写一个支持多层级JSON字段差异比对，同事可以排除指定字段的java程序

以下是一个支持多层级JSON字段差异比对，同时可以排除指定字段的Java程序示例：

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.*;
import com.fasterxml.jackson.databind.node.ObjectNode;
import java.util.*;

public class JsonDiff {

    public static Set<String> ignoreSet = new HashSet<>(); //要忽略的字段

    /**
     * 比较两个JSON字符串的差异
     * @param json1 JSON字符串1
     * @param json2 JSON字符串2
     * @return 返回差异结果的JSON字符串
     * @throws Exception
     */
    public static String diff(String json1, String json2) throws Exception {
        ObjectMapper mapper = new ObjectMapper();
        JsonNode node1 = mapper.readTree(json1);
        JsonNode node2 = mapper.readTree(json2);
        return diff(node1, node2).toString();
    }

    /**
     * 比较两个JsonNode的差异
     * @param node1 JsonNode1
     * @param node2 JsonNode2
     * @return 返回差异结果的JsonNode
     */
    public static JsonNode diff(JsonNode node1, JsonNode node2) {
        if (!node1.getNodeType().equals(node2.getNodeType())) {
            return node2;
        }

        if (node1.isValueNode()) { //值节点
            if (node1.equals(node2)) {
                return null;
            } else {
                return node2;
            }
        }

        if (node1.isArray()) { //数组
            ArrayNode arrayNode1 = (ArrayNode) node1;
            ArrayNode arrayNode2 = (ArrayNode) node2;
            if (arrayNode1.size() != arrayNode2.size()) {
                return arrayNode2;
            }

            JsonNode diff = null;
            for (int i = 0; i < arrayNode1.size(); i++) {
                JsonNode temp = diff(arrayNode1.get(i), arrayNode2.get(i));
                if (temp != null && !temp.isNull()) {
                    if (diff == null) {
                        diff = arrayNode2.arrayNode();
                    }
                    ((ArrayNode) diff).add(temp);
                }
            }
            return diff;
        }

        ObjectNode objectNode1 = (ObjectNode) node1;
        ObjectNode objectNode2 = (ObjectNode) node2;

        // 比较差异
        ObjectNode diff = objectNode2.objectNode();
        Iterator<String> fieldNames = objectNode1.fieldNames();
        while (fieldNames.hasNext()) {
            String fieldName = fieldNames.next();
            if (ignoreSet.contains(fieldName)) {
                continue;
            }
            if (objectNode2.has(fieldName)) {
                JsonNode diffNode = diff(objectNode1.get(fieldName), objectNode2.get(fieldName));
                if (diffNode != null && !diffNode.isNull()) {
                    diff.set(fieldName, diffNode);
                }
            } else {
                diff.set(fieldName, objectNode1.get(fieldName));
            }
        }
        // 添加新增字段
        fieldNames = objectNode2.fieldNames();
        while (fieldNames.hasNext()) {
            String fieldName = fieldNames.next();
            if (ignoreSet.contains(fieldName)) {
                continue;
            }
            if (!objectNode1.has(fieldName)) {
                diff.set(fieldName, objectNode2.get(fieldName));
            }
        }

        if (diff.size() == 0) {
            return null;
        }

        return diff;
    }

    public static void main(String[] args) throws Exception {
        String json1 = "{\"name\":\"tom\",\"age\":10,\"address\":{\"city\":\"beijing\",\"district\":\"haidian\"},\"hobbies\":[\"reading\",\"swimming\"]}";
        String json2 = "{\"name\":\"jerry\",\"age\":11,\"address\":{\"city\":\"beijing\",\"district\":\"chaoyang\"},\"hobbies\":[\"reading\",\"playing football\"]}";

        ignoreSet.add("name"); //排除name字段的比较
        String diff = JsonDiff.diff(json1, json2);
        System.out.println("差异结果：" + diff);
    }
}

该程序使用了Jackson库来解析和比较JSON字符串和JsonNode，支持比较值节点、数组和对象节点的差异，并可以排除指定的字段进行比较。最终返回的是差异结果的JsonNode。在此基础上，可以将JsonNode转成字符串输出。