java 春天全局缓存

Posted 2021-05-07

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

import java.util.Optional;

@Component
public class ApplicationContextProvider implements ApplicationContextAware {
    /**
     * 上下文对象实例
     */
    private static Optional<ApplicationContext> applicationContext = Optional.empty();

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        ApplicationContextProvider.applicationContext = Optional.ofNullable(applicationContext);
    }

    /**
     * 获取applicationContext
     *
     * @return
     */
    public static Optional<ApplicationContext> getApplicationContext() {
        return applicationContext;
    }

    /**
     * 通过name获取 Bean.
     *
     * @param name
     * @return
     */
    public static Object getBean(String name) {
        return getApplicationContext().map(a -> a.getBean(name)).orElse(null);
    }

    /**
     * 通过class获取Bean.
     *
     * @param clazz
     * @param <T>
     * @return
     */
    public static <T> T getBean(Class<T> clazz) {
        return getApplicationContext().map(a -> a.getBean(clazz)).orElse(null);
    }

    /**
     * 通过name,以及Clazz返回指定的Bean
     *
     * @param name
     * @param clazz
     * @param <T>
     * @return
     */
    public static <T> T getBean(String name, Class<T> clazz) {
        return getApplicationContext().map(a -> a.getBean(name, clazz)).orElse(null);

    }
}