Java集合類排序方式之一
阿新 • • 發佈:2018-12-11
package com.hyn; import java.util.ArrayList; import java.util.Collections; import java.util.HashMap; import java.util.List; import java.util.Map; public class DemoCollect { public static void main(String[] args) { Map<String, String> map = new HashMap<>(); map.put("d", "d"); map.put("k", "k"); map.put("c", "c"); map.put("a", "a"); map.put("y", "y"); List<String> keys = new ArrayList<String>(map.keySet()); System.out.println(keys.toString());//[d, c, a, k, y] //集合類排序 Collections.sort(keys); System.out.println(keys.toString());//[a, c, d, k, y] } }