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SpringBoot手动从BeanFactory中获取Bean

在开发中总是会遇到很多特殊情况,比如MQTT消息走到回调函数messageArrived的时候,想要将消息内容处理后存储到数据库中,但是这个时候业务的Bean还没有被注入,拿到的Bean是为NULL的,又或者解决循环依赖的问题,两个Bean之间的循环依赖可以使用@Lazy注解进行延迟加载,但是多个Bean呢?A依赖B,B依赖C,C依赖D,D又依赖A,我查到两个较好的方法,一是手动获取Bean,二是使用三级缓存,这里记录一下手动获取Bean的方法。

代码如下:

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/**
* @author zllwsy
* @Description
* @Date 2021/4/16 10:17
* @Created by zllwsy
*/
@Component
public class BeanUtil implements ApplicationContextAware {
//Spring上下文
private static ApplicationContext applicationContext;
@Override
//获取applicationContext,也就是将Spring的ApplicationContext引用赋值给自定义的ApplicationContext
public void setApplicationContext(ApplicationContext applicationContextParam) throws BeansException {
applicationContext=applicationContextParam;
}
//通过id获取Bean
public static Object getObject(String id) {
Object object = null;
object = applicationContext.getBean(id);
return object;
}

public static <T> T getObject(Class<T> tClass) {
return applicationContext.getBean(tClass);
}

public static Object getBean(String tClass) {a
return applicationContext.getBean(tClass);
}

public static <T> T getBean(Class<T> tClass) {
return applicationContext.getBean(tClass);
}
}
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@Component
public class SpringUtil implements ApplicationContextAware {
private static ApplicationContext applicationContext;

public SpringUtil() {
}

public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
if (SpringUtil.applicationContext == null) {
SpringUtil.applicationContext = applicationContext;
}

}

public static ApplicationContext getApplicationContext() {
return applicationContext;
}

public static Object getBean(String name) {
return getApplicationContext().getBean(name);
}

public static <T> T getBean(Class<T> clazz) {
return getApplicationContext().getBean(clazz);
}

public static <T> T getBean(String name, Class<T> clazz) {
return getApplicationContext().getBean(name, clazz);
}
}
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