28.使用泛型根据学员英文名找到学员对象

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 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // 1、创建学员对象
        Student student1 = new Student("李明", "男");
        Student student2 = new Student("刘丽", "女");
        // 2、创建保存“键-值对”的集合对象
        Map<String,Student> students = new HashMap<String,Student>();
        // 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("Jack", student1);
        students.put("Rose", student2);
        // 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)){
            // 8、如果存在，根据键获取相应的值
            Student  student = students.get(key);
            System.out.println("学员姓名："+student.getName());
        }


    }

}