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对比两个json串的diff，支持map的深度递归

news 2025/9/16 1:13:08

背景

项目重构，对老接口进行技术改造。动代码后，难免会有些bug，我们需要对比改造前后接口的返回，来判断逻辑是否有问题，这就涉及两个json的对比。

常规的diff文本工具是按行对比，无法处理复杂的map。本文通过gson来解析json，进而递归寻找diff。

依赖

<dependency><groupId>com.google.code.gson</groupId><artifactId>gson</artifactId><version>2.8.5</version>
</dependency>

代码


import com.google.common.collect.Sets;
import com.google.gson.Gson;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.tencent.trpc.core.utils.JsonUtils;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.HashSet;
import java.util.Objects;
import java.util.Set;
import java.util.stream.Collectors;public class Test {public static Set<String> diffKeySet = new HashSet<>();// 自定义需要忽略的字段public static Set<String> ignores = Sets.newHashSet("code","message");public static void main(String[] args) throws Exception {String formalStr = loadText("../formalStr.txt");String devStr = loadText("../devStr.txt");JsonObject formal = formal(formalStr);JsonObject dev = dev(devStr);findDiff("", formal, dev);filter();System.out.println(JsonUtils.toJson(diffKeySet));System.out.println(JsonUtils.toJson(diffKeySet.stream().map(s -> s.replaceAll("[\\d]", "")).collect(Collectors.toSet())));}private static void filter() {diffKeySet.removeIf(key -> ignores.stream().anyMatch(key::contains));}private static String loadText(String filePath) throws Exception {FileInputStream inputStream = null;BufferedReader bufferedReader = null;StringBuilder builder = new StringBuilder();try {String line;inputStream = new FileInputStream(filePath);bufferedReader = new BufferedReader(new InputStreamReader(inputStream));while ((line = bufferedReader.readLine()) != null) {builder.append(line.trim());}return builder.toString();} finally {close(inputStream, bufferedReader);}}public static void close(FileInputStream inputStream, BufferedReader bufferedReader) {try {if (inputStream != null) {inputStream.close();}if (bufferedReader != null) {bufferedReader.close();}} catch (IOException e) {e.printStackTrace();}}private static void findDiff(String prefix, JsonObject formal, JsonObject dev) {Set<String> formalKeySet = formal.keySet();formalKeySet.forEach(key -> {JsonElement formalElement = formal.get(key);JsonElement devElement = dev.get(key);findElementDiff(prefix, key, formalElement, devElement);});}public static void findElementDiff(String prefix, String key, JsonElement formalElement, JsonElement devElement) {String diffKeyPath = prefix + ":" + key;if (isNull(formalElement, devElement, diffKeyPath)) {return;}if (formalElement.isJsonObject()) {// 处理mapcheckObject(formalElement, devElement, diffKeyPath);return;}if (formalElement.isJsonArray()) {// 处理集合checkCollection(prefix, key, formalElement, devElement, diffKeyPath);return;}//if (formalElement.isJsonPrimitive()) {// 基本类型if (!formalElement.getAsString().equals(devElement.getAsString())) {addDiff(diffKeyPath);}//}}private static boolean isNull(JsonElement formalElement, JsonElement devElement, String diffKeyPath) {if (Objects.isNull(formalElement) || formalElement.isJsonNull()) {if (Objects.isNull(devElement) || devElement.isJsonNull()) {return true;}addDiff(diffKeyPath);return true;}if (Objects.isNull(devElement) || devElement.isJsonNull()) {addDiff(diffKeyPath);return true;}return false;}private static void checkObject(JsonElement formalElement, JsonElement devElement, String diffKeyPath) {if (!devElement.isJsonObject()) {addDiff(diffKeyPath);return;}JsonObject formalObject = formalElement.getAsJsonObject();JsonObject devObject = devElement.getAsJsonObject();findDiff(diffKeyPath, formalObject, devObject);}private static void checkCollection(String prefix, String key, JsonElement formalElement, JsonElement devElement,String diffKeyPath) {if (!devElement.isJsonArray()) {addDiff(diffKeyPath);return;}JsonArray formalArr = formalElement.getAsJsonArray();JsonArray devArr = devElement.getAsJsonArray();int size = formalArr.size();if (size != devArr.size()) {addDiff(diffKeyPath);return;}for (int i = 0; i < size; i++) {JsonElement formalArrElement = formalArr.get(i);JsonElement devArrElement = devArr.get(i);findElementDiff(prefix, String.format("%s[%d]", key, i), formalArrElement, devArrElement);}}public static void addDiff(String path) {diffKeySet.add(path);}public static JsonObject dev(String devJson) {return new Gson().fromJson(devJson, JsonObject.class);}public static JsonObject formal(String formalJson) {return new Gson().fromJson(formalJson, JsonObject.class);}