2、netty第一个例子，简单的http服务器

用netty来启动一个简单的可处理http请求的服务器。

依照前面写的使用netty的过程。贴上代码

server

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;

/**
  * @ClassName:      TestServe
  * @Description:     描述  主要作用是写一个可以支持 http 请求的伪服务器。可以看到请求的头和数据 ，也可以自己构建response
  * @CreateDate:     2019/7/3 23:08
  * @Version:        1.0
 */
public class TestServer {

    public static void main(String[] args) throws InterruptedException {
        EventLoopGroup bossGroup  = new NioEventLoopGroup();//线程，用来接收  事件循环组  死循环
        EventLoopGroup workerGroup = new NioEventLoopGroup();//线程，用来处理  事件循环组  死循环

        try{
            //启动器
            ServerBootstrap serverBootstrap = new ServerBootstrap();
            serverBootstrap.group(bossGroup, workerGroup)//添加设置两个线程组
                    .channel(NioServerSocketChannel.class)
                    .childHandler(new TestSereverInitlalizer());//这里去设置初始化类

            ChannelFuture channelFuture = serverBootstrap.bind(8899).sync();//阻塞，等待

            channelFuture.channel().closeFuture().sync();
        }finally {
            bossGroup.shutdownGracefully();//优雅关闭
            workerGroup.shutdownGracefully();
        }

    }
}

Initlalizer

import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.http.HttpServerCodec;

public class TestSereverInitlalizer extends ChannelInitializer<SocketChannel> {

    @Override
    protected void initChannel(SocketChannel ch) throws Exception {
        ChannelPipeline pipeline = ch.pipeline();

        pipeline.addLast("httpServerCodec",new HttpServerCodec());//http里用的
        pipeline.addLast("testHttpSereverHandle", new TestHttpServerHandler());//把前面设置的handler加到最后

    }
}

Handler

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.http.*;
import io.netty.util.CharsetUtil;

import java.net.URI;
import java.net.URL;

public class TestHttpServerHandler extends SimpleChannelInboundHandler<HttpObject> {

    @Override
    protected void channelRead0(ChannelHandlerContext ctx, HttpObject msg) throws Exception {

        System.out.println(msg.getClass());

        System.out.println(ctx.channel().remoteAddress());

        if(msg instanceof HttpRequest) {//如果没加这个，用curl访问时，会报错，用浏览器访问不会报错
//            System.out.println("执行了！！！！！");

            HttpRequest httpRequest = (HttpRequest) msg;

            System.out.println("请求方法名" + httpRequest.getMethod().name());

            URI uri = new URI(httpRequest.uri());
            if("/favicon.ico".equals(uri.getPath())) {
                System.out.println("请求 favicon.ico");
                return;
            }

            //向客户端返回的内容
            ByteBuf content = Unpooled.copiedBuffer("Hello world", CharsetUtil.UTF_8);
            //构建response
            FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1,HttpResponseStatus.OK,content);
            response.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/plain");
            response.headers().set(HttpHeaderNames.CONTENT_LENGTH, content.readableBytes());

            ctx.writeAndFlush(response);
            ctx.channel().close();
        }

    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        System.out.println("channel active");
        super.channelActive(ctx);
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        System.out.println("channel inactive");
        super.channelInactive(ctx);
    }

    @Override
    public void channelRegistered(ChannelHandlerContext ctx) throws Exception {
        System.out.println("channel registered");
        super.channelRegistered(ctx);
    }

    @Override
    public void channelUnregistered(ChannelHandlerContext ctx) throws Exception {
        System.out.println("channel unregistered");
        super.channelUnregistered(ctx);
    }

    @Override
    public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
        System.out.println("handler added");
        super.handlerAdded(ctx);
    }
}