java map 对key排序

map 对key排序

1 如果key为String类型 使用Treemap即可

TreeMap p = new TreeMap<>();

p.put("desc",100);

p.put("cdn",1000);

p.put("hight",900);

p.put("about",60);

System.out.println(new Gson().toJson(p));

 

 

因为string实现了

public final class String

implements java.io.Serializable, Comparable, CharSequence {

 

 

 

 

2 如果key为对象类型比如 k , 让k实现

extends Comparable>

 

public static , V > Map sortByKey(Map map) {

Map result = new LinkedHashMap<>();

Stream> st = map.entrySet().stream();

 

st.sorted (Comparator.comparing(e -> e.getKey() ))

.forEach(e -> result.put(e.getKey(), e.getValue()));

return result;

}