基于Netty4的HttpServer和HttpClient的简单实现

Netty的主页：http://netty.io/index.html

使用的Netty的版本：netty-4.0.23.Final.tar.bz2 ‐ 15-Aug-2014 (Stable, Recommended)

Http 消息格式：

Http request:

Method path-to-resource HTTPVersion-number

Header-name-1: value1

Header-name-2: value2



Optional request body

Http response:

HTTP/Version-number response-code response-phrase 

Header-name-1: value1

Header-name-2: value2



Optional response body

实现一个简单的Http请求及响应过程：

1、Client向Server发送http请求。

2、Server端对http请求进行解析。

3、Server端向client发送http响应。

4、Client对http响应进行解析。

Netty中Http request消息格式：

Netty中Http response消息格式：

代码实例：

Http Server：

package com.netty.test;



import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;



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.HttpResponseEncoder; 



public class HttpServer {



    private static Log log = LogFactory.getLog(HttpServer.class);

    

    public void start(int port) throws Exception {

        EventLoopGroup bossGroup = new NioEventLoopGroup();

        EventLoopGroup workerGroup = new NioEventLoopGroup();

        try {

            ServerBootstrap b = new ServerBootstrap();

            b.group(bossGroup, workerGroup).channel(NioServerSocketChannel.class)

                    .childHandler(new ChannelInitializer<SocketChannel>() {

                                @Override

                                public void initChannel(SocketChannel ch) throws Exception {

                                    // server端发送的是httpResponse，所以要使用HttpResponseEncoder进行编码

                                    ch.pipeline().addLast(new HttpResponseEncoder());

                                    // server端接收到的是httpRequest，所以要使用HttpRequestDecoder进行解码

                                    ch.pipeline().addLast(new HttpRequestDecoder());

                                    ch.pipeline().addLast(new HttpServerInboundHandler());

                                }

                            }).option(ChannelOption.SO_BACKLOG, 128) 

                    .childOption(ChannelOption.SO_KEEPALIVE, true);



            ChannelFuture f = b.bind(port).sync();



            f.channel().closeFuture().sync();

        } finally {

            workerGroup.shutdownGracefully();

            bossGroup.shutdownGracefully();

        }

    }



    public static void main(String[] args) throws Exception {

        HttpServer server = new HttpServer();

        log.info("Http Server listening on 8844 ...");

        server.start(8844);

    }

}

响应请求的HttpServerInboundHandler：

package com.netty.test;



import static io.netty.handler.codec.http.HttpHeaders.Names.CONNECTION;

import static io.netty.handler.codec.http.HttpHeaders.Names.CONTENT_LENGTH;

import static io.netty.handler.codec.http.HttpHeaders.Names.CONTENT_TYPE;

import static io.netty.handler.codec.http.HttpResponseStatus.OK;

import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1;



import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;



import io.netty.buffer.ByteBuf;

import io.netty.buffer.Unpooled;

import io.netty.channel.ChannelHandlerContext;

import io.netty.channel.ChannelInboundHandlerAdapter;

import io.netty.handler.codec.http.DefaultFullHttpResponse;

import io.netty.handler.codec.http.FullHttpResponse;

import io.netty.handler.codec.http.HttpContent;

import io.netty.handler.codec.http.HttpHeaders;

import io.netty.handler.codec.http.HttpHeaders.Values;

import io.netty.handler.codec.http.HttpRequest;



public class HttpServerInboundHandler extends ChannelInboundHandlerAdapter {



    private static Log log = LogFactory.getLog(HttpServerInboundHandler.class);



    private HttpRequest request;



    @Override

    public void channelRead(ChannelHandlerContext ctx, Object msg)

            throws Exception {

        if (msg instanceof HttpRequest) {

            request = (HttpRequest) msg;



            String uri = request.getUri();

            System.out.println("Uri:" + uri);

        }

        if (msg instanceof HttpContent) {

            HttpContent content = (HttpContent) msg;

            ByteBuf buf = content.content();

            System.out.println(buf.toString(io.netty.util.CharsetUtil.UTF_8));

            buf.release();


            String res = "I am OK";

            FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1,

                    OK, Unpooled.wrappedBuffer(res.getBytes("UTF-8")));

            response.headers().set(CONTENT_TYPE, "text/plain");

            response.headers().set(CONTENT_LENGTH,

                    response.content().readableBytes());

            if (HttpHeaders.isKeepAlive(request)) {

                response.headers().set(CONNECTION, Values.KEEP_ALIVE);

            }

            ctx.write(response);

            ctx.flush();

        }

    }



    @Override

    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {

        ctx.flush();

    }



    @Override

    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {

        log.error(cause.getMessage());

        ctx.close();

    }



}

Http Client：

package com.netty.test;



import io.netty.bootstrap.Bootstrap;

import io.netty.buffer.Unpooled;

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.NioSocketChannel;

import io.netty.handler.codec.http.DefaultFullHttpRequest;

import io.netty.handler.codec.http.HttpHeaders;

import io.netty.handler.codec.http.HttpMethod;

import io.netty.handler.codec.http.HttpRequestEncoder;

import io.netty.handler.codec.http.HttpResponseDecoder;

import io.netty.handler.codec.http.HttpVersion;



import java.net.URI;



public class HttpClient {

    public void connect(String host, int port) throws Exception {

        EventLoopGroup workerGroup = new NioEventLoopGroup();



        try {

            Bootstrap b = new Bootstrap();

            b.group(workerGroup);

            b.channel(NioSocketChannel.class);

            b.option(ChannelOption.SO_KEEPALIVE, true);

            b.handler(new ChannelInitializer<SocketChannel>() {

                @Override

                public void initChannel(SocketChannel ch) throws Exception {

                    // 客户端接收到的是httpResponse响应，所以要使用HttpResponseDecoder进行解码

                    ch.pipeline().addLast(new HttpResponseDecoder());

                    // 客户端发送的是httprequest，所以要使用HttpRequestEncoder进行编码

                    ch.pipeline().addLast(new HttpRequestEncoder());

                    ch.pipeline().addLast(new HttpClientInboundHandler());

                }

            });



            // Start the client.

            ChannelFuture f = b.connect(host, port).sync();



            URI uri = new URI("http://127.0.0.1:8844");

            String msg = "Are you ok?";

            DefaultFullHttpRequest request = new DefaultFullHttpRequest(HttpVersion.HTTP_1_1, HttpMethod.GET,

                    uri.toASCIIString(), Unpooled.wrappedBuffer(msg.getBytes("UTF-8")));



            // 构建http请求

            request.headers().set(HttpHeaders.Names.HOST, host);

            request.headers().set(HttpHeaders.Names.CONNECTION, HttpHeaders.Values.KEEP_ALIVE);

            request.headers().set(HttpHeaders.Names.CONTENT_LENGTH, request.content().readableBytes());

            // 发送http请求

            f.channel().write(request);

            f.channel().flush();

            f.channel().closeFuture().sync();

        } finally {

            workerGroup.shutdownGracefully();

        }



    }



    public static void main(String[] args) throws Exception {

        HttpClient client = new HttpClient();

        client.connect("127.0.0.1", 8844);

    }

}

处理Server响应的HttpClientInboundHandler：

package com.netty.test;



import io.netty.buffer.ByteBuf;

import io.netty.channel.ChannelHandlerContext;

import io.netty.channel.ChannelInboundHandlerAdapter;

import io.netty.handler.codec.http.HttpContent;

import io.netty.handler.codec.http.HttpHeaders;

import io.netty.handler.codec.http.HttpResponse;



public class HttpClientInboundHandler extends ChannelInboundHandlerAdapter {



    @Override

    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {

        if (msg instanceof HttpResponse) 

        {

            HttpResponse response = (HttpResponse) msg;

            System.out.println("CONTENT_TYPE:" + response.headers().get(HttpHeaders.Names.CONTENT_TYPE));

        }

        if(msg instanceof HttpContent)

        {

            HttpContent content = (HttpContent)msg;

            ByteBuf buf = content.content();

            System.out.println(buf.toString(io.netty.util.CharsetUtil.UTF_8));

            buf.release();

        }

    }

}

log4j的配置：

# Root logger option
log4j.rootLogger=INFO, stdout, file

# Direct log messages to stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n

log4j.appender.file = org.apache.log4j.DailyRollingFileAppender
log4j.appender.file.File = logs/log.log
log4j.appender.file.Append = true
log4j.appender.file.Threshold = INFO
log4j.appender.file.layout = org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern = %-d{yyyy-MM-dd HH:mm:ss} %5p %c{1}:%L - %m%n