增删改查实例

-index.js

const Koa = require("koa"),
  Router = require("koa-router"),
  path = require("path"),
  render = require("koa-art-template"),
  bodyParser = require("koa-bodyparser"),
  DB = require("./module/db");

const COLLECTION_NAME = "teacher";

const app = new Koa();
const router = new Router();

app.use(bodyParser());

render(app, {
  root: path.join(__dirname, "views"),
  extname: ".html",
  debug: true
});

router.get("/", async ctx => {
  let docs = await DB.find(COLLECTION_NAME);
  await ctx.render("index", { docs });
});

router.get("/addUser", async ctx => {
  await ctx.render("addUser");
});

router.post("/add", async ctx => {
  let {
    result: { n, ok }
  } = await DB.insert(COLLECTION_NAME, ctx.request.body);
  if (ok) {
    ctx.redirect("/");
  }
});

router.get("/edit", async ctx => {
  let { id } = ctx.query;
  let [docs] = await DB.find(COLLECTION_NAME, { _id: DB.getObjectId(id) });
  await ctx.render("edit", { docs });
});

router.post("/doEdit", async ctx => {
  let { _id, ...obj } = ctx.request.body;
  let {
    result: { n, ok }
  } = await DB.updateOne(COLLECTION_NAME, { _id: DB.getObjectId(_id) }, obj);
  if (ok) {
    ctx.redirect("/");
  }
});

router.get("/del", async ctx => {
  let { id } = ctx.query;
  let {
    result: { n, ok }
  } = await DB.removeOne(COLLECTION_NAME, { _id: DB.getObjectId(id) });
  if (ok) {
    ctx.redirect("/");
  }
});

app.use(router.routes()).use(router.allowedMethods());

app.listen(8080);

• module/db.js

const config = require("./config");
const mongodb = require("mongodb");
const MongoClient = mongodb.MongoClient;
const ObjectId = mongodb.ObjectId;
const client = new MongoClient(config.dbUrl, { useUnifiedTopology: true });

class Db {
  static getInstance() {
    if (!Db.instance) {
      Db.instance = new Db();
    }
    return Db.instance;
  }
  constructor() {
    this.dbClient = "";
    this.connect();
  }
  connect() {
    return new Promise((resolve, reject) => {
      if (!this.dbClient) {
        client.connect(err => {
          if (err) {
            reject(err);
          } else {
            this.dbClient = client.db(config.dbName);
            resolve(this.dbClient);
          }
        });
      } else {
        resolve(this.dbClient);
      }
    });
  }
  find(collectionName = "student", json = {}) {
    return new Promise((resolve, reject) => {
      this.connect().then(db => {
        db.collection(collectionName)
          .find(json)
          .toArray((err, docs) => {
            if (err) {
              reject(err);
            } else {
              resolve(docs);
            }
          });
      });
    });
  }
  update() {}
  insertMany(collectionName, insertArr) {
    return new Promise((resolve, reject) => {
      this.connect().then(db => {
        db.collection(collectionName).insertMany(insertArr, (err, result) => {
          if (err) {
            reject(err);
          } else {
            resolve(result);
          }
        });
      });
    });
  }
  insert(collectionName, json) {
    return new Promise((resolve, reject) => {
      this.connect().then(db => {
        db.collection(collectionName).insertOne(json, (err, result) => {
          if (err) {
            reject(err);
          } else {
            resolve(result);
          }
        });
      });
    });
  }
  updateOne(collectionName, json1, json2) {
    return new Promise((resolve, reject) => {
      this.connect().then(db => {
        db.collection(collectionName).updateOne(
          json1,
          { $set: json2 },
          (err, result) => {
            if (err) {
              reject(err);
            } else {
              resolve(result);
            }
          }
        );
      });
    });
  }
  removeOne(collectionName, json) {
    return new Promise((resolve, reject) => {
      this.connect().then(db => {
        db.collection(collectionName).deleteOne(json, (err, result) => {
          if (err) {
            reject(err);
          } else {
            resolve(result);
          }
        });
      });
    });
  }
  getObjectId(id) {
    return ObjectId(id);
  }
}

module.exports = Db.getInstance();

新增了一个设置ObjectId的方法

• module/config.js

// 配置文件
const app = {
  dbUrl: "mongodb://localhost:27017",
  dbName: "student"
};

module.exports = app;

-index.html

<!DOCTYPE html>
<html lang="en" dir="ltr">
  <head>
    <meta charset="utf-8" />
    <title></title>
  </head>
  <body>
  <div><a href="./addUser">新增用户</a></div>
  <table border="1" width="100%" cellpadding="0" cellspacing="0">
    <tr>
      <th>姓名</th>
      <th>年纪</th>
      <th>操作</td>
    </tr>
    {{each docs}}
    <tr align="center">
      <td>
      {{$value.name}}
      </td>
      <td>
        {{$value.age}}
      </td>
      <td>
        <span><a href="/edit?id={{@ $value._id}}">修改</a></span>
        <span><a href="/del?id={{@ $value._id}}">删除</a></span>
      </td>
      {{/each}}
    </tr>
  </table>
  </body>
  <script>


  </script>
</html>

• edit.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta http-equiv="X-UA-Compatible" content="ie=edge" />
    <title>Document</title>
  </head>
  <body>
    <p>编辑用户</p>
    <form action="/doEdit" method="post" id="form">
      <input type="hidden" name="_id" value="{{@ docs._id}}" />
      <p>用户名：<input type="text" name="name" value="{{docs.name}}" /></p>
      <p>年纪：<input type="text" name="age" value="{{docs.age}}" /></p>
      <p><input type="submit" value="提交" /></p>
    </form>
  </body>
</html>

• addUser.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta http-equiv="X-UA-Compatible" content="ie=edge" />
    <title>Document</title>
  </head>
  <body>
    <h1>新增用户</h1>
    <form action="/add" method="post" id="form">
      <p>用户名：<input type="text" name="name" /></p>
      <p>年纪：<input type="text" name="age" /></p>
      <p><input type="submit" value="提交" /></p>
    </form>
  </body>
</html>