Netty EchoServer 和 EchoClient 实现

Bertha 。 2022-03-29 18:10 58阅读 0赞

### EchoServer.java ###

public class EchoServer { 
    
      private final int port;
    
      public EchoServer(int port) { 
        this.port = port;
      }
    
      public static void main(String[] args) throws Exception { 
        if (args.length != 1) { 
          System.err.println("Usage: " + EchoServer.class.getSimpleName() + " <port>");
          System.exit(1);
        }
        int port = 8080;
        try { 
          port = Integer.parseInt(args[0]);
        } catch (Exception e) { 
          System.out.println("传入端口不是数字，采用默认端口: " + port);
        }
    
        new EchoServer(port).start();
      }
    
      public void start() throws Exception { 
        final EchoServerHandler handler = new EchoServerHandler();
        EventLoopGroup group = new NioEventLoopGroup();
    
        try { 
          ServerBootstrap bootstrap = new ServerBootstrap();
          bootstrap.group(group)
            .channel(NioServerSocketChannel.class)
            .localAddress(new InetSocketAddress(port))
            .childHandler(new ChannelInitializer<SocketChannel>() { 
              protected void initChannel(SocketChannel socketChannel) throws Exception { 
                socketChannel.pipeline().addLast(handler);
              }
            });
          ChannelFuture future = bootstrap.bind().sync();
          future.channel().closeFuture().sync();
        }finally { 
          group.shutdownGracefully().sync();
        }
    
      }
    }

### EchoServerHandler.java ###

@Sharable
    public class EchoServerHandler extends ChannelInboundHandlerAdapter { 
    
      @Override
      public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception { 
        ByteBuf in = (ByteBuf) msg;
        System.out.println("Server Received: " + in.toString(CharsetUtil.UTF_8));
        ctx.write(in);
      }
    
      @Override
      public void channelReadComplete(ChannelHandlerContext ctx) throws Exception { 
        ctx.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(ChannelFutureListener.CLOSE);
      }
    
      @Override
      public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { 
        cause.printStackTrace();
        ctx.close();
      }
    }

### EchoClient.java ###

public class EchoClient { 
    
      private final String host;
      private final int port;
    
      public EchoClient(String host, int port) { 
        this.host = host;
        this.port = port;
      }
    
      public static void main(String[] args) throws Exception { 
        if (args.length != 2) { 
          System.out.println("Usage: " + EchoClient.class.getSimpleName() + " <host> <port>");
          System.exit(1);
        }
        String host = args[0];
        int port = Integer.parseInt(args[1]);
        new EchoClient(host, port).start();
      }
    
      public void start() throws Exception { 
        EventLoopGroup group = new NioEventLoopGroup();
        try { 
          Bootstrap bootstrap = new Bootstrap();
          bootstrap.group(group)
            .channel(NioSocketChannel.class)
            .remoteAddress(new InetSocketAddress(host, port))
            .handler(new ChannelInitializer<SocketChannel>() { 
              protected void initChannel(SocketChannel socketChannel) throws Exception { 
                socketChannel.pipeline().addLast(new EchoClientHandler());
              }
            });
          ChannelFuture future = bootstrap.connect().sync();
          future.channel().closeFuture().sync();
        } finally { 
          group.shutdownGracefully().sync();
        }
      }
    }

### EchoClientHandler.java ###

@Sharable
    public class EchoClientHandler extends SimpleChannelInboundHandler<ByteBuf> { 
    
      @Override
      public void channelActive(ChannelHandlerContext ctx) throws Exception { 
        ctx.writeAndFlush(Unpooled.copiedBuffer("Netty Rocks!", CharsetUtil.UTF_8));
      }
    
      protected void channelRead0(ChannelHandlerContext channelHandlerContext, ByteBuf byteBuf)
        throws Exception { 
        System.out.println("Client Received: " + byteBuf.toString(CharsetUtil.UTF_8));
      }
    
      @Override
      public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { 
        cause.printStackTrace();
        ctx.close();
      }
    
    }