JavaSocket利用Socket自己实现HTTP协议
小奥利用Socket动手实现简单HTTP协议
一、实现
我们知道HTTP协议是在应用层解析内容的,所以我们只需要按照它的报文格式封装和解析数据即可。
关于具体的传输协议,使用的还是Socket,关于Socket,可以移步这篇文章:Java中的Socket你了解吗
这里我将带领大家使用NioServer实现一个简单的HTTP协议,注意,这里主要是出于了解HTTP协议是如何实现的,而不是真正实现一个HTTP协议。
因为HTTP协议是在接收到数据之后才会用到的,所以,我们只需要在Handler处理方法中实现就可以了。
我们首先来看一下效果。
当我们启动程序,然后在浏览器中输入http://localhost:8080/
发起请求,这时控制台会打印如下信息:
GET / HTTP/1.1 Host: localhost:8080 Connection: keep-alive Cache-Control: max-age=0 sec-ch-ua: "Not_A Brand";v="8", "Chromium";v="120", "Google Chrome";v="120" sec-ch-ua-mobile: ?0 sec-ch-ua-platform: "Windows" Upgrade-Insecure-Requests: 1 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*
*;q=0.8 Sec-Fetch-Site: same-origin Sec-Fetch-Mode: no-cors Sec-Fetch-Dest: image Referer: http: Accept-Encoding: gzip, deflate, br Accept-Language: zh-CN,zh;q=0.9
Method: GET url: /favicon.ico HTTP Version: HTTP/1.1
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浏览器显示结果如图所示:
这里只是一个简单的示例,目的是让大家了解HTTP协议中的实现方法,功能不够完善,而且也不能实现请求的处理。
对于了解HTTP协议实现的方法,个人觉得还是有必要看看的。
二、完整代码
思路:
整个过程非常简单,我们只需要按照报文的格式来读取和发送就可以了。
- 接收到数据后按
\r\n
分割成每一行,空行前面都是报文头;
- 空行下面如果有内容就是报文主体,注意,Get请求没有报文主体;
完整代码如下:
import java.io.IOException; import java.net.InetSocketAddress; import java.nio.ByteBuffer; import java.nio.channels.SelectionKey; import java.nio.channels.Selector; import java.nio.channels.ServerSocketChannel; import java.nio.channels.SocketChannel; import java.nio.charset.Charset; import java.util.Iterator;
public class NioServer { public static void main(String[] args) throws Exception { ServerSocketChannel ssc = ServerSocketChannel.open(); ssc.socket().bind(new InetSocketAddress(8080)); ssc.configureBlocking(false); Selector selector = Selector.open(); ssc.register(selector, SelectionKey.OP_ACCEPT); while (true) { if (selector.select(3000) == 0) { continue; }
Iterator<SelectionKey> keyIterator = selector.selectedKeys().iterator(); while (keyIterator.hasNext()) { SelectionKey key = keyIterator.next(); new Thread(new HttpHandler(key)).run(); keyIterator.remove(); } } }
private static class HttpHandler implements Runnable { private int bufferSize = 1024; private String localCharset = "UTF-8"; private SelectionKey key;
public HttpHandler(SelectionKey key) { this.key = key; }
public void handleAccept() throws IOException { SocketChannel sc = ((ServerSocketChannel) key.channel()).accept(); sc.configureBlocking(false); sc.register(key.selector(), SelectionKey.OP_READ, ByteBuffer.allocate(bufferSize)); }
public void handleRead() throws IOException { SocketChannel sc = (SocketChannel) key.channel(); ByteBuffer buffer = (ByteBuffer) key.attachment(); buffer.clear(); if (sc.read(buffer) == -1) { sc.close(); } else { buffer.flip(); String receivedString = Charset.forName(localCharset).newDecoder().decode(buffer).toString(); String[] requsetMessage = receivedString.split("\r\n"); for (String s : requsetMessage) { System.out.println(s); if (s.isEmpty()) { break; } } String[] firstLine = requsetMessage[0].split(" "); System.out.println(); System.out.println("Method:\t" + firstLine[0]); System.out.println("url:\t" + firstLine[1]); System.out.println("HTTP Version:\t" + firstLine[2]); System.out.println();
StringBuffer sendString = new StringBuffer(); sendString.append("HTTP/1.1 200 OK\r\n"); sendString.append("Content-Type:text/html;charset=" + localCharset + "\r\n"); sendString.append("\r\n");
sendString.append("<html><head><title>显示报文</title></head></body>"); sendString.append("接收到的请求报文是:<br/>"); for (String s : requsetMessage) { sendString.append(s + "<br/>"); } sendString.append("</body></html>"); buffer = ByteBuffer.wrap(sendString.toString().getBytes(localCharset)); sc.write(buffer); sc.close(); } }
@Override public void run() { try { if (key.isAcceptable()) { handleAccept(); } if (key.isReadable()) { handleRead(); } } catch (IOException e) { e.printStackTrace(); } } } }
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