定时器任务时调用Mapper运行空指针

素颜马尾好姑娘i 2024-03-23 13:50 47阅读 0赞

在进行定时任务时，类中调用Mapper总是报空指针，试了很多方法，也查了很多资料，发现是因为定时任务中无法直接调用Mapper，我是通过编写工具类获取到的bean来调用的

> 通过工具类的getBean方法获取到实例，参数为类对象，获取到bean对象就能成功调用了

import org.springframework.beans.BeansException;
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.ApplicationContextAware;
    import org.springframework.stereotype.Component;
    
    @Component
    public class SpringContextHolder implements ApplicationContextAware {
    
        private static ApplicationContext applicationContext;
    
        @Override
        public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
            SpringContextHolder.applicationContext = applicationContext;
        }
    
        public static void setContext(ApplicationContext applicationContext) {
            if (SpringContextHolder.applicationContext == null) {
                SpringContextHolder.applicationContext = applicationContext;
            }
        }
    
        public static ApplicationContext getApplicationContext() {
            assertApplicationContext();
            return applicationContext;
        }
    
        @SuppressWarnings("unchecked")
        public static <T> T getBean(String beanName) {
            assertApplicationContext();
            return (T) applicationContext.getBean(beanName);
        }
    
        public static <T> T getBean(Class<T> requiredType) {
            assertApplicationContext();
            return applicationContext.getBean(requiredType);
        }
    
        private static void assertApplicationContext() {
            if (SpringContextHolder.applicationContext == null) {
                throw new RuntimeException("applicaitonContext属性为null,请检查是否注入了SpringContextHolder!");
            }
        }
    
    }