Java框架spring 学习笔记（五）：Bean定义继承

子 bean 的定义继承父定义的配置数据。子定义可以根据需要重写一些值，或者添加其他值。

编写HelloWorld.java

 package com.example.spring;

 public class HelloWorld {
     private String message1;
     private String message2;
     public void setMessage1(String message){
         this.message1  = message;
     }
     public void setMessage2(String message){
         this.message2  = message;
     }

     public void getMessage1(){
         System.out.println("Your Message1 : " + message1);
     }
     public void getMessage2(){
         System.out.println("Your Message2 : " + message2);
     }
 }

编写HelloSpring.java

 package com.example.spring;

 public class HelloSpring {
     private String message1;
     private String message2;
     private String message3;

     public void setMessage1(String message){
         this.message1 = message;
     }

     public void setMessage2(String message){
         this.message2 = message;
     }

     public void setMessage3(String message){
         this.message3 = message;
     }

     public void getMessage1(){
         System.out.println("Spring Message1 : " + message1);
     }

     public void getMessage2(){
         System.out.println("Spring Message2 : " + message2);
     }

     public void getMessage3(){
         System.out.println("Spring Message3 : " + message3);
     }
 }

编写Beans.xml，使用parent属性将“helloSpring”定义为“helloWorld”的子Bean，这个子Bean继承message2的属性，重写message1的属性，并且引入一个属性message3。

 <?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 id="helloWorld" class="com.example.spring.HelloWorld">
         <property name="message1" value="Hello World : message1"></property>
         <property name="message2" value="Hello World : message2"/>
     </bean>

     <bean id="helloSpring" class="com.example.spring.HelloSpring" parent="helloWorld">
         <property name="message1" value="Hello Spring : message1"/>
         <property name="message3" value="Hello Spring : message3"/>
     </bean>

 </beans>

编写Application.java

 package com.example.spring;

 import org.springframework.context.support.AbstractApplicationContext;
 import org.springframework.context.support.ClassPathXmlApplicationContext;

 public class Application {
     public static void main(String[] args) {
         //bean配置文件所在位置 D:\\IdeaProjects\\spring\\src\\Beans.xml
         //使用AbstractApplicationContext容器
         AbstractApplicationContext context = new ClassPathXmlApplicationContext("file:D:\\IdeaProjects\\spring\\src\\Beans.xml");
         HelloWorld objA = (HelloWorld)context.getBean("helloWorld");
         objA.getMessage1();
         objA.getMessage2();

         HelloSpring objB = (HelloSpring) context.getBean("helloSpring");
         objB.getMessage1();
         objB.getMessage2();
         objB.getMessage3();
     }
 }

运行输出

Your Message1 : Hello World : message1
Your Message2 : Hello World : message2
Spring Message1 : Hello Spring : message1
Spring Message2 : Hello World : message2
Spring Message3 : Hello Spring : message3