Spring6梳理12——依赖注入之注入Map集合类型属性

news2024/11/15 8:50:26

以上笔记来源：
尚硅谷Spring零基础入门到进阶，一套搞定spring6全套视频教程（源码级讲解）https://www.bilibili.com/video/BV1kR4y1b7Qc

12 依赖注入之注入Map集合类型属性

12.1 创建Student类和Teacher类

Student类中创建了run方法，展示了被注入的普通属性和map属性的值

Teacher类则创建了map类型的getter,setter方法以及方便输出的tostring方法

package com.atguigu.spring6.iocxml.dimap;

import java.util.Map;

/**
 * @package: com.atguigu.spring6.iocxml.dimap
 * @className: Student
 * @Description:
 * @author: haozihua
 * @date: 2024/8/20 15:20
 */
public class Student {


    //一个学生对应很多个老师，一个老师也可以对应很多个学生
      
    private Map<String,Teacher> teacherMap;

    private String sid;
    private String sname;

    public String getSid() {
        return sid;
    }

    public void setSid(String sid) {
        this.sid = sid;
    }

    public String getSname() {
        return sname;
    }

    public void setSname(String sname) {
        this.sname = sname;
    }

    public Map<String, Teacher> getTeacherMap() {
        return teacherMap;
    }

    public void setTeacherMap(Map<String, Teacher> teacherMap) {
        this.teacherMap = teacherMap;
    }


    public void run() {
        System.out.println("学生编号： " + sid + " " + "学生名称：" + sname);
        System.out.println(teacherMap);
    }
}

package com.atguigu.spring6.iocxml.dimap;

/**
 * @package: com.atguigu.spring6.iocxml.dimap
 * @className: Teacher
 * @Description:
 * @author: haozihua
 * @date: 2024/8/20 15:21
 */
public class Teacher {
        private Integer teacherId;
        private String teacherName;

        public Integer getTeacherId() {
                return teacherId;
        }

        public void setTeacherId(Integer teacherId) {
                this.teacherId = teacherId;
        }

        public String getTeacherName() {
                return teacherName;
        }

        public void setTeacherName(String teacherName) {
                this.teacherName = teacherName;
        }

        @Override
        public String toString() {
                return "Teacher{" +
                        "teacherId=" + teacherId +
                        ", teacherName='" + teacherName + '\'' +
                        '}';
        }

        public Teacher(Integer teacherId, String teacherName) {
                this.teacherId = teacherId;
                this.teacherName = teacherName;
        }
        public Teacher() {

        }

}

12.2 创建XML配置文件

由于在Student类中创建了关于Teacher类的map集合，因此在student的bean中配置信息，首先创建普通类型属性，根据实体类中的变量名称，设置name属性值

之后创建Map集合类型属性时，注意entry>key>value或者ref标签的嵌套

<?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">
    <!--
        1.创建两个类
        2.注入普通类型属性
        3.在学生bean注入map集合类型属性
    -->
    <bean id="teacherone" class="com.atguigu.spring6.iocxml.dimap.Teacher">
        <property name="teacherId" value="100"></property>
        <property name="teacherName" value="西门庆"></property>
    </bean>

    <bean id="teachertwo" class="com.atguigu.spring6.iocxml.dimap.Teacher">
        <property name="teacherId" value="200"></property>
        <property name="teacherName" value="东方不败"></property>
    </bean>

    <bean id="student" class="com.atguigu.spring6.iocxml.dimap.Student">
        <property name="sid" value="2000"></property>
        <property name="sname" value="李四"></property>
        <property name="teacherMap">
            <map>
                <entry>
                    <key>
                        <value>10010</value>
                    </key>
                    <ref bean="teacherone"></ref>
                </entry>

                <entry>
                    <key>
                        <value>210</value>
                    </key>
                    <ref bean="teachertwo"></ref>
                </entry>
            </map>
        </property>
    </bean>
</beans>

12.3 创建测试类方法

    @Test
    public void TestStu(){
        ApplicationContext context =
                new ClassPathXmlApplicationContext("bean-dimap.xml");
        Student student = context.getBean("student",Student.class);
        student.run();
    }