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

 1 package com.example.spring;
 2 
 3 public class HelloWorld {
 4     private String message1;
 5     private String message2;
 6     public void setMessage1(String message){
 7         this.message1  = message;
 8     }
 9     public void setMessage2(String message){
10         this.message2  = message;
11     }
12 
13     public void getMessage1(){
14         System.out.println("Your Message1 : " + message1);
15     }
16     public void getMessage2(){
17         System.out.println("Your Message2 : " + message2);
18     }
19 }

编写HelloSpring.java

 1 package com.example.spring;
 2 
 3 public class HelloSpring {
 4     private String message1;
 5     private String message2;
 6     private String message3;
 7 
 8     public void setMessage1(String message){
 9         this.message1 = message;
10     }
11 
12     public void setMessage2(String message){
13         this.message2 = message;
14     }
15 
16     public void setMessage3(String message){
17         this.message3 = message;
18     }
19 
20     public void getMessage1(){
21         System.out.println("Spring Message1 : " + message1);
22     }
23 
24     public void getMessage2(){
25         System.out.println("Spring Message2 : " + message2);
26     }
27 
28     public void getMessage3(){
29         System.out.println("Spring Message3 : " + message3);
30     }
31 }

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。

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <beans xmlns="http://www.springframework.org/schema/beans"
 3        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 4        xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
 5 
 6     <bean id="helloWorld" class="com.example.spring.HelloWorld">
 7         <property name="message1" value="Hello World : message1"></property>
 8         <property name="message2" value="Hello World : message2"/>
 9     </bean>
10 
11     <bean id="helloSpring" class="com.example.spring.HelloSpring" parent="helloWorld">
12         <property name="message1" value="Hello Spring : message1"/>
13         <property name="message3" value="Hello Spring : message3"/>
14     </bean>
15 
16 </beans>

编写Application.java

 1 package com.example.spring;
 2 
 3 import org.springframework.context.support.AbstractApplicationContext;
 4 import org.springframework.context.support.ClassPathXmlApplicationContext;
 5 
 6 public class Application {
 7     public static void main(String[] args) {
 8         //bean配置文件所在位置 D:\IdeaProjects\spring\src\Beans.xml
 9         //使用AbstractApplicationContext容器
10         AbstractApplicationContext context = new ClassPathXmlApplicationContext("file:D:\IdeaProjects\spring\src\Beans.xml");
11         HelloWorld objA = (HelloWorld)context.getBean("helloWorld");
12         objA.getMessage1();
13         objA.getMessage2();
14 
15         HelloSpring objB = (HelloSpring) context.getBean("helloSpring");
16         objB.getMessage1();
17         objB.getMessage2();
18         objB.getMessage3();
19     }
20 }

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