java - spring BeanFactory getbean方法是怎么搜索出对应的类的

问题描述

问 题

public interface BeanFactory {
    Object getBean(String name) throws BeansException;
    
    <T> T getBean(String name, Class<T> requiredType) throws BeansException;
    
    <T> T getBean(Class<T> requiredType) throws BeansException;
    
    ......
}

我用工具类：

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.NoSuchBeanDefinitionException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
 
public class SpringContextUtil implements ApplicationContextAware {  
   private static ApplicationContext applicationContext;     //Spring应用上下文环境  
     
   public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {  
       SpringContextUtil.applicationContext = applicationContext;  
   }  

   public static ApplicationContext getApplicationContext() {  
     return applicationContext;  
   }  
    
   public static Object getBean(String name) throws BeansException {  
     return applicationContext.getBean(name);  
   } 
   
   public static <T> T getBean(Class<T> requiredType) {
       return applicationContext.getBean(requiredType);
   }
    
public static <T> T getBean(String name, Class<T> requiredType) throws BeansException {  
     return applicationContext.getBean(name, requiredType);  
   }  
    
   public static boolean containsBean(String name) {  
     return applicationContext.containsBean(name);  
   }  
    
   public static boolean isSingleton(String name) throws NoSuchBeanDefinitionException {  
     return applicationContext.isSingleton(name);  
   }  

   @SuppressWarnings("rawtypes")
public static Class getType(String name) throws NoSuchBeanDefinitionException {  
     return applicationContext.getType(name);  
   }  
    
   public static String[] getAliases(String name) throws NoSuchBeanDefinitionException {  
     return applicationContext.getAliases(name);  
   }  
 }  

去获取spring的xml文件中的对象的时候，他们分别是怎样在xml中搜索匹配的？
getBean(Strng name) 应该是通过id或name来匹配的吧？
getBean(Class<> clzss) 呢？
另外哪里有这些用法的说明？

解决方案

这个就是装配Bean的机制。第二个getBean(Class<> clzss)明显是按照类型 获取，比方说，你要提取的Bean的类型是com.abc.def.test.service.LoginService
你只需要在这里给定参数是： getBean(com.abc.def.test.service.LoginService.class)
就可以得到一个LoginService的对象实例了

这篇关于java - spring BeanFactory getbean方法是怎么搜索出对应的类的的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！