JSON Schema定义 +Networknt validator格式校验

一、介绍

JSON Schema是基于JSON的格式的规范，用于定义JSON数据的结构。

官网：https://ajv.js.org/json-schema.html

在线验证：https://www.jsonschemavalidator.net/

在json-schema官网上可以看到，java版本的validator库推荐了以下几种方案：

Snow 2019-09, draft-07, -06 Uses Maven for the project and Gson under the hood. (GNU Affero General Public License v3.0)

everit-org/json-schema draft-07, -06, -04 (Apache License 2.0)

Justify draft-07, -06, -04 (Apache License 2.0)

networknt/json-schema-validator draft-07, -06, -04 Support OpenAPI 3.0 with Jackson parser (Apache License 2.0)

常用的json-schema-validator库有：everit-org/json-schema和networknt/json-schema-validator ，在everit-org/json-schema的github介绍中可知，如果项目代码中使用jackson进行的json解析，推荐使用后者进行校验；如果使用的是org.json API 进行json解析，推荐使用前者校验。

everit：GitHub - everit-org/json-schema: JSON Schema validator for java, based on the org.json API

networknt： https://github.com/networknt/json-schema-validator

fge：https://github.com/java-json-tools/json-schema-validator

注意：fge/json-schema-validator也称作 java-json-tools/json-schema-validator

参考：https://blog.csdn.net/liuxiao723846/article/details/108578544

二、性能对比

在networknt github上有一个三者的性能对比，最快的是networknt。

fge: 7130ms

everit-org: 1168ms

networknt: 223ms

三、json Schema示例

示例1

{"type":"object","required":["client_side_conn_param","server_side_conn_param","bypass_duplicated_packet"],"properties":{"client_side_conn_param":{"$ref":"#/$defs/conn_params"},"server_side_conn_param":{"$ref":"#/$defs/conn_params"},"bypass_duplicated_packet":{"type":"integer","enum":[0,1]}},"$defs":{"conn_params":{"type":"object","required":["tcp_maxseg","nodelay","keep_alive","ttl","user_timeout"],"properties":{"tcp_maxseg":{"type":"object","properties":{"enable":{"type":"integer","enum":[0,1]},"maxseg":{"type":"integer"}},"if":{"properties":{"enable":{"const":1}}},"then":{"properties":{"maxseg":{"minimum":536,"maximum":1460}},"required":["maxseg"]}},"nodelay":{"type":"integer","enum":[0,1]},"keep_alive":{"type":"object","required":["enable"],"properties":{"enable":{"type":"integer","enum":[0,1]},"tcp_keepcnt":{"type":"integer"},"tcp_keepidle":{"type":"integer"},"tcp_keepintvl":{"type":"integer"}},"if":{"properties":{"enable":{"const":1}}},"then":{"properties":{"tcp_keepcnt":{"minimum":1,"maximum":222},"tcp_keepidle":{"minimum":30,"maximum":7200},"tcp_keepintvl":{"minimum":15,"maximum":75}},"required":["tcp_keepcnt","tcp_keepidle","tcp_keepintvl"]}},"ttl":{"type":"integer","minimum":1,"maximum":255},"user_timeout":{"type":"integer","minimum":200,"maximum":60000}}}}
}

示例2：array、maxItems、maxLength

{"type":"object","required":["method","rules"],"properties":{"method":{"type":"string","enum":["replace"]},"rules":{"type":"array","maxItems":16,"items":{"required":["search_in","find","replace_with"],"properties":{"regex_enable":{"type":"integer","enum":[0,1]},"search_in":{"type":"string"},"find":{"type":"string","minLength":1},"replace_with":{"type":"string","minLength":1}}}}}
}

示例3

{"type":"object","required":["method","rules"],"properties":{"method":{"type":"string","enum":["edit_element"]},"rules":{"type":"array","items":{"required":["anchor_element","target_element"],"properties":{"anchor_element":{"type":"object","required":["search_scope","contained_keyword"],"properties":{"search_scope":{"type":"string","enum":["whole_file","inside_element"]},"start_indicator":{"type":"string"},"contained_keyword":{"type":"string"}},"if":{"properties":{"search_scope":{"const":"inside_element"}}},"then":{"required":["start_indicator"]}},"target_element":{"type":"object","required":["target_distance_from_matching","element_treatment"],"properties":{"target_distance_from_matching":{"type":"integer"},"element_treatment":{"type":"string","enum":["mark","remove"]}}}}}}}
}

四、networknt验证

<dependency><groupId>com.networknt</groupId><artifactId>json-schema-validator</artifactId><version>1.0.76</version>
</dependency>

@Test
public void testNetworknt() {try {//可指定版本JsonSchemaFactory schemaFactory = JsonSchemaFactory.builder(com.networknt.schema.JsonSchemaFactory.getInstance(SpecVersion.VersionFlag.V7)).objectMapper(new ObjectMapper()).build();JsonSchema schema = schemaFactory.getSchema(JsonMapper.fromJsonString(replaceSchema, JsonNode.class));Set<ValidationMessage> validate = schema.validate(JsonMapper.fromJsonString(repData, JsonNode.class));Iterator<ValidationMessage> iterator = validate.iterator();while (iterator.hasNext()){ValidationMessage next = iterator.next();System.out.println(next.getMessage());}}catch(Exception e ){e.printStackTrace();}
}

五、遇到的问题

示例3在验证下述json时,使用V202012版本，anchor_element.search_scope的value不在枚举列表中未报异常，但V7版本可以。

Networknt要求使用的jaskson的版本在2.12.1以上，否则部分Json Schema属性无法使用，如maxItems、minLength。详见：https://github.com/networknt/json-schema-validator/issues/469

异常信息：

14:43:19.498 [main] DEBUG com.networknt.schema.PropertiesValidator - validate( {"name":"o"}, {"name":"o"}, $)
14:43:19.499 [main] WARN com.networknt.schema.JsonMetaSchema - Could not load validator minLength
com.networknt.schema.JsonSchemaException: java.lang.NoSuchMethodError: com.fasterxml.jackson.databind.JsonNode.canConvertToExactIntegral()Zat com.networknt.schema.JsonMetaSchema.newValidator(JsonMetaSchema.java:293)at com.networknt.schema.ValidationContext.newValidator(ValidationContext.java:57)at com.networknt.schema.JsonSchema.read(JsonSchema.java:236)at com.networknt.schema.JsonSchema.getValidators(JsonSchema.java:524)at com.networknt.schema.JsonSchema.validate(JsonSchema.java:315)at com.networknt.schema.PropertiesValidator.validate(PropertiesValidator.java:69)at com.networknt.schema.JsonSchema.validate(JsonSchema.java:316)at com.networknt.schema.JsonSchema.validate(JsonSchema.java:299)at cn.nis.ntc.JsonValidate.testNetworknt(JsonValidate.java:92)at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)at java.lang.reflect.Method.invoke(Method.java:498)at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)at org.junit.runners.ParentRunner.run(ParentRunner.java:363)at org.junit.runner.JUnitCore.run(JUnitCore.java:137)at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:220)at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:53)
Caused by: java.lang.NoSuchMethodError: com.fasterxml.jackson.databind.JsonNode.canConvertToExactIntegral()Z