基于Java对于PostgreSQL多层嵌套JSON 字段判重

场景：把复杂的 CommonCondition 条件树以 JSON 形式存入 PostgreSQL，并要求：

• 子条件顺序、

• valueList 重复值、

• 展示用字段（如别名）
  不影响“相同业务逻辑”的判定。
  本文给出一条 Java → PostgreSQL 的端到端可复制方案。

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1. 数据库层设计（PostgreSQL）

CREATE TABLE report_condition (id        bigserial PRIMARY KEY,condition jsonb        NOT NULL,signature char(64)     NOT NULL,   -- SHA-256 长度created_at timestamptz DEFAULT now()
);-- 查询时直接按 signature 去重
CREATE UNIQUE INDEX uk_signature ON report_condition(signature);

触发器可选：如果希望完全由 DB 计算签名，可用 plpython3u 调用 Python 归一化脚本；
下文演示 Java 端计算签名后写入，逻辑更清晰。

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2. Java 端核心实现

2.1 枚举：白名单字段规则

package com.example.condition;import java.util.List;/** 不同业务场景下保留的字段集合 */
public enum ConditionNormalizeRule {DEFAULT(List.of("table","field","fieldType","type","logicalOperator","operator","valueList","commonConditions")),REPORT (List.of("table","field","type","operator","valueList","commonConditions")), // 去掉 fieldTypeAUDIT  (List.of("table","field","fieldType","type","operator","valueList","commonConditions"));private final List<String> whiteList;ConditionNormalizeRule(List<String> whiteList) { this.whiteList = whiteList; }public List<String> getWhiteList() { return whiteList; }
}

2.2 工具类 ConditionHash

package com.example.condition;import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.*;
import org.apache.commons.codec.digest.DigestUtils;import java.util.*;
import java.util.stream.Collectors;public final class ConditionHash {/** 全局 ObjectMapper，线程安全 */private static final ObjectMapper MAPPER = new ObjectMapper().setSerializationInclusion(JsonInclude.Include.NON_NULL) // 忽略 null.configure(SerializationFeature.ORDER_MAP_ENTRIES_BY_KEYS, true); // 键排序/*** 计算业务等价哈希* @param root  待计算的 CommonCondition 树* @param rule  决定保留哪些字段的枚举* @return      SHA-256 十六进制字符串（64 位）*/public static String sha256(CommonCondition root, ConditionNormalizeRule rule) {try {JsonNode tree = normalize(MAPPER.valueToTree(root), rule);byte[] bytes  = MAPPER.writeValueAsBytes(tree);return DigestUtils.sha256Hex(bytes);} catch (Exception e) {throw new IllegalStateException("compute hash failed", e);}}/* ---------- 私有归一化逻辑 ---------- *//** 递归归一化：保留白名单字段 + 去重排序 */private static JsonNode normalize(JsonNode node, ConditionNormalizeRule rule) {if (node == null || !node.isObject()) return node;ObjectNode obj = MAPPER.createObjectNode();List<String> white = rule.getWhiteList();white.forEach(key -> {if (node.has(key)) {JsonNode val = node.get(key);switch (key) {case "valueList":obj.set(key, normalizeValueList(val));         // 去重+排序break;case "commonConditions":obj.set(key, normalizeChildren(val, rule));    // 递归+排序break;default:obj.set(key, val);                             // 直接保留}}});return obj;}/** valueList 去重+字典序排序 */private static JsonNode normalizeValueList(JsonNode listNode) {if (listNode == null || !listNode.isArray()) return MAPPER.createArrayNode();List<String> list = MAPPER.convertValue(listNode, new TypeReference<>() {});list = list.stream().distinct().sorted().collect(Collectors.toList());return MAPPER.valueToTree(list);}/** commonConditions 递归归一化后按字符串排序 */private static JsonNode normalizeChildren(JsonNode childrenNode, ConditionNormalizeRule rule) {if (childrenNode == null || !childrenNode.isArray()) return MAPPER.createArrayNode();List<CommonCondition> children = MAPPER.convertValue(childrenNode, new TypeReference<>() {});List<JsonNode> sorted = children.stream().map(c -> normalize(MAPPER.valueToTree(c), rule)).sorted(Comparator.comparing(JsonNode::toString)) // 稳定排序.collect(Collectors.toList());return MAPPER.valueToTree(sorted);}private ConditionHash() {}
}

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3. 使用示例

3.1 构造两个“业务等价”的对象

CommonCondition condA = CommonCondition.builder().type("logical").logicalOperator("AND").commonConditions(List.of(CommonCondition.builder().type("base").table("user").field("age").operator("GT").valueList(List.of("18", "18", "20"))  // 重复值.build(),CommonCondition.builder().type("base").table("user").field("status").operator("IN").valueList(List.of("ACTIVE", "LOCKED")).build())).build();/* 把子条件顺序颠倒，再加一个别名字段，但业务含义不变 */
CommonCondition condB = CommonCondition.builder().type("logical").logicalOperator("AND").tableNameAlias("u")            // 展示用，不参与哈希.commonConditions(List.of(CommonCondition.builder().type("base").table("user").field("status").operator("IN").valueList(List.of("LOCKED", "ACTIVE", "ACTIVE")) // 重复+乱序.build(),CommonCondition.builder().type("base").table("user").field("age").operator("GT").valueList(List.of("20", "18"))   // 乱序.build())).build();

3.2 计算哈希并判重

String sigA = ConditionHash.sha256(condA, ConditionNormalizeRule.DEFAULT);
String sigB = ConditionHash.sha256(condB, ConditionNormalizeRule.DEFAULT);System.out.println("sigA = " + sigA);
System.out.println("sigB = " + sigB);
System.out.println("same = " + sigA.equals(sigB));   // true

3.3 插入 PostgreSQL

String sql = """INSERT INTO report_condition(condition, signature)VALUES (?::jsonb, ?)ON CONFLICT (signature) DO NOTHING""";
try (PreparedStatement ps = conn.prepareStatement(sql)) {ps.setString(1, new ObjectMapper().writeValueAsString(condA));ps.setString(2, sigA);ps.executeUpdate();
}

ON CONFLICT (signature) DO NOTHING 利用唯一索引实现幂等写入，天然判重。

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4. 性能 & 扩展

子条件规模	耗时（MacBook M2）	建议
< 100	< 1 ms	无需优化
100~1 000	1~8 ms	缓存哈希
> 1 000	> 10 ms	并行流 + 缓存

缓存示例（Lombok）：

@Getter(lazy = true)
private final String hash = ConditionHash.sha256(this, ConditionNormalizeRule.DEFAULT);

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5. 小结

1. 数据库：JSONB + 唯一索引 signature，一行 SQL 完成判重。

2. Java：ConditionHash.sha256(root, rule) 统一出口，顺序、重复、别名全部抹平。

3. 枚举：新增业务场景只需再加一个 ConditionNormalizeRule 值，零侵入。