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