已知目标json的所有key-value，以及key所属路径，生成json

例如：
"a.b.c":"v1"
"a.b.d":"v2"
"a.e":"v3"

生成json：
{
    "a":{
        "b":{
            "d":"v2",
            "c":"v1"
        },
        "e":"v3"
    }
}

代码如下：

package common.utils;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ObjectNode;

import java.util.HashMap;
import java.util.Map;

public class GenerateJsonUtils {

    public static void main(String[] args) throws JsonProcessingException {
        Map<String, String> data = new HashMap<>();
        data.put("a.b.c", "v1");
        data.put("a.b.d", "v2");
        data.put("a.e", "v3");
        System.out.println(generateJson(data));
    }

    public static String generateJson(Map<String, String> data) throws JsonProcessingException {
        ObjectMapper mapper = new ObjectMapper();
        ObjectNode rootNode = mapper.createObjectNode();
        for (Map.Entry<String, String> item : data.entrySet()) {
            buildJsonByPath(item.getKey(), item.getValue(), rootNode, mapper);
        }
        return mapper.writeValueAsString(rootNode);
    }

    private static void buildJsonByPath(String path, String value, ObjectNode rootNode, ObjectMapper mapper) {
        String[] arr = path.split("\\.");
        JsonNode ref = rootNode;
        JsonNode next;
        for (int i = 0; i < arr.length; i++) {
            next = ref.get(arr[i]);
            if (next == null) {
                if (i == arr.length - 1) {
                    ((ObjectNode) ref).put(arr[i], value);
                } else {
                    String[] copy = new String[arr.length - i - 1];
                    System.arraycopy(arr, i + 1, copy, 0, copy.length);
                    ObjectNode node = createObjectNode(copy, value, mapper);
                    ((ObjectNode) ref).set(arr[i], node);
                }
                break;
            }
            ref = next;
        }
    }

    private static ObjectNode createObjectNode(String[] arr, String value, ObjectMapper mapper) {
        if (arr.length == 1) {
            ObjectNode node = mapper.createObjectNode();
            node.put(arr[0], value);
            return node;
        }
        String[] copy = new String[arr.length - 1];
        System.arraycopy(arr, 1, copy, 0, copy.length);
        ObjectNode node = mapper.createObjectNode();
        node.set(arr[0], createObjectNode(copy, value, mapper));
        return node;
    }
}