Springboot使用Websocket的时候调取IOC管理的Bean报空指针异常问题

import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.config.annotation.EnableWebSocket;
import org.springframework.web.socket.config.annotation.WebSocketConfigurer;
import org.springframework.web.socket.config.annotation.WebSocketHandlerRegistry;

@Configuration
@EnableWebSocket
public class WebSocketConfig implements WebSocketConfigurer {

    private final MyWebSocketHandler myWebSocketHandler;

    public WebSocketConfig(MyWebSocketHandler myWebSocketHandler) {
        this.myWebSocketHandler = myWebSocketHandler;
    }

    @Override
    public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
        registry.addHandler(myWebSocketHandler, "/websocket").setAllowedOrigins("*");
    }
}

import org.springframework.web.socket.TextMessage;
import org.springframework.web.socket.WebSocketSession;
import org.springframework.web.socket.handler.TextWebSocketHandler;
import org.springframework.stereotype.Component;

@Component
public class MyWebSocketHandler extends TextWebSocketHandler {

    private final SomeService someService;

    public MyWebSocketHandler(SomeService someService) {
        this.someService = someService;
    }

    @Override
    public void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception {
        String payload = message.getPayload();
        System.out.println("消息为：" + payload);
        someService.doSomething();  // 使用 Spring Bean
        session.sendMessage(new TextMessage("servet 发送：" + payload));
    }
}

import javax.websocket.server.ServerEndpointConfig;
import org.springframework.web.context.ContextLoader;
import org.springframework.web.context.WebApplicationContext;

public class SpringConfigurator extends ServerEndpointConfig.Configurator {

    @Override
    public <T> T getEndpointInstance(Class<T> clazz) throws InstantiationException {
        WebApplicationContext context = ContextLoader.getCurrentWebApplicationContext();
        if (context == null) {
            throw new InstantiationException("Unable to get Spring context.");
        }
        return context.getAutowireCapableBeanFactory().createBean(clazz);
    }
}

import javax.websocket.OnMessage;
import javax.websocket.server.ServerEndpoint;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

@ServerEndpoint(value = "/websocket", configurator = SpringConfigurator.class)
@Component
public class MyWebSocket {

    @Autowired
    private SomeService someService;  // 由 Spring 管理的 Bean

    @OnMessage
    public String onMsg(String text) throws IOException {
        System.out.println("消息为：" + text);
        someService.doSomething();  // 使用 Spring Bean
        return "servet 发送：" + text;
    }
}

import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;

@Component
public class ApplicationContextProvider implements ApplicationContextAware {

    private static ApplicationContext context;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) {
        context = applicationContext;
    }

    public static ApplicationContext getApplicationContext() {
        return context;
    }
}

import javax.websocket.OnMessage;
import javax.websocket.server.ServerEndpoint;
import org.springframework.stereotype.Component;

@ServerEndpoint(value = "/websocket")
@Component
public class MyWebSocket {

    private SomeService someService;

    public MyWebSocket() {
        this.someService = ApplicationContextProvider.getApplicationContext().getBean(SomeService.class);
    }

    @OnMessage
    public String onMsg(String text) throws IOException {
        System.out.println("消息为：" + text);
        someService.doSomething();  // 使用 Spring Bean
        return "servet 发送：" + text;
    }
}