Java基础知识强化之集合框架笔记57：Map集合之HashMap集合（HashMap<Student，String>）的案例

 package cn.itcast_02;

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

public Student() {
super();
}

public Student(String name, int age) {
super();
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;
}

@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + age;
result = prime * result + ((name == null) ? 0 : name.hashCode());
return result;
}

@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
Student other = (Student) obj;
if (age != other.age)
return false;
if (name == null) {
if (other.name != null)
return false;
} else if (!name.equals(other.name))
return false;
return true;
}

}

 package cn.itcast_02;

import java.util.HashMap;
import java.util.Set;

/*
* HashMap<Student,String>
* 键：Student
*         要求：如果两个对象的成员变量值都相同，则为同一个对象。
* 值：String
*/
public class HashMapDemo4 {
public static void main(String[] args) {
// 创建集合对象
HashMap<Student, String> hm = new HashMap<Student, String>();

// 创建学生对象
Student s1 = new Student("貂蝉", 27);
Student s2 = new Student("王昭君", 30);
Student s3 = new Student("西施", 33);
Student s4 = new Student("杨玉环", 35);
Student s5 = new Student("貂蝉", 27);

// 添加元素
hm.put(s1, "8888");
hm.put(s2, "6666");
hm.put(s3, "5555");
hm.put(s4, "7777");
hm.put(s5, "9999");

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