spring中bean的配置问题

package com.spring.DI;
public class IdRefTestBean {
	private String id;
	public String getId() {
		System.out.println("getter "+id);
		return id;
	}
	public void setId(String id) {
		System.out.println("setter "+id);
		this.id = id;
	}

}

清单2：配置文件src/config/diconfig.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"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd">
    <bean id = "bean1" class="java.lang.String">
    	<constructor-arg index="0" value="hello!"/>
    </bean>
    <bean id="bean2" class = "java.lang.String">
    	<constructor-arg index="0" value="world"/>
    </bean>
    <bean id = "idrefBean1" class="com.spring.DI.IdRefTestBean">
    	<property name="id">
    		<idref bean="bean1"/>
    
    	</property>
    
    </bean>
    
    
</beans>

清单3：junit测试
package com.spring.DI;
import static org.junit.Assert.*;
import org.junit.Test;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class DITest {
@Test
public void test() {
BeanFactory beanFactory = new ClassPathXmlApplicationContext(“config/diconfig.xml”);
IdRefTestBean idRefTestBean = beanFactory.getBean(“idrefBean1”,IdRefTestBean.class);
System.out.println(idRefTestBean.getId().toUpperCase());
String id = beanFactory.getBean(“bean1”,String.class);
System.out.println(id);
}
}
输出结果:
setter bean1
getter bean1
BEAN1
hello!
为什么这里获取到bean中的String类型的属性id的值不为设置的hello，而是bean的“bean1”？
求指导