Spring Bean继承

通过使用 bean parent 属性,我们可以指定Bean之间的继承关系。在这种情况下,父bean的值将被继承到当前bean。

让我们看一下继承bean的简单示例。

Employee.java

此该类包含三个属性,三个构造函数和用于显示值的show()方法。

package com.nhooo;
public class Employee {
private int id;
private String name;
private Address address;
public Employee() {}
public Employee(int id, String name) {
    super();
    this.id = id;
    this.name = name;
}
public Employee(int id, String name, Address address) {
    super();
    this.id = id;
    this.name = name;
    this.address = address;
}
void show(){
    System.out.println(id+" "+name);
    System.out.println(address);
}
}

Address.java

package com.nhooo;
public class Address {
private String addressLine1,city,state,country;
public Address(String addressLine1, String city, String state, String country) {
    super();
    this.addressLine1 = addressLine1;
    this.city = city;
    this.state = state;
    this.country = country;
}
public String toString(){
    return addressLine1+" "+city+" "+state+" "+country;
}
}

applicationContext.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="e1" class="com.nhooo.Employee">
<constructor-arg value="101"></constructor-arg>
<constructor-arg  value="Sachin"></constructor-arg>
</bean>
<bean id="address1" class="com.nhooo.Address">
<constructor-arg value="21,Lohianagar"></constructor-arg>
<constructor-arg value="Ghaziabad"></constructor-arg>
<constructor-arg value="UP"></constructor-arg>
<constructor-arg value="USA"></constructor-arg>
</bean>
<bean id="e2" class="com.nhooo.Employee" parent="e1">
<constructor-arg ref="address1"></constructor-arg>
</bean>
</beans>

Test.java

此类从applicationContext.xml文件获取Bean并调用show方法。

package com.nhooo;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
public class Test {
public static void main(String[] args) {
    Resource r=new ClassPathResource("applicationContext.xml");
    BeanFactory factory=new XmlBeanFactory(r);
    
    Employee e1=(Employee)factory.getBean("e2");
    e1.show();
    
}
}