package Impl; public class Teacher { public Teacher(){ } public Teacher(String name,Student student){ } }
package Impl; public class Student { private Teacher teacher; //Teacher类型 // private IPhone phone; private String teacherId; //String类型 public Student(){ } public Student(Teacher teacher){ this.teacher = teacher; } public Teacher getTeacher() { return teacher; } public void setTeacher(Teacher teacher) { this.teacher = teacher; } public String getTeacherId() { return teacherId; } public void setTeacherId(String teacherId) { this.teacherId = teacherId; } }
<?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-3.1.xsd" > <bean id="student" class="Impl.Student" > <property name="teacher"> <ref bean="teacher"/> </property> <property name="teacherId"> <idref bean="teacher"/> </property> </bean> <bean id="teacher" class="Impl.Teacher"> <constructor-arg index="0" type="java.lang.String"> <value>Morgan</value> </constructor-arg> <constructor-arg index="1" ref="student"> </constructor-arg> </bean> </beans>
package test; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; import Impl.Student; public class TestConstructorBeans { public static void main(String args[]){ ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("beans.xml"); // context.getBean("teacher"); ApplicationContext context2 = new ClassPathXmlApplicationContext(new String[]{"constructorBeans.xml"},context); //context.getBean("phone2"); Student s = (Student)context2.getBean("student"); System.out.println(s.getTeacherId()); } }
需要指出的是,<idref bean="teacher"/> 可以用<value>teacher</value>替代,但是Spring是不会检出value是否存在的。。而是用idref, sping在加载的时候会检出idref的值是否存在。 因为拿到另一个bean的id, 基本上都是想在运行时通过getBean得到bean的实例。