Node.js（六）MongoDB

student.js

var express = require('express');
var router = express.Router();
const _=require("lodash");
const { MongoClient } = require("mongodb");  //依赖MongoClient
var client=new MongoClient("mongodb://127.0.0.1:27017");  //实例化一个客户端
var clientAdd=new MongoClient("mongodb://127.0.0.1:27017");  //实例化一个客户端
var clientdel=new MongoClient("mongodb://127.0.0.1:27017");  //实例化一个客户端
var books=[];

//查询全部
async function run(){
  try{
      let db=await client.db("BookMessge"); //获取数据库
      let students=await db.collection("books");  //获取集合
      let cursor=await students.find();  //执行查询并返回游标对象

      await cursor.forEach(data=>books.push(data));  //遍历游标，取出数据
  }
  finally{
      await client.close();  //关闭
  }
};

//添加
async function add(booklist){
  try{
      let db=await clientAdd.db("BookMessge");  //获取数据库
      let students=await db.collection("books");  //获取集合，表
      let result=await students.insertOne(booklist);  //执行向数据库中添加数据并等待响应结果
      console.log(result);
  }
  finally{
      await clientAdd.close();  //关闭数据库
  }
}

//删除
async function del(id){
  try{
      let db=await clientdel.db("BookMessge");  //获取数据库
      let students=await db.collection("books");  //获取集合，表
      let result= await students.deleteOne(id);  //执行删除
      console.log(result);
  }
  finally{
      await clientdel.close();  //关闭
  }
}

run().catch(console.log);

/* GET home page. */
router.get('/', function(req, res, next) {
  res.render('student', {books,msg: '',stu:{id:"",name:"",age:""}});
});

router.get('/delete/:id', function(req, res, next) {
  //查找选中id的索引
  let id=req.params.id;
  console.log(id);
  let ids={id:""};
  ids.id=id;
  console.log(ids);
  del(ids).catch(console.log);
  res.render('student', {books,msg: '删除成功！',stu:{id:"",name:"",age:""}});
});

//添加
router.post('/add', function(req, res, next) {
  //查找选中id的索引
  let book=req.body;
  //根据编号排序
  let new_id=_.orderBy(books,parseInt(["id"]));
  book.id=_.last(new_id).id+1;
  //拿到序号
  let newbooks_id=_.orderBy(books,parseInt(["books_id"]));
  book.books_id=_.last(newbooks_id).books_id+1;
  console.log(book);
  add(book).catch(console.log);
  res.render('student', {books,msg: '添加成功'});
});

//修改
router.get('/edit/:id', function(req, res, next) {
  //查找选中id的索引
  let stu=_.find(stus,{id:parseInt(req.params.id)})
  console.log(stus);
  res.render('student', {stus,msg: '',stu});
});


//更新
router.post('/update', function(req, res, next) {
  //查找选中id的索引
  let stuSubmit=req.body;
  let stu=_.find(stus,{id:parseInt(stuSubmit.id)})
  stu.name=stuSubmit.name;
  stu.age=stuSubmit.age;
  //重新渲染页面
  res.render('student', {stus,msg: '更新成功',stu:{id:"",name:"",age:""}});
});

module.exports = router;

student.ejs

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>图书管理系统</title>
</head>
<body>
    <h1>图书管理系统</h1>
    <table width="100%" border="1">
        <tr>
            <th>序号</th>
            <th>编号</th>
            <th>书名</th>
            <th>封面</th>
            <th>价格</th>
            <th>作者</th>
            <th>操作</th>
        </tr>
        <% for(let i=0;i<books.length;i++){ %>
            <tr style="text-align: center;">
                <td><%=books[i].id%></td>
                <td><%=books[i].books_id%></td>
                <td><%=books[i].name%></td>
                <td><%=books[i].img%></td>
                <td><%=books[i].price%></td>
                <td><%=books[i].author%></td>
                <td>
                    <a href="/delete/<%=books[i].id%>" class="del">删除</a>
                    <a href="/edit/<%=books[i].id%>">修改</a>
                </td>
            </tr>
        <%} %>
    </table>
    <fieldset>
        <legend>添加学生</legend>
        <form method="post">
            <input type="hidden" name="id" id="id" value="<%=books.id%>">
            <input type="hidden" name="books_id" id="books_id" value="<%=books.books_id%>">
            <p>
                <label>图书名称：</label>
                <input type="text" name="name" value="<%=books.name%>">
            </p>
            <p>
                <label>图书封面：</label>
                <input type="file" name="img" value="<%=books.img%>">
            </p>
            <p>
                <label>图书价格：</label>
                <input type="text" name="price" value="<%=books.price%>">
            </p>
            <p>
                <label>图书作者：</label>
                <input type="text" name="author" value="<%=books.author%>">
            </p>
            <button formaction="/add">添加</button>
            <button formaction="/update">更新</button>
        </form>
    </fieldset>

    <h4><%=msg%></h4>

    <script>
      let dels=document.querySelectorAll(".del");
      for(let i=0;i<dels.length;i++){
        dels[i].onclick=function(){
            return confirm("您确定要删除吗？");
        }
      }
    </script>
</body>
</html>

app.js

var createError = require('http-errors');
var express = require('express');
var path = require('path');
var cookieParser = require('cookie-parser');
var logger = require('morgan');

var indexRouter = require('./routes/index');
var usersRouter = require('./routes/users');
var studentRouter = require('./routes/student');


var app = express();

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'ejs');

app.use(logger('dev'));
app.use(express.json());
app.use(express.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));

app.use('/index', indexRouter);
app.use('/users', usersRouter);
app.use('/', studentRouter);

// catch 404 and forward to error handler
app.use(function(req, res, next) {
  next(createError(404));
});

// error handler
app.use(function(err, req, res, next) {
  // set locals, only providing error in development
  res.locals.message = err.message;
  res.locals.error = req.app.get('env') === 'development' ? err : {};

  // render the error page
  res.status(err.status || 500);
  res.render('error');
});

module.exports = app;

posted on 2022-09-21 08:53 最帅爸爸阅读(34) 评论(0) 收藏举报