Spring4.0学习笔记(3) —— Spring_Bean之间的关系

1、继承关系

bean-relation.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans
    xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:p="http://www.springframework.org/schema/p"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">

    <bean id="address" class="com.spring.relation.Address">
        <property name="city" value="beijing^"></property>
        <property name="location" value="los angles"></property>
    </bean>
    
    <bean id="address2" parent="address">
        <property name="location" value="new York"></property>
    </bean>
</beans>

Address.java

package com.spring.autowire;

public class Address {
    private String city;
    private String location;
    public String getCity() {
        return city;
    }
    public void setCity(String city) {
        this.city = city;
    }
    public String getLocation() {
        return location;
    }
    public void setLocation(String location) {
        this.location = location;
    }
    @Override
    public String toString() {
        return "Address [city=" + city + ", location=" + location + "]";
    }
}

测试

package com.spring.relation;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class main {
    public static void main(String[] args) {
        ApplicationContext ctx = new ClassPathXmlApplicationContext("bean-relation.xml");
        Address address = (Address)ctx.getBean("address");
        System.out.println(address);
        
        Address address2 = (Address)ctx.getBean("address2");
        System.out.println(address2);
    
    }
}

【拓展】 abstract = true的时候，该bean是无法被实例化的。可以去掉用于实例化的class 属性，这样该bean仅为模板bean

    <bean id="address" class="com.spring.relation.Address" abstract="true">
        <property name="city" value="beijing^"></property>
        <property name="location" value="los angles"></property>
    </bean>
    
    <bean id="address2" parent="address">
        <property name="location" value="new York"></property>
    </bean>