public class Student {   //学生实体类private  String   name;  //姓名private  Integer  age;  //年龄private  Grade   grade;  //年级
    @Overridepublic String toString() {return "Student [name=" + name + ", age=" + age + ", grade=" + grade+ "]";}public Student() {super();}public Student(String name, Integer age) {super();this.name = name;this.age = age;}public String getName() {return name;}//  set（）  DI 依赖注入public void setName(String name) {this.name = name;}public Integer getAge() {return age;}public void setAge(Integer age) {this.age = age;}public Grade getGrade() {return grade;}public void setGrade(Grade grade) {this.grade = grade;}}

public class Grade {   //年级实体类private String  name;  //年级名称
@Overridepublic String toString() {return "Grade [name=" + name + "]";}public Grade() {super();}public Grade(String name) {super();this.name = name;}public String getName() {return name;}public void setName(String name) {this.name = name;}}

<?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/beanshttp://www.springframework.org/schema/beans/spring-beans.xsd"><!-- 配置Grade 类的bean  01.设值注入  保证类中有属性对应的set（）即可 --><bean id="grade" class="cn.bdqn.bean.Grade"><!-- name的属性值  默认使用DI 查询类中的setName() --><property name="name" value="1年级"/></bean><!--  配置学生Bean   实例化学生对象   默认执行的是无参构造 --><bean id="student" class="cn.bdqn.bean.Student"><property name="name" value="小马"/><property name="age" value="50"/><!-- 对类中的域属性  赋值  使用ref --><property name="grade" ref="grade"/></bean>
</beans>

public class StudentTest {@Testpublic  void  test01(){ApplicationContext context=new ClassPathXmlApplicationContext("applicationContext.xml");/** 获取容器给我们创建的Student对象   ioc的体现*  本身由自身创建对象的过程，把创建对象的权利移交给了spring容器!  IOC  控制反转* * 之前 Student student=new Student();* 现在context.getBean("student");* context容器来创建对象了* */Student student=(Student) context.getBean("student");System.out.println(student);}
}

public class Student {   //学生实体类private  String   name;  //姓名private  Integer  age;  //年龄private  Grade   grade;  //年级
    @Overridepublic String toString() {return "Student [name=" + name + ", age=" + age + ", grade=" + grade+ "]";}//带参构造public Student(String name, Integer age, Grade grade) {super();this.name = name;this.age = age;this.grade = grade;}}

<?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/beanshttp://www.springframework.org/schema/beans/spring-beans.xsd"><!-- 配置Grade 类的bean --><bean id="grade" class="cn.bdqn.bean.Grade"><!-- name的属性值  默认使用DI 查询类中的setName() --><property name="name" value="1年级"/></bean><!-- 02.构造注入    调用带参构造来创建对象的实例保证类中有相应的带参构造    set（）和无参构造 都可以 消失了...  --><bean id="student" class="cn.bdqn.bean.Student"><!-- 001.使用参数下标<constructor-arg  index="0" value="小马"/><constructor-arg  index="1" value="50"/><constructor-arg  index="2" ref="grade"/> --><!--002.按照参数的顺序   必须和参数顺序 一致 <constructor-arg   value="小马1"/><constructor-arg   value="501"/><constructor-arg   ref="grade"/> --><!--003.使用构造参数名称 不是全局变量      进行注入   推荐使用 --><constructor-arg  name="name" value="小马2"/><constructor-arg  name="age"  value="502"/><constructor-arg  name="grade" ref="grade"/></bean></beans>

public class Student {   //学生实体类private  String   name;  //姓名private  Integer  age;  //年龄private  Grade   grade;  //年级@Overridepublic String toString() {return "Student [name=" + name + ", age=" + age + ", grade=" + grade+ "]";}// p 注入的时候需要public Student() {super();}//带参构造public Student(String name, Integer age, Grade grade) {super();this.name = name;this.age = age;this.grade = grade;}//p 必须要有set（）public String getName() {return name;}public void setName(String name) {this.name = name;}public Integer getAge() {return age;}public void setAge(Integer age) {this.age = age;}public Grade getGrade() {return grade;}public void setGrade(Grade grade) {this.grade = grade;}}

Student实体类

<?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"  xmlns:c="http://www.springframework.org/schema/c"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsd"><!-- 配置Grade 类的bean --><bean id="grade" class="cn.bdqn.bean.Grade"><!-- name的属性值  默认使用DI 查询类中的setName() --><property name="name" value="1年级"/></bean><!-- 03.使用p命名空间注入   必须有set()和 无参构造函数 <bean id="student" class="cn.bdqn.bean.Student" p:name="小马哥" p:age="50" p:grade-ref="grade"/>--><!-- 04.使用c命名空间注入 必须要有对应的带参构造  --><bean id="student" class="cn.bdqn.bean.Student" c:name="小马哥" c:age="50" c:grade-ref="grade"/>
</beans>

applicationContext.xml