使用 Spring IoC 容器-12

使用 Spring IoC 容器

• BeanFactory 是 Spring 底层 IoC 容器

  package org.xiaoge.thinking.in.spring.ioc.overview.dependency.container;
  
  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 org.xiaoge.thinking.in.spring.ioc.overview.domain.User;
  
  import java.util.Map;
  
  /**
   * {@like BeanFactory} 作为 Ioc 容器示例
   * @Classname IoCContainer
   * @Date 2022/11/2 13:29
   * @Created by ZhangXiao
   * @Description TODO
   *
   * 1. BeanFactory容器 就 没有ApplicationContext提供的那些特性了
   * 2. 这是一个典型的IoC底层容器
   * 3. 如果你是xml场景的时候, 并且并且不需要那么多复杂路径的时候, 你用这个东西完全足以胜任你的工作
   *
   */
  public class BeanFactoryAsIoCContainerDemo {
        
        
  
      public static void main(String[] args) {
        
        
  
          // 创建BeanFactory容器
          DefaultListableBeanFactory beanFactory = new DefaultListableBeanFactory();
          XmlBeanDefinitionReader 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);
  
          // 依赖查找集合对对象
          lookupCollectionByType(beanFactory);
      }
  
      /**
       * 根据类型查找集合对象
       * @param beanFactory
       */
      private static void lookupCollectionByType(BeanFactory beanFactory) {
        
        
          if (beanFactory instanceof ListableBeanFactory) {
        
        
              ListableBeanFactory listableBeanFactory = (ListableBeanFactory) beanFactory;
              Map<String, User> map = listableBeanFactory.getBeansOfType(User.class);
              System.out.println("查找到所有的 user 集合对象: " + map);
          }
      }
  }
  
  
  /*
  	运行结果
  		Bean 定义加载的数量: 3
  		查找到所有的 user 集合对象: {user=User{id=1, name='xiaoge'}, superUser=SuperUser{address='武汉'} User{id=1, name='xiaoge'}}
  
  */
  

• ApplicationContext 是具备应用特性的 BeanFactory 超集

  package org.xiaoge.thinking.in.spring.ioc.overview.dependency.container;
  
  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 org.springframework.context.annotation.AnnotationConfigApplicationContext;
  import org.springframework.context.annotation.Bean;
  import org.springframework.context.annotation.Configuration;
  import org.springframework.context.annotation.EnableMBeanExport;
  import org.xiaoge.thinking.in.spring.ioc.overview.domain.User;
  
  import javax.jws.soap.SOAPBinding;
  import java.util.Map;
  
  /**
   * {@like ApplicationContext} 作为 Ioc 容器示例
   * @Classname IoCContainer
   * @Date 2022/11/2 13:29
   * @Created by ZhangXiao
   * @Description TODO
   *
   */
  public class AnnotationApplicationContextAsIoCContainerDemo {
        
        
  
      public static void main(String[] args) {
        
        
          // 创建 ApplicationContext 容器
          AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext();
          // 讲当前类 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);
      }
  
      /**
       * 通过 Java 注解的方式, 定义了一个 Bean
       * @return
       */
      @Bean
      public User user() {
        
        
          User user = new User();
          user.setId(1L);
          user.setName("xiaoge");
          return user;
      }
  
      /**
       * 根据类型查找集合对象
       * @param beanFactory
       */
      private static void lookupCollectionByType(BeanFactory beanFactory) {
        
        
          if (beanFactory instanceof ListableBeanFactory) {
        
        
              ListableBeanFactory listableBeanFactory = (ListableBeanFactory) beanFactory;
              Map<String, User> map = listableBeanFactory.getBeansOfType(User.class);
              System.out.println("查找到所有的 user 集合对象: " + map);
          }
      }
  }
  
  
  
  /*
  	运行结果
  		查找到所有的 user 集合对象: {user=User{id=1, name='xiaoge'}}
  */
  

• dependency-lookup-context.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"
         xsi:schemaLocation="http://www.springframework.org/schema/beans
          https://www.springframework.org/schema/beans/spring-beans.xsd">
  
  <!--    实施加载bean-->
      <bean id="user" class="org.xiaoge.thinking.in.spring.ioc.overview.domain.User">
          <property name="id" value="1" />
          <property name="name" value="xiaoge"/>
      </bean>
  
      <!-- 延迟bean 是沟通objectFactory简介创建的 -->
      <bean id="objectFactory" class="org.springframework.beans.factory.config.ObjectFactoryCreatingFactoryBean">
          <property name="targetBeanName" value="user" />
      </bean>
  
      <!-- parent继承 -->
      <bean id="superUser" class="org.xiaoge.thinking.in.spring.ioc.overview.domain.SuperUser" parent="user" primary="true">
          <property name="address" value="武汉" />
      </bean>
  
  </beans>