创建学生类对象

public class Student {
    private String name;
    public int age ;

    public Student() {
    }

    public Student(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
}

测试类对象

public class MapDemo {
    public static void main(String[] args) {
        /**
         * 需求：创建一个HashMap集合，键是学号（String），值是学生对象（String）。
         * 存储三个键值对，并遍历
         * 思路：
         * 1.定义学生类
         * 2.创建HashMap集合对象
         * 3.创建学生对象
         * 4.把学生添加到集合
         * 5.遍历集合：方式1：键找值，方式2：键值对对象找键和值
         */

        //创建HashMap集合对象
        HashMap<String, Student> hm = new HashMap<>();

        //创建学生对象
        Student s1 = new Student("林青霞", 30);
        Student s2 = new Student("张曼玉", 35);
        Student s3 = new Student("王祖贤", 33);

        //把学生添加到集合
        hm.put("1",s1);
        hm.put("2",s2);
        hm.put("3",s3);

        //方式1
        Set<String> keySet = hm.keySet();
        for (String key:keySet){
            Student value = hm.get(key);
            System.out.println(key+","+value.getName()+","+value.getAge());
        }
        System.out.println("--------------");

        //方式2
        Set<Map.Entry<String, Student>> entrySet = hm.entrySet();
        for (Map.Entry<String, Student> me:entrySet){
            String key = me.getKey();
            Student value = me.getValue();
            System.out.println(key+","+value.getName()+","+value.getAge());
        }

    }
}

运行结果