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springboot获取getBean方法以及Applicati

springboot获取getBean方法以及Applicati

作者: 志华2020 | 来源:发表于2020-10-22 10:46 被阅读0次

    场景:在springboot多模块中使用getBean获取bean导致空指针异常。

     @Test
      public void test1(){
          IUserService userService = SpringContextHolder.getBean(UserServiceImpl.class);
          User user = userService.getUserByMobile("18782080356");
          System.out.println(user);
      }
    
    

    假如有个工程有common模块admin(启动类模块)模块,获取getBean的类在admin中,则不会报空指针,如果在common模块中,在admin模块中调用,则会报空指针异常,解决方法,使用@Import导入getBean方法所在的类

    @SpringBootApplication
    @Import(SpringContextHolder.class)
    public class AdminApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(OathServiceApplication.class, args);
        }
    
    }
    
    
    import org.springframework.aop.framework.AopContext;
    import org.springframework.beans.BeansException;
    import org.springframework.beans.factory.NoSuchBeanDefinitionException;
    import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
    import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
    import org.springframework.stereotype.Component;
    
    import java.lang.annotation.Annotation;
    import java.util.Map;
    
    /**
     * spring工具类 方便在非spring管理环境中获取bean
     *
     * @author ruoyi
     */
    @Component
    public final class SpringContextHolder implements BeanFactoryPostProcessor
    {
        /** Spring应用上下文环境 */
        private static ConfigurableListableBeanFactory beanFactory;
    
        @Override
        public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException
        {
            SpringContextHolder.beanFactory = beanFactory;
        }
    
        /**
         * 获取对象
         *
         * @param name
         * @return Object 一个以所给名字注册的bean的实例
         * @throws org.springframework.beans.BeansException
         *
         */
        @SuppressWarnings("unchecked")
        public static <T> T getBean(String name) throws BeansException
        {
            return (T) beanFactory.getBean(name);
        }
    
        /**
         * 获取类型为requiredType的对象
         *
         * @param clz
         * @return
         * @throws org.springframework.beans.BeansException
         *
         */
        public static <T> T getBean(Class<T> clz) throws BeansException
        {
            T result = (T) beanFactory.getBean(clz);
            return result;
        }
    
        /**
         * 如果BeanFactory包含一个与所给名称匹配的bean定义,则返回true
         *
         * @param name
         * @return boolean
         */
        public static boolean containsBean(String name)
        {
            return beanFactory.containsBean(name);
        }
    
        /**
         * 判断以给定名字注册的bean定义是一个singleton还是一个prototype。 如果与给定名字相应的bean定义没有被找到,将会抛出一个异常(NoSuchBeanDefinitionException)
         *
         * @param name
         * @return boolean
         * @throws org.springframework.beans.factory.NoSuchBeanDefinitionException
         *
         */
        public static boolean isSingleton(String name) throws NoSuchBeanDefinitionException
        {
            return beanFactory.isSingleton(name);
        }
    
        /**
         * @param name
         * @return Class 注册对象的类型
         * @throws org.springframework.beans.factory.NoSuchBeanDefinitionException
         *
         */
        public static Class<?> getType(String name) throws NoSuchBeanDefinitionException
        {
            return beanFactory.getType(name);
        }
    
        /**
         * 如果给定的bean名字在bean定义中有别名,则返回这些别名
         *
         * @param name
         * @return
         * @throws org.springframework.beans.factory.NoSuchBeanDefinitionException
         *
         */
        public static String[] getAliases(String name) throws NoSuchBeanDefinitionException
        {
            return beanFactory.getAliases(name);
        }
    
    
        public static Map<String, Object> getBeansWithAnnotation(Class<? extends Annotation> annotationType){
            return beanFactory.getBeansWithAnnotation(annotationType);
        }
    
        /**
         * 获取aop代理对象
         *
         * @param invoker
         * @return
         */
        @SuppressWarnings("unchecked")
        public static <T> T getAopProxy(T invoker)
        {
            return (T) AopContext.currentProxy();
        }
    }
    
    ``

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