Java基于Netty实现Http server的实战
目录
- HTTP协议基础知识
- Netty的http协议栈
- 基于Netty实现httpserver
HTTP协议基础知识
HTTP(超文本传输协议,英文:HyperText Transfer Protocol,缩写:HTTP)是基于TCP/IP协议的应用层的协议,常用于分布式、协作式和超媒体信息系统的应用层协议。
http协议的主要特点:
(1)支持CS(客户端/服务器)模式。
(2)使用简单,指定URL并携带必要的参数即可。
(3)灵活。传输非常多类型的数据对象,通过Content-Type指定即可。
(4)无状态。
我们日常浏览器输入一个url,请求服务器就是用的http协议,url的格式如下:
http请求体的组成:
- 方法
- uri
- http版本
- 参数
请求方法:
- 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数据
- HEAD 请求获取由Request-URI所标识的资源的响应消息报头
- 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 请求服务器回送收到的请求信息,主要用于测试或诊断
- CONNECT 保留将来使用
- OPTIONS 请求查询服务器的性能,或者查询与资源相关的选项和需求
响应状态码:
- 1xx Informational
- 2xx Success
- 3xx Redirection
- 4xx Client Error
- 5xx Server Error
HTTP 1 VS HTTP 2:
http 1不支持长连接,每次请求建立连接,响应后就关闭连接。HTTP2支持长连接,连接复用。
Netty的http协议栈
netty提供了对http/https协议的支持,我们可以基于netty很容易写出http应用程序。
(1)编解码
- HttpRequestEncoder 对 HTTP 请求进行编码,用于客户端出参
- HttpResponseEncoder 对 HTTP 响应进行编码,用于服务端出参
- HttpRequestDecoder 对 HTTP 请求进行解码,用于服务端入参处理
- HttpResponseDecoder 对 HTTP 响应进行解码,用于客户端对响应结果解析解析
(2)请求体FullHttpRequest和响应体FullHttpResponse
FullHttpRequest
- HttpRequest:请求头信息对象;
- HttpContent:请求正文对象,一个 FullHttpRequest 中可以包含多个 HttpContent;
- LastHttpContent:标记请求正文的结束,可能会包含请求头的尾部信息;
FullHttpResponse
- HttpResponse:响应头信息对象;
- HttpContent:响应正文对象,一个 FullHttpResponse 中可以包含多个 HttpContent;
- LastHttpContent:标记响应正文的结束,可能会包含响应头的尾部信息;
(3)HttpObjectAggregator-http消息聚合器
http的post请求包含3部分:
- request line(method、uri、protocol version)
- header
- body
HttpObjectAggregator能够把多个部分整合在一个java对象中(另外消息体比较大的时候,还可能会分成多个消息,都会被聚合成一个整体对象),方便使用。
基于Netty实现http server
整体架构设计:
核心类SimpleHttpServer:
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.HttpObjectAggregator; import io.netty.handler.codec.http.HttpRequestDecoder; import io.netty.handler.codec.http.HttpResponseEncoder; import lombok.extern.slf4j.Slf4j; /** * http server based netty * * @author summer * @version $Id: SimpleHttpServer.java, v 0.1 2022年01月26日 9:34 AM summer Exp $ */ @Slf4j public class SimpleHttpServer { /** * host */ private final static String host = "127.0.0.1"; /** * 端口号 */ private final static Integer port = 8085; /** * netty服务端启动方法 */ public void start() { log.info("SimpleHttpServer start begin "); EventLoopGroup bossEventLoopGroup = new NioEventLoopGroup(1); EventLoopGroup workerEventLoopGroup = new NioEventLoopGroup(); try { ServerBootstrap serverBootstrap = new ServerBootstrap() .group(bossEventLoopGroup, workerEventLoopGroup) .channel(NioServerSocketChannel.class) //开启tcp nagle算法 .childOption(ChannelOption.TCP_NODELAY, true) //开启长连接 .childOption(ChannelOption.SO_KEEPALIVE, true) .childHandler(new ChannelInitializer<SocketChannel>() { @Override protected void initChannel(SocketChannel c) { c.pipeline().addLast(new HttpRequestDecoder()) .addLast(new HttpResponseEncoder()) .addLast(new HttpObjectAggregator(512 * 1024)) .addLast(new SimpleHttpServerHandler()); } }); ChannelFuture channelFuture = serverBootstrap.bind(host, port).sync(); log.info("SimpleHttpServer start at port " + port); channelFuture.channel().closeFuture().sync(); } catch (Exception e) { log.error("SimpleHttpServer start exception,", e); } finally { log.info("SimpleHttpServer shutdown bossEventLoopGroup&workerEventLoopGroup gracefully"); bossEventLoopGroup.shutdownGracefully(); workerEventLoopGroup.shutdownGracefully(); } } }
实际处理请求的netty handler是SimpleHttpServerHandler:
import com.alibaba.fastjson.JSON; import io.netty.buffer.Unpooled; import io.netty.channel.ChannelFutureListener; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.SimpleChannelInboundHandler; import io.netty.handler.codec.http.*; import lombok.extern.slf4j.Slf4j; import java.nio.charset.StandardCharsets; import java.util.List; import java.util.Map; /** * http服务端处理handler实现 * * @author summer * @version $Id: SimpleHttpServerHandler.java, v 0.1 2022年01月26日 9:44 AM summer Exp $ */ @Slf4j public class SimpleHttpServerHandler extends SimpleChannelInboundHandler<FullHttpRequest> { @Override protected void channelRead0(ChannelHandlerContext ctx, FullHttpRequest fullHttpRequest) { try { log.info("SimpleHttpServerHandler receive fullHttpRequest=" + fullHttpRequest); String result = doHandle(fullHttpRequest); log.info("SimpleHttpServerHandler,result=" + result); byte[] responseBytes = result.getBytes(StandardCharsets.UTF_8); FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_0, HttpResponseStatus.OK, Unpooled.wrappedBuffer(responseBytes)); response.headers().set("Content-Type", "text/html; charset=utf-8"); response.headers().setInt("Content-Length", response.content().readableBytes()); boolean isKeepAlive = HttpUtil.isKeepAlive(response); if (!isKeepAlive) { ctx.write(response).addListener(ChannelFutureListener.CLOSE); } else { response.headers().set("Connection", "keep-alive"); ctx.write(response); } } catch (Exception e) { log.error("channelRead0 exception,", e); } } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) { cause.printStackTrace(); ctx.close(); } @Override public void channelReadComplete(ChannelHandlerContext ctx) { ctx.flush(); } /** * 实际处理 * * @param fullHttpRequest HTTP请求参数 * @return */ private String doHandle(FullHttpRequest fullHttpRequest) { if (HttpMethod.GET == fullHttpRequest.method()) { QueryStringDecoder queryStringDecoder = new QueryStringDecoder(fullHttpRequest.uri()); Map<String, List<String>> params = queryStringDecoder.parameters(); return JSON.toJSONString(params); } else if (HttpMethod.POST == fullHttpRequest.method()) { return fullHttpRequest.content().toString(); } return ""; } }
在主线程中启动服务端:
import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplication public class SimplehttpserverApplication { public static void main(String[] args) { SimpleHttpServer simpleHttpServer = new SimpleHttpServer(); simpleHttpServer.start(); SpringApplication.run(SimplehttpserverApplication.class, args); } }
启动成功:
利用postman工具发起http请求进行测试,这里简单测试get请求:
http://127.0.0.1:8085/?name=name1&value=v2
服务端日志也打印出了处理情况,处理正常:
19:24:59.629 [nioEventLoopGroup-3-3] INFO com.summer.simplehttpserver.SimpleHttpServerHandler - SimpleHttpServerHandler receive fullHttpRequest=HttpObjectAggregator$AggregatedFullHttpRequest(decodeResult: success, version: HTTP/1.1, content: CompositeByteBuf(ridx: 0, widx: 0, cap: 0, components=0))
GET /?name=name1&value=v2 HTTP/1.1
User-Agent: PostmanRuntime/7.26.8
Accept: */*
Cache-Control: no-cache
Postman-Token: 7dda7e2d-6f76-4008-8b74-c2b7d78f4b2e
Host: 127.0.0.1:8085
Accept-Encoding: gzip, deflate, br
Connection: keep-alive
content-length: 0
19:24:59.629 [nioEventLoopGroup-3-3] INFO com.summer.simplehttpserver.SimpleHttpServerHandler - SimpleHttpServerHandler,result={"name":["name1"],"value":["v2"]}
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