netty实现http服务器
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2024-03-20 16:31:22
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0 概述
HTTP(超文本传输协议)是建立在TCP传输协议之上的应用层协议,由于其简单、灵活,其应用也非常之广泛。本文主要讲解如何用Netty 实现一个简单的http服务器。
1 http 请求消息
Http的请求由三部分组成:请求行、消息头、请求正文(body)。
请求行以一个方法开头,以空格分开,后面跟着请求URI和协议版本,格式为:Method(方法) Request-URI (统一资源标识符) HTTP-version(请求版本) CRLF(换行符)。
GET / HTTP/1.1
POST / HTTP/1.1
请求方法有多种,各种方法如下:
- GET 请求获取Request-URI 所标识的资源。
- POST 在Request-URI 所标识的资源后附加新的提交数据
- HEAD 请求获取由Request-URI 所标识的资源相应消息报头
- PUT 请求服务器存储一个资源,并用Request-URI作为其标识。
- DELETE 请求服务器删除Request-URI 所标识的资源。
- TRACE:请求服务器回收到的请求信息,主要用于测试或者诊断
- CONNECT 保留将来使用
- OPTIONS 请求查询服务器性能或者查询与资源相关的选项需求。
下面是一个http 请求消息(没有请求正文),请求行后面都是请求头。
GET / HTTP/1.1
Host: 127.0.0.1:8080
Connection: keep-alive
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/61.0.3163.100 Safari/537.36
Upgrade-Insecure-Requests: 1
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8
Accept-Encoding: gzip, deflate, br
Accept-Language: zh-CN,zh;q=0.8
2 http 响应消息
HTPP响应消息也是由3部分组成,分别是:状态行、消息报头、响应正文。
状态行的格式为: HTTP-version Status-Code Reason-Phrase CRLF.
具体如下
HTTP/1.1 200 OK
HTTP/1.1 404 Not Found
状态码由三位数字组成,第一个数字表示响应类别,有五种可能取值。
- 1xx:指示信息。表示请求已经接受,继续处理。
- 2xx :成功。表示请求已经被成功接收,理解、接受
- 3xx :重定向。要完成请求必须进行进一步的操作。
- 4xx:客户端错误,请求有语法错误,或者请求无法完成。
- 5xx:服务器错误。服务器未能处理。
3 netty 实现http服务器
服务端实现
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.http.HttpRequestDecoder;
import io.netty.handler.codec.http.HttpServerCodec;
/**
* Created by apple on 17/10/21.
*/
public class HttpServer {
public static void start(final int port) throws Exception {
EventLoopGroup boss = new NioEventLoopGroup();
EventLoopGroup woker = new NioEventLoopGroup();
ServerBootstrap serverBootstrap = new ServerBootstrap();
try {
serverBootstrap.channel(NioServerSocketChannel.class)
.group(boss, woker)
.childOption(ChannelOption.SO_KEEPALIVE, true)
.option(ChannelOption.SO_BACKLOG, 1024)
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ch.pipeline().addLast("http-decoder",new HttpServerCodec());
ch.pipeline().addLast(new HttpServerHandler());
}
});
ChannelFuture future = serverBootstrap.bind(port).sync();
future.channel().closeFuture().sync();
} finally {
boss.shutdownGracefully();
woker.shutdownGracefully();
}
}
public static void main(String[] args) throws Exception {
start(8080);
}
}
HttpServerHandler 类
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.handler.codec.http.*;
import java.util.HashMap;
import java.util.Map;
/**
* Created by apple on 17/10/21.
*/
public class HttpServerHandler extends ChannelInboundHandlerAdapter {
private String content = "hello world";
private final static String LOC = "302";
private final static String NOT_FOND = "404";
private final static String BAD_REQUEST = "400";
private final static String INTERNAL_SERVER_ERROR = "500";
private static Map<String, HttpResponseStatus> mapStatus = new HashMap<String, HttpResponseStatus>();
static {
mapStatus.put(LOC, HttpResponseStatus.FOUND);
mapStatus.put(NOT_FOND, HttpResponseStatus.NOT_FOUND);
mapStatus.put(BAD_REQUEST, HttpResponseStatus.BAD_REQUEST);
mapStatus.put(INTERNAL_SERVER_ERROR, HttpResponseStatus.INTERNAL_SERVER_ERROR);
}
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
if (msg instanceof HttpRequest) {
HttpRequest request = (HttpRequest) msg;
boolean keepaLive = HttpUtil.isKeepAlive(request);
System.out.println("method" + request.method());
System.out.println("uri" + request.uri());
String uri = request.uri().replace("/", "").trim();
FullHttpResponse httpResponse = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK);
if (mapStatus.get(uri) != null) {
httpResponse.setStatus(mapStatus.get(uri));
httpResponse.content().writeBytes(mapStatus.get(uri).toString().getBytes());
} else {
httpResponse.content().writeBytes(content.getBytes());
}
//重定向处理
if (httpResponse.status().equals(HttpResponseStatus.FOUND)) {
httpResponse.headers().set(HttpHeaderNames.LOCATION, "https://www.baidu.com/");
}
httpResponse.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/html;charset=UTF-8");
httpResponse.headers().setInt(HttpHeaderNames.CONTENT_LENGTH, httpResponse.content().readableBytes());
if (keepaLive) {
httpResponse.headers().set(HttpHeaderNames.CONNECTION, HttpHeaderValues.KEEP_ALIVE);
ctx.writeAndFlush(httpResponse);
} else {
ctx.writeAndFlush(httpResponse).addListener(ChannelFutureListener.CLOSE);
}
}
}
}
启动服务后,可以通过浏览器测试如下
http://127.0.0.1:8080/302