Spring实战——依赖关系注入之后的行为

矫情吗；* 2021-07-24 19:48 321阅读 0赞

**一 配置**

<?xml version="1.0" encoding="GBK"?>
    <beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xmlns="http://www.springframework.org/schema/beans"
         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">
               <property name="axe" ref="steelAxe"/>
         </bean>
    </beans>

**二 接口**

1 Axe

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

2 Person

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

**三 Bean**

1 Chinese

package org.crazyit.app.service.impl;
    
    
    import org.springframework.beans.factory.InitializingBean;
    import org.springframework.beans.factory.*;
    import org.springframework.context.*;
    import org.crazyit.app.service.*;
    
    public class Chinese implements Person , InitializingBean
        , BeanNameAware, ApplicationContextAware
    {
        private Axe axe;
        public void setBeanName(String beanName)
        {
            System.out.println("===setBeanName===");
        }
        public void setApplicationContext(ApplicationContext ctx)
        {
            System.out.println("===setApplicationContext===");
        }
        public Chinese()
        {
            System.out.println("Spring实例化主调bean：Chinese实例...");
        }
        // axe的setter方法
        public void setAxe(Axe axe)
        {
            System.out.println("Spring调用setAxe()执行依赖注入...");
            this.axe = axe;
        }
        public void useAxe()
        {
            System.out.println(axe.chop());
        }
        // 测试用的初始化方法
        public void init()
        {
            System.out.println("正在执行初始化方法 init...");
        }
        // 实现InitializingBean接口必须实现的方法
        public void afterPropertiesSet() throws Exception
        {
            System.out.println("正在执行初始化方法 afterPropertiesSet...");
        }
    }

2 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 测试类**

package lee;
    
    
    import org.springframework.context.*;
    import org.springframework.context.support.*;
    
    
    import org.crazyit.app.service.*;
    
    public class BeanTest
    {
        public static void main(String[] args)throws Exception
        {
            ApplicationContext ctx = new
                ClassPathXmlApplicationContext("beans.xml");
            Person p = ctx.getBean("chinese" , Person.class);
            p.useAxe();
        }
    }

**五 测试结果**

Spring实例化依赖bean：SteelAxe实例...
    Spring实例化主调bean：Chinese实例...
    Spring调用setAxe()执行依赖注入...
    ===setBeanName===
    ===setApplicationContext===
    正在执行初始化方法 afterPropertiesSet...
    正在执行初始化方法 init...
    钢斧砍柴真快