HashMap存储自定义对象学习笔记

学生对象

public class Student implements Comparable<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 String toString() {
		return "Student [name=" + name + ", 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;
	}
	@Override
	public int compareTo(Student o) {
		int num = this.age - o.age;					//以年龄为主要条件
		return num == 0 ? this.name.compareTo(o.name) : num;
	}
}

hasMap类

/*
	 * * A:案例演示
	 * HashMap集合键是Student值是String的案例
	 * 键是学生对象,代表每一个学生
	 * 值是字符串对象,代表学生归属地
	 */
	public static void main(String[] args) {
		HashMap<Student, String> hm = new HashMap<>();
		hm.put(new Student("张三", 23), "北京");
		hm.put(new Student("张三", 23), "上海");
		hm.put(new Student("李四", 24), "广州");
		hm.put(new Student("王五", 25), "深圳");
		
		System.out.println(hm);
	}