Spring内置功能
Spring提供了一些内置功能,也可以在Bean的生命周期阶段提供一些额外功能。内置功能主要有Aware回调接口以及InitializingBean接口。
1.BeanNameAware
实现该接口可以设置bean的名字,这是一个回调接口。
//
// Source code recreated from a .class file by IntelliJ IDEA
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//package org.springframework.beans.factory;public interface BeanNameAware extends Aware {void setBeanName(String var1);
}
2.ApplicationContextAware
实现该接口可以设置ApplicationContext容器。
//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by FernFlower decompiler)
//package org.springframework.context;import org.springframework.beans.BeansException;
import org.springframework.beans.factory.Aware;public interface ApplicationContextAware extends Aware {void setApplicationContext(ApplicationContext applicationContext) throws BeansException;
}
3.InitializingBean
实现这个这个接口在Bean的初始化前可以做一些额外处理。
//
// Source code recreated from a .class file by IntelliJ IDEA
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//package org.springframework.beans.factory;public interface InitializingBean {void afterPropertiesSet() throws Exception;
}
4.测试类
package com.example.demo2.b04;import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanNameAware;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;/*** @author zhou* @version 1.0* @description TODO* @date 2025/10/11 20:42*/
public class Mybean implements BeanNameAware, ApplicationContextAware, InitializingBean {private static final Logger log = LoggerFactory.getLogger(b04Application.class);@Overridepublic void setBeanName(String name) {log.info("当前bean "+this+"名字叫:"+name);}@Overridepublic void setApplicationContext(ApplicationContext applicationContext) throws BeansException {log.info("当前bean "+this+"容器是:"+applicationContext);}@Overridepublic void afterPropertiesSet() throws Exception {log.info("当前bean "+this+"初始化");}
}
package com.example.demo2.b04;import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.support.GenericApplicationContext;/*** @author zhou* @version 1.0* @description TODO* @date 2025/10/11 20:41*/
public class b04Application {private static final Logger log = LoggerFactory.getLogger(b04Application.class);public static void main(String[] args) {GenericApplicationContext context = new GenericApplicationContext();context.registerBean("myBean", Mybean.class);context.refresh();context.close();}
}
结果:
上面三个接口的方法都实现了,Aware接口先生效,后面才是InitializingBean接口。
5.对比@Autowired实现
@Autowired也能实现上面的Spring的内置功能,下面举一个例子。
@Autowiredpublic void test(ApplicationContext applicationContext){log.info("当前bean "+this+"容器是"+applicationContext);}
结果如下:
由于没有注册Bean的后处理器所以没生效,添加解析@Autowired的后处理器。
package com.example.demo2.b04;import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor;
import org.springframework.context.support.GenericApplicationContext;/*** @author zhou* @version 1.0* @description TODO* @date 2025/10/11 20:41*/
public class b04Application {private static final Logger log = LoggerFactory.getLogger(b04Application.class);public static void main(String[] args) {GenericApplicationContext context = new GenericApplicationContext();context.registerBean("myBean", Mybean.class);context.registerBean(AutowiredAnnotationBeanPostProcessor.class);context.refresh();context.close();}
}
相比于前面的内置功能,@Autowired的实现方式是一种拓展功能,它需要加对应的Bean后处理器才能生效,而且有时可能会失效,没有内置功能稳定。