Netty1

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：

```
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() {
@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：
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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();
}

}

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Http Client：
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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() {
@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);
}
}

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处理Server响应的HttpClientInboundHandler：
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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();
}
}
}

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参考代码：https://github.com/luxiaoxun/Code4Java

参考：

https://github.com/netty/netty