如何遍历JsonNode对象的所有子节点并提取price字段明细信息

以下针对Jackson框架下JsonNode节点遍历提取price明细的需求，提供两种适配不同场景的实现方式：

场景1：已知JSON结构，精准提取（性能最优，推荐） #

你提供的响应报文结构固定，可直接按层级定位到商品集合节点遍历，代码实现如下：

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

// 定义Price明细存储类
class PriceDetail {
    private String itemId;
    private Double amount;
    private Double baseAmount;

    public PriceDetail(String itemId, Double amount, Double baseAmount) {
        this.itemId = itemId;
        this.amount = amount;
        this.baseAmount = baseAmount;
    }
    // 按需补充getter、setter方法
}

public class ExtractPriceDemo {
    public static void main(String[] args) throws Exception {
        // 这里替换为你的实际响应报文字符串
        String response = "{\n  \"content\": {\n    \"cart\": {\n      \"logs\": {\n        \"logs_cart_100\": {\n          \"method\": \"over\",\n          \"items\": {\n            \"111\": {\n              \"firstName\": \"Ram\",\n              \"lastName\": \"K\",\n              \"price\": {\n                \"amount\": 100.0,\n                \"baseAmount\": 100.0\n              }\n            },\n            \"222\": {\n              \"firstName\": \"Velvan\",\n              \"lastName\": \"S\",\n              \"price\": {\n                \"amount\": 200.0,\n                \"baseAmount\": 200.0\n              }\n            },\n            \"333\": {\n              \"firstName\": \"Dinesh\",\n              \"lastName\": \"M\",\n              \"price\": {\n                \"amount\": 300.0,\n                \"baseAmount\": 300.0\n              }\n            }\n          }\n        }\n      },\n      \"promotions\": [\n        {\n          \"promotionName\": \"Dummy-1\"\n        },\n        {\n          \"promotionName\": \"Dummy-2\"\n        },\n        {\n          \"promotionName\": \"Dummy-3\"\n        }\n      ]\n    }\n  }\n}";
        ObjectMapper mapper = new ObjectMapper();
        JsonNode actualObj = mapper.readValue(response, JsonNode.class);

        List<PriceDetail> priceList = new ArrayList<>();
        // 按层级定位到商品集合节点
        JsonNode itemsNode = actualObj.get("content")
                .get("cart")
                .get("logs")
                .get("logs_cart_100")
                .get("items");

        // 遍历所有商品节点提取price信息
        Iterator<Map.Entry<String, JsonNode>> itemsIterator = itemsNode.fields();
        while (itemsIterator.hasNext()) {
            Map.Entry<String, JsonNode> entry = itemsIterator.next();
            String itemId = entry.getKey();
            JsonNode priceNode = entry.getValue().get("price");
            Double amount = priceNode.get("amount").asDouble();
            Double baseAmount = priceNode.get("baseAmount").asDouble();
            priceList.add(new PriceDetail(itemId, amount, baseAmount));
        }

        // 验证输出结果
        for (PriceDetail detail : priceList) {
            System.out.printf("商品ID：%s，支付金额：%.2f，基准金额：%.2f%n",
                    detail.getItemId(), detail.getAmount(), detail.getBaseAmount());
        }
    }
}

场景2：未知JSON结构，全节点递归匹配提取 #

如果后续JSON结构会变动，可通过递归遍历所有节点匹配price字段提取，代码实现如下：

// 递归遍历节点方法
public static void traverseAllNode(JsonNode node, List<PriceDetail> priceList, String currentItemId) {
    if (node.isObject()) {
        Iterator<Map.Entry<String, JsonNode>> fields = node.fields();
        while (fields.hasNext()) {
            Map.Entry<String, JsonNode> field = fields.next();
            String fieldName = field.getKey();
            JsonNode fieldValue = field.getValue();
            if ("price".equals(fieldName)) {
                // 匹配到price字段直接提取
                Double amount = fieldValue.get("amount").asDouble();
                Double baseAmount = fieldValue.get("baseAmount").asDouble();
                priceList.add(new PriceDetail(currentItemId, amount, baseAmount));
            } else {
                // 记录当前商品ID供提取price时使用
                String newItemId = currentItemId;
                if (fieldName.matches("\\d+")) {
                    newItemId = fieldName;
                }
                traverseAllNode(fieldValue, priceList, newItemId);
            }
        }
    } else if (node.isArray()) {
        for (JsonNode arrayItem : node) {
            traverseAllNode(arrayItem, priceList, currentItemId);
        }
    }
}

// 调用方式
public static void main(String[] args) throws Exception {
    String response = "你的实际响应报文";
    ObjectMapper mapper = new ObjectMapper();
    JsonNode actualObj = mapper.readValue(response, JsonNode.class);
    List<PriceDetail> priceList = new ArrayList<>();
    traverseAllNode(actualObj, priceList, null);
    // 后续自行处理priceList即可
}

结果说明 #

两种方式最终都会提取到3条price明细，对应ID为111、222、333的三个商品的金额数据。

内容的提问来源于stack exchange，提问作者Krish