BeanFactory 是 Spring IoC 容器的底层实现；

ApplicationContext 拥有 BeanFactory 的所有能力，还提供了

• Easier integration with Spring’s AOP features
• Message resource handling (for use in internationalization)
• Event publication
• Application-layer specific contexts such as the WebApplicationContext for use in web applications

摘自：https://docs.spring.io/spring-framework/docs/5.2.2.RELEASE

即更易集成 aop 特性、消息资源处理(国际化)、事件发布、应用程序层面特定的上下文如 WebApplicationContext。

除了以上，细节上还包括：

• BeanFactory 在启动的时候不会去实例化 bean，从容器中拿 bean 时才会去实例化；ApplicationContext 在启动时就把所有的 bean 全部实例化了
• BeanPostProcessor、BeanFactoryPostProcessor 接口的注册：BeanFactory 需要手动注册，ApplicationContext 则是自动

总之，ApplicationContext 是具备应用特性的 BeanFactory 超集。

代码示例：

pom

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <parent>
        <groupId>constxiong</groupId>
        <artifactId>spring-study</artifactId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
	
    <artifactId>003-spring-beanfactory-applicationcontext</artifactId>

    <properties>
        <spring-version>5.2.2.RELEASE</spring-version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring-version}</version>
        </dependency>
    </dependencies>

    <build>

    </build>
</project>

User.java

package constxiong;

public class User {
	
	private Integer id;
	
	private String name;

	public Integer getId() {
		return id;
	}

	public void setId(Integer id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	@Override
	public String toString() {
		return "User [id=" + id + ", name=" + name + "]";
	}
	
}

spring 配置文件

<?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.xsd">
	
	<bean class="constxiong.User">
		<property name="id" value="1"/>
		<property name="name" value="constxiong"/>
	</bean>

</beans>

测试代码

package constxiong;

import org.springframework.beans.factory.support.DefaultListableBeanFactory;
import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

/**
 * 测试 BeanFactory 与 ApplicationContext 的区别
 * @author ConstXiong
 */
public class Test {
	
	public static void main(String[] args) {
		String xmlPath = "META-INF/spring-beanfactory-applicationcontext.xml";
		getBeanByBeanFactory(xmlPath);
		getBeanByApplicationContext(xmlPath);
	}

	/**
	 * 通过 ClassPathXmlApplicationContext 获取 bean
	 */
	private static void getBeanByApplicationContext(String xmlPath) {
		ApplicationContext applicationContext = new ClassPathXmlApplicationContext(xmlPath);
		User user = applicationContext.getBean(User.class);
		System.out.println(user);
	}

	/**
	 *  通过 DefaultListableBeanFactory 获取 bean
	 */
	private static void getBeanByBeanFactory(String xmlPath) {
		DefaultListableBeanFactory beanFactory = new DefaultListableBeanFactory();
		XmlBeanDefinitionReader xmlReader = new XmlBeanDefinitionReader(beanFactory);
		xmlReader.loadBeanDefinitions(xmlPath);
		User user = beanFactory.getBean(User.class);
		System.out.println(user);
	}

}

说明：