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;
标签：Node,MongoDB,app,js,books,let,res,var,id From： https://www.cnblogs.com/zsbb/p/16714368.html