SpringBoot项目整合Netty启动失败的常见错误总结

Caused by: java.net.BindException: Address already in use: bind

@Value("${netty.port:8081}")
private Integer nettyPort;

spring:
  main:
    web-application-type: none

@Component
@Order(value = 1)
public class NettyServer implements ApplicationRunner {
    
    @Override
    @Async // 添加异步注解
    public void run(ApplicationArguments args) throws Exception {
        startNetty();
    }
    
    private void startNetty() {
        // Netty启动代码
    }
}

@SpringBootApplication
@EnableAsync
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

Field redisUtils in NettyServerHandler required a bean of type 'RedisUtils' that could not be found.

@Component
public class NettyServerHandler extends ChannelInboundHandlerAdapter {
    private static Log log = LogFactory.getLog(NettyServerHandler.class);
    @Autowired
    private RedisUtils redisUtils;
    
    private static NettyServerHandler instance;
    
    @PostConstruct
    public void init() {
        instance = this;
    }
    
    public static NettyServerHandler getInstance() {
        return instance;
    }
}

java.lang.NoSuchMethodError: io.netty.util.internal.AppendableCharSequence.setLength(I)V

<dependency>
    <groupId>io.netty</groupId>
    <artifactId>netty-all</artifactId>
    <version>4.1.85.Final</version> <!-- 与Spring Boot版本匹配 -->
</dependency>

java.lang.IllegalArgumentException: Channel type not supported: class io.netty.channel.socket.nio.NioServerSocketChannel

ServerBootstrap bootstrap = new ServerBootstrap();
bootstrap.group(bossGroup, workerGroup)
         .channel(NioServerSocketChannel.class) // 确保使用正确的Channel类型
         .childHandler(new ChannelInitializer<SocketChannel>() {
             @Override
             protected void initChannel(SocketChannel ch) throws Exception {
                 ch.pipeline().addLast(new MyHandler());
             }
         });

java.lang.IllegalStateException: Unable to start the netty server

EventLoopGroup bossGroup = new NioEventLoopGroup(1); // 通常1个线程足够
EventLoopGroup workerGroup = new NioEventLoopGroup(4); // 4个线程，根据需求调整

@Component
@Order(value = 1) // 优先于其他组件启动
public class NettyServer implements ApplicationRunner {
    // ...
}

Exception in thread "main" java.lang.IllegalStateException: Failed to execute ApplicationRunner

@Override
public void run(ApplicationArguments args) throws Exception {
    try {
        startNetty();
    } catch (Exception e) {
        log.error("Netty server start failed", e);
        // 处理异常，避免应用完全崩溃
    }
}