阿里雲服務器中springboot應用使用socketio和錯誤BindException：Cannot assign requested address: bind

socketio依賴：

<dependency>
    <groupId>com.corundumstudio.socketio</groupId>
    <artifactId>netty-socketio</artifactId>
    <version>1.7.17</version>
</dependency>

主程序：

@SpringBootApplication
@Configuration
public class MainApplication extends SpringBootServletInitializer {

	@Bean
	public SocketIOServer socketIOServer(){
		com.corundumstudio.socketio.Configuration config = new com.corundumstudio.socketio.Configuration();
		// 注意：如果本地測試，可以使用localhost；如果阿里雲服務器，則需指定 “內網ip”
		config.setHostname("localhost");
		config.setPort(9090);
		// 設置最大的webSocket幀內容長度限制
		config.setMaxFramePayloadLength(1024 * 1024);
		// 設置最大http內容長度限制
		config.setMaxHttpContentLength(1024 * 1024);
		return new SocketIOServer(config);
	}

	@Bean
	public SpringAnnotationScanner springAnnotationScanner(SocketIOServer socketIOServer){
		return new SpringAnnotationScanner(socketIOServer);
	}

	@Override
	protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
		return application.sources(MainApplication.class);
	}

	public static void main(String[] args) {
		SpringApplication.run(MainApplication.class, args);
	}
}

通信包裝實體：

@Data
public class SocketIoMsg {

    private String type;

    private String msg;
}

自定義socketio啓動命令，CommandLineRunner在springboot啓動時，可以預先執行一些代碼或初始化數據：

@Component
@Order(1)
public class SocketioCommandLineRunner implements CommandLineRunner {

    private Logger logger = LoggerFactory.getLogger(SocketioCommandLineRunner.class);

    private SocketIOServer socketIOServer;

    @Autowired
    public SocketioCommandLineRunner(SocketIOServer socketIOServer){
        this.socketIOServer = socketIOServer;
    }

    @Override
    public void run(String... strings) throws Exception {
        socketIOServer.start();
        logger.info("socketio server started");
    }
}

消息事件處理類：

@Component
public class SocketioMsgEventHandler {

    private Logger logger = LoggerFactory.getLogger(SocketioMsgEventHandler.class);

    public static SocketIOServer socketIOServer;

    @Autowired
    public SocketioMsgEventHandler(SocketIOServer socketIOServer){
        this.socketIOServer = socketIOServer;
    }
    @Autowired
    private PlatNoticeService platNoticeService;

    public static List<UUID> clientList = new ArrayList<>();

    @OnConnect
    @SuppressWarnings("unchecked")
    public void onConnect(SocketIOClient client){
        clientList.add(client.getSessionId());
        // 發送消息
        Response response = platNoticeService.getPlatShowList();
        if(response.getStatus().isSuccess()){
            List<PlatNoticeModel> noticeModelList = (List<PlatNoticeModel>) response.getData();
            for(PlatNoticeModel noticeModel : noticeModelList){
                client.sendEvent(PlatNoticeTypeEnum.noticeStart.toString(), noticeModel.getContent());
            }
        }
        logger.info("新的連接：" + client.getSessionId());
    }

    @OnDisconnect
    public void onDisconnect(SocketIOClient client){
        clientList.remove(client.getSessionId());
        logger.info("連接斷開：" + client.getSessionId());
    }

    @OnEvent(value = "msgEvent")
    public void msgEvent(SocketIOClient client, AckRequest ackReq, SocketIoMsg msg){
        logger.info("發來消息：" + client.getSessionId() + "，" + msg.getMsg());
        socketIOServer.getClient(client.getSessionId()).sendEvent("msgEvent", "success");
    }

    public static void sendMsg(List<UUID> msgClientList, String type, String msg){
        List<UUID> idList = new ArrayList<>();
        if(CollectionUtils.isEmpty(msgClientList)){
            idList.addAll(clientList);
        }else{
            idList.addAll(msgClientList);
        }
        for(UUID uuid : idList){
            if(uuid != null){
                SocketIOClient client = socketIOServer.getClient(uuid);
                if(client != null){
                    client.sendEvent(type, msg);
                }
            }
        }
    }
}

注意事項：

1. 如果是在本地測試，config.setHostname(“localhost”); 可以直接指定localhost
2. 但是在阿里雲服務器上，一定要指定 內網ip，然後客戶端調用時指定外網ip
3. 在阿里雲控制檯，去設置安全組，將socketio端口開放

錯誤：

java.net.BindException: Cannot assign requested address: bind
	at sun.nio.ch.Net.bind0(Native Method)
	at sun.nio.ch.Net.bind(Net.java:433)
	at sun.nio.ch.Net.bind(Net.java:425)

如果出現以上錯誤，請檢查hostname的設置，本機就是localhost，雲服務器就用服務器的ip，例如阿里雲使用內網設置