NettyServer與SpringBoot集成

SpringBoot的非web工程

SpringBoot的AutoConfiguration會根據類路徑是否有servlet來判斷是不是web項目，也能夠本身強制指定。

@SpringBootApplication
public class RpcServerApplication {

    public static void main(String[] args){
        SpringApplication app = new SpringApplication(RpcServerApplication.class);
        app.setWebEnvironment(false);
        app.run(args);
    }
}

添加依賴

若是是多模塊的項目，因爲子模塊已經有parent了，因此只能把spring boot的parent放到子模塊的parent的pom文件上。

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.3.3.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
  </parent>
<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>

Spring IOC

<!-- spring ioc -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

在bean初始化以後啓動

@Component
//實現ApplicationContextAware以得到ApplicationContext中的全部bean
public class NettyServer implements ApplicationContextAware {

    private static final Logger logger = LoggerFactory.getLogger(NettyServer.class);

    private Channel channel;
    private EventLoopGroup bossGroup;
    private EventLoopGroup workerGroup;

    private Map<String, Object> exportServiceMap = new HashMap<String, Object>();

    @Value("${rpcServer.host:127.0.0.1}")
    String host;

    @Value("${rpcServer.ioThreadNum:5}")
    int ioThreadNum;
    //內核爲此套接口排隊的最大鏈接個數，對於給定的監聽套接口，內核要維護兩個隊列，未連接隊列和已鏈接隊列大小總和最大值

    @Value("${rpcServer.backlog:1024}")
    int backlog;

    @Value("${rpcServer.port:9090}")
    int port;

    /**
     * 啓動
     * @throws InterruptedException
     */
    @PostConstruct
    public void start() throws InterruptedException {
        logger.info("begin to start rpc server");
        bossGroup = new NioEventLoopGroup();
        workerGroup = new NioEventLoopGroup(ioThreadNum);

        ServerBootstrap serverBootstrap = new ServerBootstrap();
        serverBootstrap.group(bossGroup, workerGroup)
                .channel(NioServerSocketChannel.class)
                .option(ChannelOption.SO_BACKLOG, backlog)
                //注意是childOption
                .childOption(ChannelOption.SO_KEEPALIVE, true)
                .childOption(ChannelOption.TCP_NODELAY, true)
                .childHandler(new ChannelInitializer<SocketChannel>() {
                    @Override
                    protected void initChannel(SocketChannel socketChannel) throws Exception {
                        socketChannel.pipeline()
                                //真實數據最大字節數爲Integer.MAX_VALUE，解碼時自動去掉前面四個字節
                                //io.netty.handler.codec.DecoderException: java.lang.IndexOutOfBoundsException: readerIndex(900) + length(176) exceeds writerIndex(1024): UnpooledUnsafeDirectByteBuf(ridx: 900, widx: 1024, cap: 1024)
                                .addLast("decoder", new LengthFieldBasedFrameDecoder(Integer.MAX_VALUE, 0, 4, 0, 4))
                                .addLast("encoder", new LengthFieldPrepender(4, false))
                                .addLast(new RpcDecoder(RpcRequest.class))
                                .addLast(new RpcEncoder(RpcResponse.class))
                                .addLast(new ServerRpcHandler(exportServiceMap));
                    }
                });

        channel = serverBootstrap.bind(host,port).sync().channel();

        logger.info("NettyRPC server listening on port " + port + " and ready for connections...");
    }

    @PreDestroy
    public void stop() {
        logger.info("destroy server resources");
        if (null == channel) {
            logger.error("server channel is null");
        }
        bossGroup.shutdownGracefully();
        workerGroup.shutdownGracefully();
        channel.closeFuture().syncUninterruptibly();
        bossGroup = null;
        workerGroup = null;
        channel = null;
    }

    /**
     * 利用此方法獲取spring ioc接管的全部bean
     * @param ctx
     * @throws BeansException
     */
    public void setApplicationContext(ApplicationContext ctx) throws BeansException {
        Map<String, Object> serviceMap = ctx.getBeansWithAnnotation(ServiceExporter.class); // 獲取全部帶有 ServiceExporter 註解的 Spring Bean
        logger.info("獲取到全部的RPC服務:{}", serviceMap);
        if (serviceMap != null && serviceMap.size() > 0) {
            for (Object serviceBean : serviceMap.values()) {
                String interfaceName = serviceBean.getClass().getAnnotation(ServiceExporter.class)
                        .targetInterface()
                        .getName();
                logger.info("register service mapping:{}",interfaceName);
                exportServiceMap.put(interfaceName, serviceBean);
            }
        }
    }
}

工程 netty-rpc