Spring使用PropertyPathFactoryBean进行属性值注入

本文转自：http://www.blogjava.net/wangxinsh55/archive/2010/08/10/328427.html

实际应用中，某个实例的属性可能是另一个对象的一个属性，Spring支持将bean实例的属性值直接赋值给一个变量

属性值的注入，是通过PropertyPathFactoryBean完成的，PropertyPathFactoryBean用来获取目标bean的属性，获得的值可以注入到其他bean,也可以定义成新的bean

实体类：

public class Person {    private Son son;    private String age;        public Son getSon() {        return son;    }        public void setSon(Son son) {        this.son = son;    }        public String getAge() {        return age;    }        public void setAge(String age) {        this.age = age;    }}

public class Son {    private String age;    public String getAge() {        return age;    }    public void setAge(String age) {        this.age = age;    }}

配置文件：提供四种注入

<?xml version="1.0" encoding="GB2312"?><beans default-autowire="byName"xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:util="http://www.springframework.org/schema/util"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd        http://www.springframework.org/schema/util http://localhost:8080/schema/www.springframework.org/schema/util/spring-util-2.0.xsd "> <bean id="person" class="com.alibaba.chj.factorybean.Person" scope="prototype">     <property name="age">        <value>30</value>     </property>     <property name="son">        <bean class="com.alibaba.chj.factorybean.Son">           <property name="age">              <value>16</value>           </property>        </bean>     </property>  </bean>    <!--如下将会将person的属性son的属性age传入son1实例的age属性-->    <bean id="son1" class="com.alibaba.chj.factorybean.Son">        <property name="age">          <!--以下是访问bean属性的简单方式,这样可以将person这个bean的age属性赋值给son1这个bean的age属性-->                    <bean id="person.son.age" class="org.springframework.beans.factory.config.PropertyPathFactoryBean"/>        </property>    </bean>        <!-- 以下将会获得结果son,它将是person bean的son的数值-->    <bean id="son2" class="org.springframework.beans.factory.config.PropertyPathFactoryBean">       <property name="targetBeanName">         <value>person</value>       </property>       <property name="propertyPath">         <value>son</value>       </property>    </bean>         <!-- 以下将会获得结果16,它将是person bean的son的age属性-->    <bean id="son3" class="org.springframework.beans.factory.config.PropertyPathFactoryBean">       <property name="targetBeanName">         <value>person</value>       </property>       <property name="propertyPath">         <value>son.age</value>       </property>    </bean>        <!-- 以下会获得结果为30 ,它将是获得该bean的内部bean的age属性-->    <bean id="son4" class="org.springframework.beans.factory.config.PropertyPathFactoryBean">        <property name="targetObject">            <bean class="com.alibaba.chj.factorybean.Person">                <property name="age"><value>30</value></property>            </bean>        </property>        <property name="propertyPath"><value>age</value></property>    </bean></beans>

测试代码：

public class PropertyPathTest {    public static void main(String[] args) {        ApplicationContext context = new ClassPathXmlApplicationContext(                                                                        "com/alibaba/chj/factorybean/propertyPathFactoryBean.xml");        Son son1 = (Son) context.getBean("son1");        Son son2 = (Son) context.getBean("son2");        System.out.println("person age is:" + son1.getAge());        System.out.println("person age is:" + son2.getAge());        System.out.println(context.getBean("son3"));        System.out.println(context.getBean("son4"));    }}