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HashMap集合存储学生对象并遍历

news 2025/7/25 8:46:19

需求：创建一个HashMap集合，键是学生对象（Student）,值是居住地。存储多个键值对元素，并遍历。

要求保证键的唯一性：如果学生对象的成员变量值相同，我们就认为是同一个对象

思路：

定义学生类

创建HashMap集合对象

创建学生对象

把学生添加到集合

遍历集合

在学生类中重写两个方法

hashCode()

equals()

代码实现：

编写Student类

package com.aynu3;import java.util.Objects;public class Student {private String name;private 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;}@Overridepublic boolean equals(Object o) {if (this == o) return true;if (o == null || getClass() != o.getClass()) return false;Student student = (Student) o;if (age != student.age) return false;return Objects.equals(name, student.name);}@Overridepublic int hashCode() {int result = name != null ? name.hashCode() : 0;result = 31 * result + age;return result;}
}

package com.aynu3;import java.util.HashMap;
import java.util.Set;public class HashMapDemo {public static void main(String[] args) {//创建HashMap集合对象HashMap<Student,String> hm=new HashMap<Student,String>();//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);Student s4=new Student("王祖贤",33);//把学生添加到集合hm.put(s1,"西安");hm.put(s2,"武汉");hm.put(s3,"洛阳");hm.put(s4,"北京");//遍历集合Set<Student> keySet = hm.keySet();for (Student key:keySet) {String value = hm.get(key);System.out.println(key.getName() + "," + key.getAge()+","+value);}}
}