package J20250723; import java.util.Comparator; import java.util.Set; import java.util.TreeMap; /** * @author WanJl * @version 1.0 * @title Demo07_TreeMap * @description * @create 2025/7/23 */ public class Demo07_TreeMap { public static void main(String[] args) { TreeMap map=new TreeMap((Comparator) (o1, o2) -> { int r=o2.getId()-o1.getId(); r=r==0?o1.getName().compareTo(o2.getName()):r; return r; }); Student s1=new Student(1001,"张三1"); Student s2=new Student(1002,"张三2"); Student s3=new Student(1003,"张三3"); Student s4=new Student(1004,"张三4"); map.put(s1,"北京"); map.put(s2,"上海"); map.put(s3,"广州"); map.put(s4,"深圳"); //获取key的集合 Set students = map.keySet(); for (Student s:students){ //get获取值 String addr = map.get(s); System.out.println(s+"->"+addr); } } }