WebSocket注入Bean后报null,操作不了数据库的解决方法

注入Service访问时报null，多番查询终于得以解决

我有个需求是微信小程序要通过WebSocket获取数据传到后端，进而操作数据库，给MyWebSocket处理类加了@Controller注解,通过@Resource注解注入Service,结果访问时报null，网上搜了很多，花了很长时才搞定，写此博文，即搜即用，经过整理，现附上解决方法(我用的Springboot框架)：

• 新建SpringUtil
• 修改启动类App.java
• 修改MyWebSocket处理类

---

第一步

//新建SpringUtil用来获取beanimport org.springframework.beans.BeansException;import org.springframework.context.ApplicationContext;import org.springframework.context.ApplicationContextAware;public class SpringUtil implements ApplicationContextAware{    private static ApplicationContext applicationContext = null;    @Override    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {       if(SpringUtil.applicationContext == null){           SpringUtil.applicationContext  = applicationContext;       }      System.out.println("---------------simple.plugin.spring.SpringUtil------------------------------------------------------");      System.out.println("========ApplicationContext配置成功,在普通类可以通过调用SpringUtils.getAppContext()获取applicationContext对象,applicationContext="+SpringUtil.applicationContext+"========");    }    //获取applicationContext    public static ApplicationContext getApplicationContext() {       return applicationContext;    }    //通过name获取 Bean.    public static Object getBean(String name){       return getApplicationContext().getBean(name);    }    //通过class获取Bean.    public static <T> T getBean(Class<T> clazz){       return getApplicationContext().getBean(clazz);    }    //通过name,以及Clazz返回指定的Bean    public static <T> T getBean(String name,Class<T> clazz){       return getApplicationContext().getBean(name, clazz);    }}

---

第二步

//修改启动类App.javaimport org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.boot.web.servlet.ServletComponentScan;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Import;import org.springframework.web.bind.annotation.RestController;@SpringBootApplication@ServletComponentScan@RestController@Import(value={SpringUtil.class})  //引入SpringUtilpublic class App {    /**注册Spring Util     * 这里为了和上一个冲突，所以方面名为：springUtil2     * 实际中使用springUtil     */    @Bean    public SpringUtil springUtil2(){        return new SpringUtil();        }    public static void main(String[] args) {        SpringApplication.run(App.class, args);    }}

---

第三步通过SpringUtil.getBean(BeanName)获取bean，这里的BeanName即@service（“BeanName”），注意需要强转为你的service类的类型

 //修改MyWebSocket处理类 @OnMessage    public void onMessage (String message, Session session) throws IOException {        System.out.println("来自客户端的消息:" + message);        String id = message;        //获取bean,"vodStaService"为service的Name            vodStaService service = (vodStaService) SpringUtil.getBean("vodStaService");        //更新        service.updateByVdid(id);        //查询        vodSta selectedNum = service.selectByVdid(id);        String number = selectedNum.getSelectedNum();         // 群发消息        for ( MyWebSocket item : webSocketSet ){                item.sendMessage(number);        }    }

好了，至此，这个问题完美解决，谢谢大神们的分享，有问题请留言~

这里导入bean的方法参考于大神林祥纤的博客 —— [ Spring Boot普通类调用bean ]