常用的List,Set,Map容器以及比较器

import java.util.Arrays;public class User implements Comparable { private String id; private int age; public User(String id, int age) { this.id = id; this.age = age; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public String getId() { return id; } public void setId(String id) { this.id = id; } //实现Comparable接口需要实现此方法，此例类中比较年龄 public int compareTo(Object o) { return this.age - ((User) o).getAge(); }}