var connection = mysql.createConnection({ host: "localhost", user: "root", password: "", database: "vuestu", port: 3306 });
时间: 2023-07-19 17:49:38 浏览: 33
这是一个使用MySQL模块创建数据库连接的代码片段,其中var关键字表示声明变量,connection表示创建连接对象,mysql表示导入MySQL模块,createConnection()方法表示创建数据库连接。在Node.js中,可以使用MySQL模块来连接MySQL数据库,并执行查询和其他操作。在创建数据库连接时,需要传入一个包含连接参数的JavaScript对象,其中包括host、user、password、database和port等属性。通过使用createConnection()方法创建连接对象,可以方便地对数据库进行操作。在连接数据库后,可以使用connection.query()方法来执行SQL查询和更新操作。执行完毕后,应该使用connection.end()方法关闭数据库连接,以释放资源。
相关问题
替换为学生管理系统const express=require('express'); const mysql = require("mysql"); const app = express() const parser = require('body-parser') var jsonParser = parser.json(); app.use(jsonParser) const cors = require("cors"); app.use(cors()); app.post('/axios',(request,res,next)=>{ username=request.body.username.trim() password=request.body.password const connection = mysql.createConnection({ host:"localhost", user:"root", password:"123456", database:"my_db_01", port:3306 }) //数据库信息 connection.connect(); connection.query("select * from users where userName=? ",[username],(err,results,fields)=>{ if(err) throw err; if(results.length >0){ let str = JSON.stringify(results);//对对你进行字符串转换 next() const data={name:'axios'} console.log(results.length) //发送响应体 res.end("1"); } }) //连接数据库 connection.query('insert into users(username,password) value (?,?)',[username,password],(err,results,fields)=>{ if(err) { return(console.log(err.message)); } if(results.affectedRows==1){ //发送响应体 res.end('0') } }) connection.end(); }); app.listen(8080,()=>{ console.log("http://127.0.0.1:8080 has started ..."); });
这段代码是一个使用 Express 和 MySQL 实现的学生管理系统,其中包括了注册和登录功能。
代码解析如下:
1. 引入依赖:
```javascript
const express = require('express');
const mysql = require("mysql");
const parser = require('body-parser');
const cors = require("cors");
const app = express();
const jsonParser = parser.json();
app.use(jsonParser);
app.use(cors());
```
2. 处理 POST 请求:
```javascript
app.post('/axios', (request, res, next) => {
username = request.body.username.trim();
password = request.body.password;
const connection = mysql.createConnection({
host: "localhost",
user: "root",
password: "123456",
database: "my_db_01",
port: 3306
});
// 查询用户是否存在
connection.connect();
connection.query("SELECT * FROM users WHERE username = ?", [username], (err, results, fields) => {
if (err) throw err;
if (results.length > 0) {
let str = JSON.stringify(results);
next();
const data = { name: 'axios' };
console.log(results.length);
res.end("1");
}
});
// 注册用户
connection.query('INSERT INTO users(username, password) VALUES (?, ?)', [username, password], (err, results, fields) => {
if (err) {
return(console.log(err.message));
}
if (results.affectedRows == 1) {
res.end('0');
}
});
connection.end();
});
```
3. 启动服务器:
```javascript
app.listen(8080, () => {
console.log("http://127.0.0.1:8080 has started ...");
});
```
var fs = require('fs'); var ejs = require('ejs'); var mysql = require('mysql'); var express = require('express'); var bodyParser = require('body-parser'); // 连接mysql数据库 var client = mysql.createConnection({ host: 'localhost', port:"3306", user: 'root', password: 'root123', database: 'my_db_1' }); // //判断是否连接成功 client.connect(function(err){ if(err){ console.log('[query] - :'+err); return; } console.log('[connection connect] Mysql数据库连接成功!'); }); // 解析请求体中的URL的编码数据 var app = express(); app.use(bodyParser.urlencoded({ extended: false })); // app.listen(52273, function () { console.log('服务器运行在 http://127.0.0.1:52273'); }); // app.get('/', function (request, response) { // fs.readFile('book-list.html', 'utf8', function (error, data) { // client.query('SELECT * FROM books', function (error, results) { // response.send(ejs.render(data, { data: results })); }); }); }); // app.get('/delete/:id', function (request, response) { // client.query('DELETE FROM books WHERE id=?', [request.params.id], function () { // response.redirect('/'); }); }); // app.get('/insert', function (request, response) { // fs.readFile('book-insert.html', 'utf8', function (error, data) { // response.send(data); }); }); // app.post('/insert', function (request, response) { // var body = request.body; // client.query('INSERT INTO books (bookname, author, press) VALUES (?, ?, ?)', [ body.bookname, body.author, body.press ], function () { // response.redirect('/'); }); }); // app.get('/edit/:id', function (request, response) { // fs.readFile('book-edit.html', 'utf8', function (error, data) { // client.query('SELECT * FROM books WHERE id = ?', [ request.params.id ], function (error, result) { // response.send(ejs.render(data, { data: result[0] })); }); }); }); // app.post('/edit/:id', function (request, response) { // var body = request.body; // client.query('UPDATE books SET bookname=?, author=?, press=? WHERE id=?', [body.bookname, body.author, body.press, request.params.id], function () { // response.redirect('/'); }); });补全注释
这段代码是一个使用Node.js搭建的服务器,主要功能是连接MySQL数据库,并通过Express框架提供HTTP服务。以下是代码注释的补全:
```javascript
var fs = require('fs');
var ejs = require('ejs');
var mysql = require('mysql');
var express = require('express');
var bodyParser = require('body-parser');
// 连接mysql数据库
var client = mysql.createConnection({
host: 'localhost',
port:"3306",
user: 'root',
password: 'root123',
database: 'my_db_1'
});
// 判断是否连接成功
client.connect(function(err){
if(err){
console.log('[query] - :' + err);
return;
}
console.log('[connection connect] Mysql数据库连接成功!');
});
// 解析请求体中的URL的编码数据
var app = express();
app.use(bodyParser.urlencoded({
extended: false
}));
// 启动服务器
app.listen(52273, function () {
console.log('服务器运行在 http://127.0.0.1:52273');
});
// 处理根路径的GET请求
app.get('/', function (request, response) {
fs.readFile('book-list.html', 'utf8', function (error, data) {
// 查询数据库并将结果渲染到模板中
client.query('SELECT * FROM books', function (error, results) {
response.send(ejs.render(data, {
data: results
}));
});
});
});
// 处理删除图书的GET请求
app.get('/delete/:id', function (request, response) {
client.query('DELETE FROM books WHERE id=?', [request.params.id], function () {
response.redirect('/');
});
});
// 处理插入图书的GET请求
app.get('/insert', function (request, response) {
fs.readFile('book-insert.html', 'utf8', function (error, data) {
response.send(data);
});
});
// 处理插入图书的POST请求
app.post('/insert', function (request, response) {
var body = request.body;
client.query('INSERT INTO books (bookname, author, press) VALUES (?, ?, ?)', [
body.bookname, body.author, body.press
], function () {
response.redirect('/');
});
});
// 处理编辑图书的GET请求
app.get('/edit/:id', function (request, response) {
fs.readFile('book-edit.html', 'utf8', function (error, data) {
client.query('SELECT * FROM books WHERE id = ?', [
request.params.id
], function (error, result) {
response.send(ejs.render(data, {
data: result[0]
}));
});
});
});
// 处理编辑图书的POST请求
app.post('/edit/:id', function (request, response) {
var body = request.body;
client.query('UPDATE books SET bookname=?, author=?, press=? WHERE id=?', [
body.bookname, body.author, body.press, request.params.id
], function () {
response.redirect('/');
});
});
```
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