Java案例之HashMap集合存储学生对象并遍历

public class StudentDemo {
    public static void main(String[] args) {
        //创建Map集合对象
        Map<String,Student> m=new HashMap<String,Student>();
        //添加键值对
        m.put("01",new Student("张三"));
        m.put("04",new Student("赵六"));
        m.put("02",new Student("李四"));
        m.put("03",new Student("王五"));
        //遍历集合
        Set<Map.Entry<String,Student>> s= m.entrySet();
        //遍历
        for (Map.Entry<String,Student> ss:s){
            //根据键值对对象获取值和key
            String key=ss.getKey();
           Student value=ss.getValue();
            System.out.println(key+","+value.getName());
        }
        System.out.println("------------------------");
        //方式二，通过键找值
        Set<String> m1=m.keySet();
        for (String key :m1){
             Student student =m.get(key);
            System.out.println(key+","+student.getName());
        }
    }
}

public class StudentDemo {
    public static void main(String[] args) {
        //创建集合对象
        Map<Student,String> m=new HashMap<Student,String>();
        //添加键值对
        m.put(new Student("张三",18),"上海");
        m.put(new Student("李四",19),"北京");
        m.put(new Student("王五",20),"上海");
        m.put(new Student("王五",20),"海南");
        //方式一
        //获取所有键值对的集合
        Set<Map.Entry<Student,String>> s=m.entrySet();
        //方式一、遍历
        for (Map.Entry<Student,String> mm:s){
            //通过键值对获取对应的值与键
            Student key=mm.getKey();
            String value=mm.getValue();
            System.out.println(key.getName()+","+key.getAge()+value);
        }
        System.out.println("---------------------------------");
        //方式二
        Set<Student> key=m.keySet();
        for (Student s1:key){
            String value=m.get(s1);
            System.out.println(s1.getName()+","+s1.getAge()+","+value);
        }
    }
}