static静态类获取bean方法

工具类的某个方法想要获取bean的实例，但是工具类的方法是static的，不能使用@Autowired 注入，这个时候需要重写

SpringContextHolder；

@Slf4j
public class SpringContextHolder implements ApplicationContextAware {

    private static ApplicationContext applicationContext;

    /**
     * 获取applicationContext
     */
    public static ApplicationContext getApplicationContext() {
        checkApplicationContext();
        return applicationContext;
    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) {
        SpringContextHolder.applicationContext = applicationContext;
        log.info("get springContext is success");
    }

    /**
     * 获取spring bean
     */
    public static <T> T getBean(String beanName) {
        checkApplicationContext();
        return (T) applicationContext.getBean(beanName);
    }

    /**
     * 获取spring bean
     */
    public static <T> T getBean(String beanName, Class<T> clazz) {
        checkApplicationContext();
        return applicationContext.getBean(beanName, clazz);
    }

    /**
     * 获取spring bean
     */
    public static <T> T getBean(Class<T> clazz) {
        checkApplicationContext();
        Map<String, T> beans = applicationContext.getBeansOfType(clazz);
        if (beans.isEmpty()) {
            return null;
        }
        return beans.values().iterator().next();
    }

    private static void checkApplicationContext() {
        if (applicationContext == null) {
            throw new IllegalStateException("applicaitonContext为空，请检查配置");
        }
    }
}