Aware簇 - ApplicationContextAware

Spring源码走读

1. 源码

//org.springframework.context.ApplicationContextAware
public interface ApplicationContextAware extends Aware {
    void setApplicationContext(ApplicationContext var1) throws BeansException;
}

2. 作用

Spring容器在创建完成Bean之后，会调用ApplicationContextAware#setApplicationContext。实现这个接口之后，可以获取到ApplicationContext中的所有Bean。

3. 实践

1、通过ApplicationContextAware获取上下文

package win.yulongsun.demo.spring.util;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
/**
 * @author Sun.YuLong on 2018/5/8.
 */
public class SpringUtil implements ApplicationContextAware {
    protected static ApplicationContext CONTEXT;
    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        CONTEXT = applicationContext;
    }
    /**
     * 根据名称获取对象
     *
     * @param name
     * @param <T>
     * @return
     */
    public static <T> T getBean(String name) {
        return (T) CONTEXT.getBean(name);
    }
    /**
     * 根据Bean类型和名称获取对象
     *
     * @param name
     * @param requiredType
     * @param <T>
     * @return
     */
    public static <T> T getBean(String name, Class<T> requiredType) {
        return CONTEXT.getBean(name, requiredType);
    }
    /**
     * 根据Bean类型获取对象
     *
     * @param requiredType
     * @param <T>
     * @return
     */
    public static <T> T getBean(Class<T> requiredType) {
        return CONTEXT.getBean(requiredType);
    }
}