BeanFactory和ApplicationContext的区别

时间 2019-11-06

标签 beanfactory applicationcontext 区别繁體版

原文原文链接

Spring Bean

先从SpringBean提及，Spring Beans是被Spring容器管理的Java对象，好比：spring

public class HelloWorld { 
   private String message;  
   public void setMessage(String message){ 
      this.message  = message; 
   }  
   public void getMessage(){ 
      System.out.println("My Message : " + message); 
   } 
}

咱们通常经过Application.xml配置Spring Bean元数据。性能

<?xml version = "1.0" encoding = "UTF-8"?>
<beans xmlns = "http://www.springframework.org/schema/beans"
   xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation = "http://www.springframework.org/schema/beans
   http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
   <bean id = "helloWorld" class = "com.zoltanraffai.HelloWorld">
      <property name = "message" value = "Hello World!"/>
   </bean>
</beans>

Spring Bean被Spring容器管理以后，能够在程序中获取使用它了。this

BeanFactory

BeanFactory是Spring容器的基础接口，提供了基础的容器访问能力。code

BeanFactory提供懒加载方式，只有经过getBean方法调用获取Bean才会进行实例化。xml

经常使用的是加载XMLBeanFactory：对象

public class HelloWorldApp{ 
   public static void main(String[] args) { 
      XmlBeanFactory factory = new XmlBeanFactory (new ClassPathResource("beans.xml")); 
      HelloWorld obj = (HelloWorld) factory.getBean("helloWorld");    
      obj.getMessage();    
   }
}

ApplicationContext

ApplicationContext继承自BeanFactory接口，ApplicationContext包含了BeanFactory中全部的功能。继承

具备本身独特的特性：接口

Bean instantiation/wiriting
Bean实例化/串联
自动BeanPostProcessor注册
自动BeanFactoryPostProcessor注册
方便的MessageSource访问
ApplicationEvent发布

ApplicationContext采用的是预加载，每一个Bean都在ApplicationContext启动后实例化。get

public class HelloWorldApp{ 
   public static void main(String[] args) { 
      ApplicationContext context=new ClassPathXmlApplicationContext("beans.xml"); 
      HelloWorld obj = (HelloWorld) context.getBean("helloWorld");    
      obj.getMessage();    
   }
}

后记

ApplicationContext包含了BeanFactory全部特性，一般推荐使用前者，可是对于性能有要求的场景能够考虑使用更轻量级的BeanFactory。大多数企业应用中Application是你的首选。it