package entity;

public class Student {
    private String name;//学员姓名
    private String sex;//学员性别
    
    public Student(){
        
    }
    public Student(String name,String sex){
        this.name = name;
        this.sex = sex;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getSex() {
        return sex;
    }
    public void setSex(String sex) {
        this.sex = sex;
    }
    
}

package test;

import java.util.HashMap;
import java.util.Map;

import entity.Student;

public class HashMapDemo {
        public static void main(String[] args) {
            //1.创建学员对象
            Student student1 = new Student("哪吒","男");
            Student student2 = new Student("木吒","男");
            Student student3 = new Student("莉莉","女");
            //2.创建保存“键-值对" 的集合对象
            Map students = new HashMap();
            //3.把英文名称与学员对象按照“键- 值对”的方式存储在HashMap中
            students.put("Naza",student1);
            students.put("Muza",student2);
            students.put("Lili",student3);
            //4.打印键集
            System.out.println("键集："+students.keySet());
            //5.打印值集
            System.out.println("值集："+students.values());
            //6.打印键-值对集合
            System.out.println("键-值对集合："+students);
            
            String key = "Jack";
            //7.判断是否存在“Jack”这个键
            if(students.containsKey(key)){
                Student student = (Student)students.get(key);
                System.out.println(key+"对应的学员姓名是："+student.getName()+";性别是："+student.getSex());
            }
        }
}