spring-core-3-28 | 使用Spring IoC容器：选BeanFactory还是ApplicationContext？

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使用Spring IoC 容器

BeanFactory 是Spring 底层IoC 容器

ApplicationContext 是具备应用特性的BeanFactory 超集

以前有种结论：BeanFactory 是 Spring 框架自己用的，ApplicationContext 是给开发者用的。

代码示例

/** Licensed to the Apache Software Foundation (ASF) under one or more* contributor license agreements.  See the NOTICE file distributed with* this work for additional information regarding copyright ownership.* The ASF licenses this file to You under the Apache License, Version 2.0* (the "License"); you may not use this file except in compliance with* the License.  You may obtain a copy of the License at**     http://www.apache.org/licenses/LICENSE-2.0** Unless required by applicable law or agreed to in writing, software* distributed under the License is distributed on an "AS IS" BASIS,* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.* See the License for the specific language governing permissions and* limitations under the License.*/
package org.geekbang.thinking.in.spring.ioc.overview.container;import org.geekbang.thinking.in.spring.ioc.overview.domain.User;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.ListableBeanFactory;
import org.springframework.beans.factory.support.DefaultListableBeanFactory;
import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;import java.util.Map;/*** 28 | 使用Spring IoC容器：选BeanFactory还是ApplicationContext?** {@link BeanFactory} 作为 IoC 容器示例* BeanFactory 是Spring 底层IoC 容器, 从下面的例子可以看出, 如果你没有什么复杂的路径之类, BeanFactory 完全可以胜任你的工作** @author <a href="mailto:mercyblitz@gmail.com">Mercy</a>* @since*/
public class BeanFactoryAsIoCContainerDemo {public static void main(String[] args) {// 创建 BeanFactory 容器DefaultListableBeanFactory beanFactory = new DefaultListableBeanFactory();// 创建 XmlBeanDefinitionReader 用来读取配置, 这个类是一个底层的APIXmlBeanDefinitionReader reader = new XmlBeanDefinitionReader(beanFactory);// XML 配置文件 ClassPath 路径String location = "classpath:/META-INF/dependency-lookup-context.xml";// 加载配置int beanDefinitionsCount = reader.loadBeanDefinitions(location);System.out.println("Bean 定义加载的数量：" + beanDefinitionsCount);// 依赖查找集合对象lookupCollectionByType(beanFactory);}private static void lookupCollectionByType(BeanFactory beanFactory) {if (beanFactory instanceof ListableBeanFactory) {ListableBeanFactory listableBeanFactory = (ListableBeanFactory) beanFactory;Map<String, User> users = listableBeanFactory.getBeansOfType(User.class);System.out.println("查找到的所有的 User 集合对象：" + users);}}}

/** Licensed to the Apache Software Foundation (ASF) under one or more* contributor license agreements.  See the NOTICE file distributed with* this work for additional information regarding copyright ownership.* The ASF licenses this file to You under the Apache License, Version 2.0* (the "License"); you may not use this file except in compliance with* the License.  You may obtain a copy of the License at**     http://www.apache.org/licenses/LICENSE-2.0** Unless required by applicable law or agreed to in writing, software* distributed under the License is distributed on an "AS IS" BASIS,* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.* See the License for the specific language governing permissions and* limitations under the License.*/
package org.geekbang.thinking.in.spring.ioc.overview.container;import org.geekbang.thinking.in.spring.ioc.overview.domain.User;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.ListableBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;import java.util.Map;/*** 注解能力 {@link ApplicationContext} 作为 IoC 容器示例* ApplicationContext 是具备应用特性的BeanFactory 超集** @Configuration 注册并不是必须的，不过标注它之后 Bean 的类被 CGLib 提升。* @author <a href="mailto:mercyblitz@gmail.com">Mercy</a>* @since*/
@Configuration
public class AnnotationApplicationContextAsIoCContainerDemo {public static void main(String[] args) {// 创建 BeanFactory 容器AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext();// 将当前类 AnnotationApplicationContextAsIoCContainerDemo 作为配置类（Configuration Class）applicationContext.register(AnnotationApplicationContextAsIoCContainerDemo.class);// 启动应用上下文applicationContext.refresh();// 依赖查找集合对象lookupCollectionByType(applicationContext);applicationContext.close();}/*** 通过 Java 注解的方式，定义了一个 Bean* 相当于用 Java 代码 进行配置*/@Beanpublic User user() {User user = new User();user.setId(1L);user.setName("小马哥");return user;}private static void lookupCollectionByType(BeanFactory beanFactory) {if (beanFactory instanceof ListableBeanFactory) {ListableBeanFactory listableBeanFactory = (ListableBeanFactory) beanFactory;Map<String, User> users = listableBeanFactory.getBeansOfType(User.class);System.out.println("查找到的所有的 User 集合对象：" + users);}}}