mynotes/spring/Spring默认BeanName.md

先说结论： 1、XML配置和注解生成默认BeanName的机制是不同的 2、XML配置默认BeanName = 全类名 + # + 数字，如 com.anyway.p2024.service.impl.BigHouseServiceImpl#0 3、注解默认BeanName = 短类名首字母变成小写，如 bigHouseServiceImpl

**注意：如果短类名前2个字母都是大写，则保持短类名不变，比如 ALibaba**

示例

com.anyway.p2024.service.BigHouseService

public interface BigHouseService {  
}

com.anyway.p2024.service.impl.BigHouseServiceImpl

@Service  
public class BigHouseServiceImpl implements BigHouseService {  
}

com.anyway.p2024.service.impl.BigHouseServiceImpl2

@Service  
public class BigHouseServiceImpl2 implements BigHouseService {  
}

com.anyway.p2024.domain.ALibaba

@Component  
public class ALibaba {  
}

applicationContext.xml

<context:annotation-config />  
<context:component-scan base-package="com.anyway" />  
  
<bean class="com.anyway.p2024.service.impl.BigHouseServiceImpl" />  
<bean class="com.anyway.p2024.domain.ALibaba" />  
<bean class="com.anyway.p2024.domain.ALibaba" />

Demo04.java

ApplicationContext ac = new ClassPathXmlApplicationContext("classpath:applicationContext.xml");  
System.out.println(JSON.toJSON(BeanFactoryUtils.beanNamesForTypeIncludingAncestors(ac, BigHouseService.class)));  
System.out.println(JSON.toJSON(BeanFactoryUtils.beanNamesForTypeIncludingAncestors(ac, ALibaba.class)));

输出如下：

["bigHouseServiceImpl","bigHouseServiceImpl2","com.anyway.p2024.service.impl.BigHouseServiceImpl#0"]
["ALibaba","com.anyway.p2024.domain.ALibaba#0","com.anyway.p2024.domain.ALibaba#1"]

思考题： 如果将 com.anyway.p2024.domain.ALibaba 复制到 com.anyway.p2024.service.ALibaba ，执行 Demo04.java 会输出什么？