Spring中BeanFactory和ApplicationContext的区别

Posted 2020-09-06 大头杀马特

我用一个例子去测试BeanFactory和ApplicationContext的区别

首先建立一个bean

public class User {
//声明无参构造，打印一句话，监测对象创建时机
    public User(){
        System.out.println("User对象初始化");
    }
}

然后再建立测试类

public class UserTest {
    @Test
    public void ApplicationContexttest(){
        ApplicationContext context=new ClassPathXmlApplicationContext("applicationContext.xml");

    }
    @Test
    public void BeanFactorytest(){
        Resource resource=new PathResource("applicationContext.xml");
        BeanFactory beanFactory=new XmlBeanFactory(resource);
    }
}

配置xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd ">


    <bean name="user" class="bean.entity.User"></bean>


</beans>

 

执行 ApplicationContexttest()方法

结果：

说明user对象在ApplicationContext对象创建时user对象就已经初始化

执行BeanFactorytest()方法 

结果：

BeanFactory对象初始化时并没有初始化user对象

然后向两个方法添加获取对象的代码

public class UserTest {
    @Test
    public void ApplicationContexttest(){
        ApplicationContext context=new ClassPathXmlApplicationContext("applicationContext.xml");
        System.out.println(context.getBean("user"));
        System.out.println(context.getBean("user"));

    }
    @Test
    public void BeanFactorytest(){
        Resource resource=new ClassPathResource("applicationContext.xml");
        BeanFactory beanFactory=new XmlBeanFactory(resource);
        System.out.println(beanFactory.getBean("user"));
        System.out.println(beanFactory.getBean("user"));
    }
}

执行 ApplicationContexttest()方法

结果：

两次对象内存地址一致

执行BeanFactorytest()方法 

结果：

在执行getBean（）方法时才创建user对象