package com.example;

import java.util.Arrays;
import java.util.HashMap;
import java.util.List;

import com.google.gson.GsonBuilder;

public class x {
@SuppressWarnings("unchecked")
public static void main(String[] args) {
List<String> list = Arrays.asList("中国 广州", "中国 浙江 杭州");
HashMap<String, Object> root = new HashMap<>();
for (String s : list) {
HashMap<String, Object> node = root;
String[] ss = s.split(" ");
for (int i = 0; i < ss.length; i++) {
HashMap<String, Object> subNode = (HashMap<String, Object>) node.get(ss[i]);
if (subNode == null) {
subNode = new HashMap<>();
node.put(ss[i], subNode);
}
node = subNode;
}
}
System.out.println(new GsonBuilder()
.setPrettyPrinting()
.serializeNulls()
.create().toJson(root));
}
}