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);
     }
 }