http://blog.csdn.net/u013252773/article/details/21254257
本文主要介绍如何通过Netty构建一个简单的http服务。
想要实现的目的是:
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。
在该实例中,会涉及到http请求的编码、解码,http响应的编码、解码,幸运的是,Netty已经为我们提供了这些工具,整个实例的逻辑图如下所示:
其中红色框中的4个类是Netty提供的,它们其实也是一种Handler,其中Encoder继承自ChannelOutboundHandler,Decoder继承自ChannelInboundHandler,它们的作用是:
1、HttpRequestEncoder:对httpRequest进行编码。
2、HttpRequestDecoder:把流数据解析为httpRequest。
3、HttpResponsetEncoder:对httpResponset进行编码。
4、HttpResponseEncoder:把流数据解析为httpResponse。
该实例涉及到的类有5个:HttpServer HttpServerInboundHandler HttpClient HttpClientInboundHandler ByteBufToBytes
1、HttpServer 启动http服务器
[java] view plaincopy
- package com.guowl.testhttpprotocol;
- 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 {
- public void start(int port) throws Exception {
- EventLoopGroup bossGroup = new NioEventLoopGroup(); // (1)
- EventLoopGroup workerGroup = new NioEventLoopGroup();
- try {
- ServerBootstrap b = new ServerBootstrap(); // (2)
- b.group(bossGroup, workerGroup).channel(NioServerSocketChannel.class) // (3)
- .childHandler(new ChannelInitializer<SocketChannel>() { // (4)
- @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) // (5)
- .childOption(ChannelOption.SO_KEEPALIVE, true); // (6)
- ChannelFuture f = b.bind(port).sync(); // (7)
- f.channel().closeFuture().sync();
- } finally {
- workerGroup.shutdownGracefully();
- bossGroup.shutdownGracefully();
- }
- }
- public static void main(String[] args) throws Exception {
- HttpServer server = new HttpServer();
- server.start(8000);
- }
- }
2、HttpServerInboundHandler 解析客户端的请求,并进行响应
[java] view plaincopy
- package com.guowl.testhttpprotocol;
- 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 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;
- import org.slf4j.Logger;
- import org.slf4j.LoggerFactory;
- import com.guowl.utils.ByteBufToBytes;
- public class HttpServerInboundHandler extends ChannelInboundHandlerAdapter {
- private static Logger logger = LoggerFactory.getLogger(HttpServerInboundHandler.class);
- private ByteBufToBytes reader;
- @Override
- public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
- if (msg instanceof HttpRequest) {
- HttpRequest request = (HttpRequest) msg;
- System.out.println("messageType:" + request.headers().get("messageType"));
- System.out.println("businessType:" + request.headers().get("businessType"));
- if (HttpHeaders.isContentLengthSet(request)) {
- reader = new ByteBufToBytes((int) HttpHeaders.getContentLength(request));
- }
- }
- if (msg instanceof HttpContent) {
- HttpContent httpContent = (HttpContent) msg;
- ByteBuf content = httpContent.content();
- reader.reading(content);
- content.release();
- if (reader.isEnd()) {
- String resultStr = new String(reader.readFull());
- System.out.println("Client said:" + resultStr);
- FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, OK, Unpooled.wrappedBuffer("I am ok"
- .getBytes()));
- response.headers().set(CONTENT_TYPE, "text/plain");
- response.headers().set(CONTENT_LENGTH, response.content().readableBytes());
- response.headers().set(CONNECTION, Values.KEEP_ALIVE);
- ctx.write(response);
- ctx.flush();
- }
- }
- }
- @Override
- public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
- logger.info("HttpServerInboundHandler.channelReadComplete");
- ctx.flush();
- }
- }
3、HttpClient 向服务器发送请求
[java] view plaincopy
- package com.guowl.testhttpprotocol;
- 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(); // (1)
- b.group(workerGroup); // (2)
- b.channel(NioSocketChannel.class); // (3)
- b.option(ChannelOption.SO_KEEPALIVE, true); // (4)
- 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(); // (5)
- URI uri = new URI("http://127.0.0.1:8000");
- String msg = "Are you ok?";
- DefaultFullHttpRequest request = new DefaultFullHttpRequest(HttpVersion.HTTP_1_1, HttpMethod.POST,
- uri.toASCIIString(), Unpooled.wrappedBuffer(msg.getBytes()));
- // 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());
- request.headers().set("messageType", "normal");
- request.headers().set("businessType", "testServerState");
- // 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", 8000);
- }
- }
4、HttpClientInboundHandler 对服务器的响应进行读取
[java] view plaincopy
- package com.guowl.testhttpprotocol;
- 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;
- import com.guowl.utils.ByteBufToBytes;
- public class HttpClientInboundHandler extends ChannelInboundHandlerAdapter {
- private ByteBufToBytes reader;
- @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 (HttpHeaders.isContentLengthSet(response)) {
- reader = new ByteBufToBytes((int) HttpHeaders.getContentLength(response));
- }
- }
- if (msg instanceof HttpContent) {
- HttpContent httpContent = (HttpContent) msg;
- ByteBuf content = httpContent.content();
- reader.reading(content);
- content.release();
- if (reader.isEnd()) {
- String resultStr = new String(reader.readFull());
- System.out.println("Server said:" + resultStr);
- ctx.close();
- }
- }
- }
- }
5、ByteBufToBytes 读取NIO的工具类,可以一次性把ByteBuf的数据读取出来,也可以把多次ByteBuf中的数据统一读取出来。
[java] view plaincopy
- package com.guowl.utils;
- import io.netty.buffer.ByteBuf;
- import io.netty.buffer.Unpooled;
- public class ByteBufToBytes {
- private ByteBuf temp;
- private boolean end = true;
- public ByteBufToBytes(int length) {
- temp = Unpooled.buffer(length);
- }
- public void reading(ByteBuf datas) {
- datas.readBytes(temp, datas.readableBytes());
- if (this.temp.writableBytes() != 0) {
- end = false;
- } else {
- end = true;
- }
- }
- public boolean isEnd() {
- return end;
- }
- public byte[] readFull() {
- if (end) {
- byte[] contentByte = new byte[this.temp.readableBytes()];
- this.temp.readBytes(contentByte);
- this.temp.release();
- return contentByte;
- } else {
- return null;
- }
- }
- public byte[] read(ByteBuf datas) {
- byte[] bytes = new byte[datas.readableBytes()];
- datas.readBytes(bytes);
- return bytes;
- }
- }
注意事项:
1、可以通过在Netty的Chanel中发送HttpRequest对象,完成发送http请求的要求,同时可以对HttpHeader进行设置。
2、可以通过HttpResponse发送http响应,同时可以对HttpHeader进行设置。
3、上面涉及到的http对象都是Netty自己封装的,不是标准的。