date.now },
    hidden: Boolean,
    meta: {
      votes: Number,
      favs:  Number
    }
  });

The permitted SchemaTypes are:

• String
• Number
• Date
• Buffer
• Boolean
• Mixed
• ObjectId
• Array
• Decimal128
• Map

• 2. Creating a model

To use our schema definition, we need to convert our blogSchema into a Model we can work with. To do so, we pass it into mongoose.model(modelName, schema):

var Blog = mongoose.model('Blog', blogSchema);

A model is a class with which we construct documents. In this case, each document will be a kitten with properties and behaviors as declared in our schema. Let's create a kitten document representing the little guy we just met on the sidewalk outside:

var silence = new Kitten({ name: 'Silence' });
console.log(silence.name);