Spring实战——容器后处理器

深碍√TFBOYSˉ_ 2021-07-24 23:23 321阅读 0赞

**一 配置文件**

<?xml version="1.0" encoding="GBK"?>
    <beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xmlns="http://www.springframework.org/schema/beans"
         xmlns:p="http://www.springframework.org/schema/p"
         xsi:schemaLocation="http://www.springframework.org/schema/beans
         http://www.springframework.org/schema/beans/spring-beans-4.0.xsd">
         
         <bean id="steelAxe"  class="org.crazyit.app.service.impl.SteelAxe"/>
         <bean id="chinese"  class="org.crazyit.app.service.impl.Chinese"
               init-method="init" p:name="孙悟空"  p:axe-ref="steelAxe"/>
         
         <bean id="beanFactoryPostProcessor"
               class="org.crazyit.app.util.MyBeanFactoryPostProcessor"/>
    </beans>

**二 接口**

Axe

package org.crazyit.app.service;
    
    public interface Axe
    {
         public String chop();
    }

Person

package org.crazyit.app.service;
    
    public interface Person
    {
         public void useAxe();
    }

**三 Bean**

Chinese

package org.crazyit.app.service.impl;
    
    
    import org.springframework.beans.factory.InitializingBean;
    import org.springframework.beans.BeansException;
    import org.springframework.beans.factory.config.BeanPostProcessor;
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.support.ClassPathXmlApplicationContext;
    
    
    import org.crazyit.app.service.*;
    
    public class Chinese
        implements Person,InitializingBean
    {
        private Axe axe;
        private String name;
        public Chinese()
        {
            System.out.println("Spring实例化主调bean：Chinese实例...");
        }
        public void setAxe(Axe axe)
        {
            this.axe = axe;
        }
        public void setName(String name)
        {
            System.out.println("Spring执行setName()方法注入依赖关系...");
            this.name = name;
        }
        public void useAxe()
        {
            System.out.println(name + axe.chop());
        }
        // 下面是两个生命周期方法
        public void init()
        {
            System.out.println("正在执行初始化方法 init...");
        }
        public void afterPropertiesSet() throws Exception
        {
            System.out.println("正在执行初始化方法 afterPropertiesSet...");
        }
    }

SteelAxe

package org.crazyit.app.service.impl;
    import org.crazyit.app.service.*;
    
    public class SteelAxe
         implements Axe
    {
         public SteelAxe()
         {
               System.out.println("Spring实例化依赖bean：SteelAxe实例...");
         }
         public String chop()
         {
               return "钢斧砍柴真快";
         }
    }

**四 容器后处理器**

package org.crazyit.app.util;
    
    
    import org.springframework.beans.BeansException;
    import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
    import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
    
    
    public class MyBeanFactoryPostProcessor
        implements BeanFactoryPostProcessor
    {
        /**
         * 重写该方法，对Spring进行后处理。
         * @param beanFactory Spring容器本身
         */
        public void postProcessBeanFactory(
            ConfigurableListableBeanFactory beanFactory)
            throws BeansException
        {
            System.out.println("程序对Spring所做的BeanFactory的初始化没有改变...");
            System.out.println("Spring容器是：" + beanFactory);
        }
    }

**五 测试类**

package lee;
    
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.support.ClassPathXmlApplicationContext;
    
    
    import org.crazyit.app.service.*;
    
    public class BeanTest
    {
        public static void main(String[] args)
        {
            // 以ApplicationContex作为Spring容器
            // 它会自动注册容器后处理器、Bean后处理器
            ApplicationContext ctx = new
                ClassPathXmlApplicationContext("beans.xml");
            Person p = (Person)ctx.getBean("chinese");
            p.useAxe();
        }
    }

**六 测试结果**

程序对Spring所做的BeanFactory的初始化没有改变...
    Spring容器是：org.springframework.beans.factory.support.DefaultListableBeanFactory@6a024a67: defining beans  [steelAxe,chinese,beanFactoryPostProcessor]; root of factory  hierarchy
    Spring实例化依赖bean：SteelAxe实例...
    Spring实例化主调bean：Chinese实例...
    Spring执行setName()方法注入依赖关系...
    正在执行初始化方法  afterPropertiesSet...
    正在执行初始化方法   init...
    孙悟空钢斧砍柴真快