package com.test.Test11; import java.util.*; public class Test02 { public static void main(String[] args) { /* * 增加:put(K key,V value) * 删除:clear() remove(Object key) * 修改: * 查看:entrySet() get(Object key) keySet() size() values() * 判断:containsKey(Object key) containsValue(Object value) * equals(Object o) isEmpty() * */ //TreeMap 唯一,有序(按升序或者降序排序) TreeMap<String, Integer> map = new TreeMap<>(); map.put("blili", 1234); map.put("alili", 2345); map.put("blili", 5467); map.put("clili", 5678); map.put("dlili", 2345); System.out.println(map.size()); //4(上面的添加了5对数据,只出来4对数据) System.out.println(map); //{alili=2345, blili=5467, clili=5678, dlili=2345} } }