基于Netty4的HttpServer和HttpClient的简单实现

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-numberHeader-name-1: value1Header-name-2: value2Optional request body

Http response:

HTTP/Version-number response-code response-phrase Header-name-1: value1Header-name-2: value2Optional 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。

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 optionlog4j.rootLogger=INFO, stdout, file# Direct log messages to stdoutlog4j.appender.stdout=org.apache.log4j.ConsoleAppenderlog4j.appender.stdout.Target=System.outlog4j.appender.stdout.layout=org.apache.log4j.PatternLayoutlog4j.appender.stdout.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%nlog4j.appender.file = org.apache.log4j.DailyRollingFileAppenderlog4j.appender.file.File = logs/log.loglog4j.appender.file.Append = truelog4j.appender.file.Threshold = INFOlog4j.appender.file.layout = org.apache.log4j.PatternLayoutlog4j.appender.file.layout.ConversionPattern = %-d{yyyy-MM-dd HH:mm:ss} %5p %c{1}:%L - %m%n