spring---ApplicationContextAware接口--获取ApplicationContext

类实现ApplicationContextAware接口的setApplicationContext方法 spring启动时会把ApplicationContext通过setApplicationContext方法给你，以后就能根据需要getBean

SpringUtil.java

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.annotation.BeanFactoryAnnotationUtils;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;

/**
 * spring工具类，静态工具方法获取bean
 *
 * @author zhanghui
 * @date 2019/5/29
 */
@Component
public class SpringUtil implements ApplicationContextAware {

    private static ApplicationContext 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);
    }

    // 通过class，Qulifier值取同类型的某个bean
    public static <T> T getBean(Class<T> clazz, String qualifier) {
        return BeanFactoryAnnotationUtils.qualifiedBeanOfType(
                SpringUtil.getApplicationContext().getAutowireCapableBeanFactory(),
                clazz,
                qualifier);
    }

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