java的netty框架什么时候调用channelInactive

在Netty框架中，当一个Channel从活跃状态变为非活跃状态时，就会调用channelInactive方法。这种情况通常发生在以下情况：

1. Channel连接意外中断，比如网络故障或者对端主动关闭连接。

2. Channel连接超时或者空闲超时，Netty会自动将其标记为非活跃状态。

3. Channel被显式地关闭。

需要注意的是，channelInactive方法并不是在所有情况下都会被调用。例如，在使用长连接时，即使某个Channel出现了网络故障或者空闲超时，也不会立即关闭它，而是等待下一次使用时再进行重连。在这种情况下，channelInactive方法就不会被调用。

相关问题

netty框架怎么调用webSocket服务方法

使用Netty框架调用WebSocket服务方法的步骤如下：

1. 导入相关依赖
在Maven的pom.xml文件中加入以下依赖：

<dependency>
    <groupId>io.netty</groupId>
    <artifactId>netty-all</artifactId>
    <version>4.1.42.Final</version>
</dependency>
<dependency>
    <groupId>io.netty</groupId>
    <artifactId>netty-transport-native-epoll</artifactId>
    <version>4.1.42.Final</version>
    <classifier>linux-x86_64</classifier>
</dependency>
<dependency>
    <groupId>io.netty</groupId>
    <artifactId>netty-transport-native-kqueue</artifactId>
    <version>4.1.42.Final</version>
    <classifier>osx-x86_64</classifier>
</dependency>

2. 编写WebSocket服务类
创建一个类来实现WebSocket服务，使用Netty的WebSocketServerHandler类来处理WebSocket消息。在这个类中，我们需要实现以下方法：

public class WebSocketServer extends SimpleChannelInboundHandler<WebSocketFrame> {
    // 连接建立时触发
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        // TODO
    }

    // 连接关闭时触发
    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        // TODO
    }

    // 处理WebSocket帧消息
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, WebSocketFrame msg) throws Exception {
        // TODO
    }

    // 异常处理
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        // TODO
    }
}

3. 启动WebSocket服务
在main方法中启动WebSocket服务：

public static void main(String[] args) throws Exception {
    EventLoopGroup bossGroup = new NioEventLoopGroup();
    EventLoopGroup workerGroup = new NioEventLoopGroup();
    try {
        ServerBootstrap bootstrap = new ServerBootstrap();
        bootstrap.group(bossGroup, workerGroup)
                 .channel(NioServerSocketChannel.class)
                 .childHandler(new ChannelInitializer<SocketChannel>() {
                     @Override
                     public void initChannel(SocketChannel ch) throws Exception {
                         ChannelPipeline pipeline = ch.pipeline();
                         pipeline.addLast(new HttpServerCodec());
                         pipeline.addLast(new ChunkedWriteHandler());
                         pipeline.addLast(new HttpObjectAggregator(65536));
                         pipeline.addLast(new WebSocketServerProtocolHandler("/websocket"));
                         pipeline.addLast(new WebSocketServer());
                     }
                 });

        ChannelFuture f = bootstrap.bind(8080).sync();
        f.channel().closeFuture().sync();
    } finally {
        bossGroup.shutdownGracefully();
        workerGroup.shutdownGracefully();
    }
}

4. 调用WebSocket服务方法
使用WebSocket客户端来调用WebSocket服务方法：

WebSocketClient client = new WebSocketClient();
client.connect(new URI("ws://localhost:8080/websocket"), new WebSocketHandler() {
    @Override
    public void onOpen(ServerHandshake handshake) {
        // 连接建立时触发
    }

    @Override
    public void onMessage(String message) {
        // 收到消息时触发
    }

    @Override
    public void onClose(int code, String reason, boolean remote) {
        // 连接关闭时触发
    }

    @Override
    public void onError(Exception ex) {
        // 异常处理
    }
});

client.send("hello world"); // 调用WebSocket服务方法

java rpc netty框架代码

以下是一个简单的 Java RPC Netty 框架代码实现：

// 定义 RPC 请求实体类
public class RpcRequest implements Serializable {
    private String className;
    private String methodName;
    private Object[] parameters;

    // 省略 getter 和 setter 方法
}

// 定义 RPC 响应实体类
public class RpcResponse implements Serializable {
    private Object result;
    private String error;

    // 省略 getter 和 setter 方法
}

// 定义 RPC 服务接口
public interface RpcService {
    // 定义服务方法
    public int add(int a, int b);
}

// 实现 RPC 服务接口
public class RpcServiceImpl implements RpcService {
    @Override
    public int add(int a, int b) {
        return a + b;
    }
}

// 定义 RPC 服务器端
public class RpcServer {
    private static final Logger LOGGER = LoggerFactory.getLogger(RpcServer.class);

    private String host;
    private int port;

    public RpcServer(String host, int port) {
        this.host = host;
        this.port = port;
    }

    public void start() throws InterruptedException {
        // 创建线程池
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
            // 配置服务器启动类
            ServerBootstrap b = new ServerBootstrap();
            b.group(bossGroup, workerGroup)
                .channel(NioServerSocketChannel.class)
                .childHandler(new ChannelInitializer<SocketChannel>() {
                    @Override
                    public void initChannel(SocketChannel ch) throws Exception {
                        // 添加解码器和编码器
                        ch.pipeline().addLast(new ObjectDecoder(ClassResolvers.cacheDisabled(null)));
                        ch.pipeline().addLast(new ObjectEncoder());
                        // 添加业务处理类
                        ch.pipeline().addLast(new RpcServerHandler());
                    }
                })
                .option(ChannelOption.SO_BACKLOG, 128)
                .childOption(ChannelOption.SO_KEEPALIVE, true);

            // 启动服务器
            ChannelFuture f = b.bind(host, port).sync();

            LOGGER.info("Server started on {}:{}", host, port);

            // 等待直到服务器 socket 关闭
            f.channel().closeFuture().sync();
        } finally {
            workerGroup.shutdownGracefully();
            bossGroup.shutdownGracefully();
        }
    }

    // 定义业务处理类
    private class RpcServerHandler extends ChannelInboundHandlerAdapter {
        @Override
        public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
            RpcRequest request = (RpcRequest) msg;
            LOGGER.info("Received request: {}", request);

            // 调用服务
            RpcResponse response = new RpcResponse();
            try {
                Class<?> clazz = Class.forName(request.getClassName());
                Method method = clazz.getMethod(request.getMethodName(), request.getParameters().getClass());
                Object result = method.invoke(clazz.newInstance(), request.getParameters());
                LOGGER.info("Result: {}", result);
                response.setResult(result);
            } catch (Exception e) {
                LOGGER.error("Error occurred while invoking service: {}", e.getMessage());
                response.setError(e.getMessage());
            }

            // 返回响应
            ctx.writeAndFlush(response);
        }

        @Override
        public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
            LOGGER.error("Error occurred in server: {}", cause.getMessage());
            ctx.close();
        }
    }
}

// 定义 RPC 客户端
public class RpcClient {
    private static final Logger LOGGER = LoggerFactory.getLogger(RpcClient.class);

    private String host;
    private int port;

    public RpcClient(String host, int port) {
        this.host = host;
        this.port = port;
    }

    public Object invoke(String className, String methodName, Object... parameters) {
        // 创建连接
        EventLoopGroup group = new NioEventLoopGroup();
        try {
            Bootstrap b = new Bootstrap();
            b.group(group)
                .channel(NioSocketChannel.class)
                .handler(new ChannelInitializer<SocketChannel>() {
                    @Override
                    public void initChannel(SocketChannel ch) throws Exception {
                        // 添加解码器和编码器
                        ch.pipeline().addLast(new ObjectDecoder(ClassResolvers.cacheDisabled(null)));
                        ch.pipeline().addLast(new ObjectEncoder());
                        // 添加业务处理类
                        ch.pipeline().addLast(new RpcClientHandler());
                    }
                })
                .option(ChannelOption.SO_KEEPALIVE, true);

            // 连接服务器
            ChannelFuture f = b.connect(host, port).sync();

            LOGGER.info("Connected to server {}:{}", host, port);

            // 发送请求
            RpcRequest request = new RpcRequest();
            request.setClassName(className);
            request.setMethodName(methodName);
            request.setParameters(parameters);
            f.channel().writeAndFlush(request);

            // 等待服务器响应
            RpcResponse response = RpcClientHandler.getResponse();
            if (response.getError() != null) {
                LOGGER.error("Error occurred while invoking service: {}", response.getError());
            } else {
                LOGGER.info("Result: {}", response.getResult());
                return response.getResult();
            }

            // 关闭连接
            f.channel().closeFuture().sync();
        } catch (Exception e) {
            LOGGER.error("Error occurred in client: {}", e.getMessage());
        } finally {
            group.shutdownGracefully();
        }

        return null;
    }

    // 定义业务处理类
    private static class RpcClientHandler extends ChannelInboundHandlerAdapter {
        private static RpcResponse response;

        public static RpcResponse getResponse() {
            return response;
        }

        @Override
        public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
            response = (RpcResponse) msg;
            LOGGER.info("Received response: {}", response);
        }

        @Override
        public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
            LOGGER.error("Error occurred in client: {}", cause.getMessage());
            ctx.close();
        }
    }
}

// 测试代码
public class RpcTest {
    public static void main(String[] args) throws InterruptedException {
        // 启动服务器
        RpcServer server = new RpcServer("localhost", 8080);
        server.start();

        // 等待服务器启动
        Thread.sleep(1000);

        // 创建客户端并调用服务
        RpcClient client = new RpcClient("localhost", 8080);
        RpcService service = (RpcService) client.invoke("RpcServiceImpl", "add", 1, 2);
        System.out.println(service.add(1, 2));
    }
}

以上代码实现了一个简单的 Java RPC Netty 框架，包括 RPC 请求和响应实体类、RPC 服务接口和实现类、RPC 服务器端和客户端。其中，RPC 服务器端和客户端都使用了 Netty 框架，通过序列化和反序列化实现了数据的传输和处理。在测试代码中，我们启动了一个 RPC 服务器，并通过客户端调用了 RPC 服务。