nodejs+koa2 实现模仿springMVC框架

koa2-MVC架构

---------后端技术做前端

环境：nodejs

开发工具：Visual Studio Code(下文简称：VSC)

环境安装，工具安装及中文自行百度，环境调整好后开始进入正题。

1、在硬盘上新增一个文件夹，打开VSC，点击‘添加工作区文件夹"，如果没有欢迎‘使用页面"，点击--文件--新建窗口，效果如下图：

nodejs+koa2 实现模仿springMVC框架

2、添加vsc调试。Shift+ctrl+p，输入框内输入：launch.json

nodejs+koa2 实现模仿springMVC框架

选择刚刚的文件夹

nodejs+koa2 实现模仿springMVC框架

3、目录结构

nodejs+koa2 实现模仿springMVC框架

从低到高one by one

3-1、package.json

{
 "name": "koa2mcv",
 "version": "1.0.0",
 "description": "Hello Koa 2 example with MVC",
 "main": "app.js",
 "scripts": {
  "start": "node app.js"
 },
 "author": "baba",
 "dependencies": {
  "koa": "2.11.0",
  "koa-router": "8.0.8",
  "koa-bodyparser": "4.3.0",
  "koa-static-plus": "0.1.1",
  "koa-view": "2.1.3",
  "koa-jwt": "4.0.0",
  "koa-log4": "2.3.2",
  "jsonwebtoken": "8.5.1",
  "nunjucks": "3.2.1",
  "mime": "2.4.5",
  "mz": "2.7.0"
 }
}

参数介绍：name项目名称、version版本号、description项目描述、main项目启动文件、scripts启动快捷设置，author作者，dependencies第3方中间件名称及版本。

3-2、app.js

//启动服务
require("./config/init").startServer();

启动相关配置，封装到config/init.js中，启动文件直接引用即可。

3-3、views存放html页面

3-4、static存放静态文件，css,js,font等

3-5、src存放业务控制，类似于springMVC中的controller、service。

3-6、config存放核心配置文件。

3-6-1、init.js项目核心。

异常友好处理

function handler(){
 return async (ctx, next) => {

  const start = new Date().getTime();

  var urlReq=ctx.request.url;
  if(urlReq !== "/favicon.ico"){

   console.log(`请求地址：${ctx.request.method} ${urlReq}`);
   try {

    let params =Object.assign({}, ctx.request.query, ctx.request.body);

    if(config["token"].excludeUrl.indexOf(urlReq) == -1 && !tokenFunction.varifyToken(params.token)){
     ctx.status =401;
    }else{
     await next();
    }
   } catch (error) {
    ctx.status=401;
    console.log(`错误！无法获取token参数`);
   }finally{

     let err={};
     if(!ctx.status){
      err.status = 500;
     }else if(ctx.status==200){
      return;
     }else{
      err.status = ctx.status;
     }

     switch(err.status){
      case 404:
       err.url = config["server-name"]+"/static/public/404.html";
       err.message="资源不存在！";
       break;
      case 401:
       err.url = config["server-name"]+"/static/public/10000.html";
       err.message="登陆失效！请重新登陆！";
       break;
      case 500:
       err.url = config["server-name"]+"/static/public/500.html";
       err.message="系统内部错误！";
       break;
     }

     switch(ctx.request.type){
      case "application/json":
       ctx.type = "application/json";
       ctx.body = {errorCode:err.errorCode,message: err.message}
       break;
      default:

       ctx.type = "text/html";
       ctx.redirect(err.url);
       break;
     }
   }
  }
  const ms = new Date().getTime() - start;
  console.log(`请求消耗时间: ${ms}ms`);
 }
}

路由配置

function controller(){

 const router = new koaRouter({
  prefix: config["server-name"]
 });

 function findJsonFile(rootpathStr){

  fs.readdirSync(rootpathStr).forEach(function (item, index) {

   let fPath = path.join(rootpathStr,item);

   let stat = fs.statSync(fPath);

   if(stat.isDirectory() === true) {
    findJsonFile(fPath);
   }

   if (stat.isFile() === true&&fPath.endsWith(".js")) {

    var mapping = require(fPath);
    for (var url in mapping) {
     if (url.startsWith("GET ")) {
      router.get(url.substring(4), mapping[url]);
     } else if (url.startsWith("POST ")) {
      router.post(url.substring(5), mapping[url]);
     } else if (url.startsWith("PUT ")) {
      router.put(url.substring(4), mapping[url]);
     } else if (url.startsWith("DELETE ")) {
      router.del(url.substring(7), mapping[url]);
     }
     console.log(`注册 URL: ${url}`);
    }
   }
  });
 }

 findJsonFile(rootpath + "src");
 return router.routes();
}

视图渲染

function templating() {
 var
  autoescape = config["templating-autoescape"] === null ? true : config["templating-autoescape"],
  noCache = config["templating-noCache"] === null ? false : config["templating-noCache"],
  watch = config["templating-watch"] === null ? false : config["templating-watch"],
  throwOnUndefined = config["templating-throwOnUndefined"] === null ? false :config["templating-throwOnUndefined"],
  env = new nunjucks.Environment(
   new nunjucks.FileSystemLoader(rootpath+"views", {
    noCache: noCache,
    watch: watch,
   }), {
    autoescape: autoescape,
    throwOnUndefined: throwOnUndefined
   });
 if (config["templating-filters"] != null) {
  for (var f in config["templating-filters"]) {
   env.addFilter(f, config["templating-filters"][f]);
  }
 }
 return async (ctx, next) => {
  ctx.render = function (view, model) {
   ctx.response.body = env.render(view, Object.assign({}, ctx.state || {}, model || {}));
   ctx.response.type = "text/html";
  };
  await next();
 };
}

启动构建

function startServer(){

 const app = new koa();

 app.use(koaStaticPlus(rootpath+"static", {
  pathPrefix: config["server-name"]+"/static"
 })
 );
 
 app.use(koaBodyParser());
 
 app.use(handler());
 
 app.use(templating());
 
 app.use(controller());
 
 app.listen(config["server-port"]);

}

3-6-2、config.js项目参数配置。

module.exports ={
 "server-name":"/koa",
 "server-port":3000,
 "templating-noCache":true,
 "templating-watch":true,
 "templating-autoescape":null,
 "templating-throwOnUndefined":null,
 "templating-filters":null,
 "token":{
  "excludeUrl":[
  "/koa/login",
  "/koa/dologin"
  ],
  "timeout":1000 * 60 * 60 * 24 * 7,
  "secret":"jiaobaba"
 }
 

}

3-6-3、token.js项目token相关方法封装。

const jwt = require("jsonwebtoken");
const config = require("./config");
/**
 * 创建token的方法
 */
let createToken = (data)=>{
 let obj = {};
 //存入token的数据
 obj.data = data || {};
 //token的创建时间
 obj.ctime = (new Date()).getTime();
 return jwt.sign(obj,config["token"].secret);
}
/**
 * 验证token是否合法的方法
 * @param {*} token 
 */
let varifyToken = (token)=>{
 let result = null;
 try{
  let {data,ctime,expiresIn} = jwt.verify(token,config["token"].secret);
  let nowTime = (new Date()).getTime();
  if(nowTime-ctime<config["token"].timeout){
   result = data;  
  }
 }catch(error){

 }
 return result;
}

module.exports = {
 createToken,
 varifyToken
};

3-6-4、logger.js项目日志配置文件。

4、项目结构构建结束，接着引入所有依赖包，在终端中执行‘npm install" ,会下载package.json中dependencies所有包，以及这些包所依赖的包。

nodejs+koa2 实现模仿springMVC框架

执行后项目结构会增加两个文件

nodejs+koa2 实现模仿springMVC框架

5、编写测试用例，在src下新建hello.js。

//token
const token = require("../config/token");

var fn_hello = async (ctx, next) => {
 var name = ctx.params.name;
 ctx.response.body = `<h1>Hello, ${name}!</h1>`;
};


var fn_index = async (ctx, next) => {
 ctx.response.body = `<h1>Index</h1>
  <form action="/koa/signin" method="post">
   <p>Name: <input name="name" value=""></p>
   <p>Password: <input name="password" type="password"></p>
   <p><input type="submit" value="Submit"></p>
  </form>`;
};

var fn_signin = async (ctx, next) => {
 var
  name = ctx.request.body.name || "",
  password = ctx.request.body.password || "";
 console.log(`登陆名: ${name}, 密码: ${password}`);
  ctx.response.body = `<h1>Welcome, ${name}!</h1><br/>you token:<br/>${token.createToken({user: name,password: password})}`;
 
};

module.exports = {
 "GET /hello/:name": fn_hello,
 "GET /login": fn_index,
 "POST /dologin": fn_signin
};

6、启动项目

nodejs+koa2 实现模仿springMVC框架