Spring Bean继承解析
在 Spring XML 配置中,我们通过子 Bean 的 parent 属性来指定需要继承的父 Bean,配置格式如下。
<!--父Bean-->
<bean id="parentBean" class="xxx.xxxx.xxx.ParentBean" >
<property name="xxx" value="xxx"></property>
<property name="xxx" value="xxx"></property>
</bean>
<!--子Bean-->
<bean id="childBean" class="xxx.xxx.xxx.ChildBean" parent="parentBean"></bean>
spring bean 继承实例
创建一个名为 Animal 的类,代码如下。
package net.test;
public class Animal {
private String name;
private Integer age;
public void setName(String name) {
System.out.println("Animal setName:" + name);
this.name = name;
}
public void setAge(Integer age) {
System.out.println("Animal setAge:" + age);
this.age = age;
}
@Override
public String toString() {
return "Animal{" +
"name='" + name + '\'' +
", age=" + age +
'}';
}
}
创建一个名为 Dog 的类,代码如下。
package net.test;
public class Dog {
private String name;
private Integer age;
private String call;
public void setCall(String call) {
System.out.println("Dog setCall:" + call);
this.call = call;
}
public void setName(String name) {
System.out.println("Dog setName:" + name);
this.name = name;
}
public void setAge(Integer age) {
System.out.println("Dog setAge:" + age);
this.age = age;
}
@Override
public String toString() {
return "Dog{" +
"name='" + name + '\'' +
", age=" + age +
", call='" + call + '\'' +
'}';
}
}
在 src 目录下,创建 Spring 配置文件 Beans.xml,配置内容如下。
<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-3.0.xsd">
<bean id="animal" class="net.test.Animal">
<property name="name" value="动物"></property>
<property name="age" value="15"></property>
</bean>
<bean id="dog" class="net.test.Dog" parent="animal">
<property name="name" value="小狗"></property>
<property name="call" value="小狗叫"></property>
</bean>
</beans>
创建一个名为 MainApp 的类,代码如下。
package net.test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class MainApp {
public static void main(String[] args) {
//获取 ClassPathXmlApplicationContext 容器
ApplicationContext context = new ClassPathXmlApplicationContext("Beans.xml");
Dog dog = context.getBean("dog", Dog.class);
System.out.println(dog);
}
}
执行 MainApp 中的 main 方法,控制台输出如下。
Animal setName:动物
Animal setAge:15
Dog setName:小狗
Dog setAge:15
Dog setCall:小狗叫
Dog{name='小狗', age=15, call='小狗叫'}