HashMap存儲自定義對象學習筆記
阿新 • • 發佈:2018-10-24
etc 對象學習 lse sta () static final 存儲 深圳 學生對象
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; //以年齡為主要條件 return num == 0 ? this.name.compareTo(o.name) : num; } }
hasMap類
/* * * A:案例演示 * HashMap集合鍵是Student值是String的案例 * 鍵是學生對象,代表每一個學生 * 值是字符串對象,代表學生歸屬地 */ public static void main(String[] args) { HashMap<Student, String> hm = new HashMap<>(); hm.put(new Student("張三", 23), "北京"); hm.put(new Student("張三", 23), "上海"); hm.put(new Student("李四", 24), "廣州"); hm.put(new Student("王五", 25), "深圳"); System.out.println(hm); }
HashMap存儲自定義對象學習筆記