SpringBoot集成Netty，Handler中@Autowired注解为空

转载自：https://blog.csdn.net/u012138272/article/details/80502684

 

最近建了个技术交流群，然后好多小伙伴都问关于Netty的问题，尤其今天的问题最特殊，功能大概是要在Netty接收消息时把数据写入数据库，那个小伙伴用的是 Spring Boot + MyBatis + Netty，所以就碰到了Handler中@Autowired注解为空的问题

参考了一些大神的博文，Spring Boot非controller使用@Autowired注解注入为null的问题，得到结论:

首先改造一下Application，实现ApplicationContextAware接口，这里这样写是考虑到使用完还要释放，所以写的比较复杂

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.support.DefaultListableBeanFactory;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;

@SpringBootApplication
public class SpbNettyApplication implements ApplicationContextAware {

    private static ApplicationContext applicationContext;
    private static DefaultListableBeanFactory defaultListableBeanFactory;

    public static void main(String[] args) {
        SpringApplication.run(SpbNettyApplication.class, args);
        new EchoServer().start(1234);
    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.applicationContext = applicationContext;
        defaultListableBeanFactory = (DefaultListableBeanFactory)applicationContext.getAutowireCapableBeanFactory();
    }

    public static T getBean(Class clazz) {
        BeanDefinitionBuilder beanDefinitionBuilder = BeanDefinitionBuilder.genericBeanDefinition(clazz);
        String className = clazz.getName();
        defaultListableBeanFactory.registerBeanDefinition(className, beanDefinitionBuilder.getBeanDefinition());
        return (T) applicationContext.getBean(className);
    }

    public static void destroy(String className){
        defaultListableBeanFactory.removeBeanDefinition(className);
        System.out.println("destroy " + className);
    }

}

这时候就可以在Netty的Handler中为所欲为啦！

import com.avanty.spbnetty.pojo.Car;
import com.avanty.spbnetty.service.CarServiceImpl;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;

public class EchoHandler extends ChannelInboundHandlerAdapter {

    @Override
    public void channelActive(ChannelHandlerContext ctx) {

    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg){
        System.out.println(ctx.channel().remoteAddress() + "  " + msg.toString());
        ctx.channel().write("recv : " + msg.toString());
        ctx.channel().flush();

        Car car = new Car();
        car.setCarBrand("Mustang");
        car.setCarNum("789632");

        CarServiceImpl carServiceImpl = SpbNettyApplication.getBean(CarServiceImpl.class);
        carServiceImpl.addCar(car);
        SpbNettyApplication.destroy(CarServiceImpl.class.getName());

    }

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) {

    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {

    }

    @Override
    public void handlerRemoved(ChannelHandlerContext ctx) {
        System.out.println("offline " + ctx.channel().remoteAddress());
    }

}