Node.js是一个基于Chrome V8引擎的JavaScript运行环境，它使得JavaScript可以在服务器端运行。以下是一些在Node.js中常见的操作和相应的代码示例：
- 文件系统操作：
const fs = require('fs');
// 异步读取
fs.readFile('example.txt', 'utf8', (err, data) => {
if (err) throw err;
console.log(data);
});
// 同步读取
let data = fs.readFileSync('example.txt', 'utf8');
console.log(data);
// 异步写入
fs.writeFile('example.txt', 'Hello World!', (err) => {
if (err) throw err;
console.log('The file has been saved!');
});
// 同步写入
fs.writeFileSync('example.txt', 'Hello World!');
// 删除文件
fs.unlink('example.txt', (err) => {
if (err) throw err;
console.log('File deleted successfully');
});
- 创建HTTP服务器：
const http = require('http');
const server = http.createServer((req, res) => {
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('Hello World\n');
});
const port = 3000;
server.listen(port, () => {
console.log(`Server running at http://localhost:${port}/`);
});
- 使用Express框架创建Web应用：
const express = require('express');
const app = express();
app.get('/', (req, res) => {
res.send('Hello World!');
});
app.listen(3000, () => {
console.log('Server running on port 3000');
});
- 使用Node.js处理网络请求：
const http = require('http');
http.get('http://example.com', (resp) => {
let data = '';
// 接收数据片段
resp.on('data', (chunk) => {
data += chunk;
});
// 数据接收完毕
resp.on('end', () => {
console.log(data);
});
}).on("error", (err) => {
console.log("Error: " + err.message);
});
- 使用Node.js创建TCP服务器：
const net = require('net');
const server = net.createServer((socket) => {
console.log('A client connected');
socket.on('data', (data) => {
console.log(data.toString());
socket.write('Hello Client!');
});
socket.on('close', () => {
console.log('A client disconnected');
});
});
server.listen(1337, () => {
console.log('Server listening on 1337');
});
- 使用Node.js创建TCP客户端：
const net = require('net');
const client = net.createConnection({port: 1337, host: 'localhost'}, () => {
console.log('Connected to server!');
});
client.on('data', (data) => {
console.log(data.toString());
client.end();
});
client.on('close', () => {
console.log('Connect