根据字段的存在和另一个字段的值反序列化JSON

gk7wooem  于 2023-05-08  发布在  其他
关注(0)|答案(1)|浏览(177)

如何将JSON有效负载反序列化为基于类型层次结构的特定具体类型,该类型层次结构包括四个端具体类型,每个端具体类型有两个抽象子类型?
子类型可以通过检查JobCallback是否存在“.job”或NotificationCallback是否存在“.notify”来确定。
一旦知道子类型,我们就可以通过查看字段“object.type”的值来确定具体类型。
层次结构包括根抽象类Callback,具有两个抽象子类JobCallback和NotificationCallback,以及四个具体类:DomainJobCallback、TransferJobCallback、DomainNotificationCallback和TransferNotificationCallback。

+-------------------------+                                                                                  
                                                                                 |  Callback (abstract)    |                                                                                  
                                                                                 +-------------------------+                                                                                  
                                                                                              /-\                                                                                             
                                                                                            /-   -\                                                                                           
                                                                                         /--       --\                                                                                        
                                                                                       /-             -\                                                                                      
                                                                                    /--                 --\                                                                                   
                                                                                  /-                       -\     <ROOT>.notify != null                                                       
                                                         <ROOT>.job != null    /--                           --\                                                                              
                                                                            /--                                 -\                                                                            
                                                                          /-                                      --\                                                                         
                                                                       /--                                           -\                                                                       
                                                                     /-                                                --\                                                                    
                                                                  /--                                                     -\                                                                  
                                                                /-                                                          --                                                                
                                                +------------------------+                                 +-----------------------------------+                                              
                                                | JobCallback (abstract) |                                 | NotificationCallback (abstract)   |                                              
                                                +------------------------+                                 +-----------------------------------+                                              
                                                           /-                                                                   /  --                                                         
                                                         /-  \-                                 <ROOT>.object.type == "Domain"/-     \-                                                       
                                                       /-      \                                                             /         \--                                                    
                                                     /-         \-                                                         /-             \--                                                 
                 <ROOT>.object.type == "Domain"    /-             \ <ROOT>.object.type == "Transfer"                     /-                  \-   <ROOT>.object.type = "Transfer"             
                                                 /-                \-                                                   /                      \--                                            
                                               /-                    \                                                /-                          \--                                         
                                             /-                       \-                                             /                               \-                                       
                                           /-                           \                                          /-                                  \--                                    
                                         /-                              \-                                       -                                       \-                                  
                 +-------------------------------+        +--------------------------------+   +--------------------------------------+        +----------------------------------------+     
                 |DomainJobCallback (concrete)   |        | TransferJobCallback (concrete) |   |DomainNotificationCallback (concrete) |        | TransferNotificationCallback (concrete)|     
                 +-------------------------------+        +--------------------------------+   +--------------------------------------+        +----------------------------------------+

JSON示例:

  • 域名JobCallback *
{
  "job": "example-job",
  "object": {
    "type": "Domain"
  }
}
  • 调动工作回调 *
{
  "job": "example-job",
  "object": {
    "type": "Transfer"
  }
}
  • 域名通知回调 *
{
  "notify": "example-notify",
  "object": {
    "type": "Domain"
  }
}
  • 转账通知回拨 *
{
  "notify": "example-notify",
  "object": {
    "type": "Transfer"
  }
}

**方式一:**我最初想到的是回调使用com.fasterxml.Jackson.annotation.JsonTypeInfo.Id#DEDUCTION,JobCallback和NotificationCallback使用com.fasterxml.jackson.annotation.JsonTypeInfo.Id#NAME。然而,我知道覆盖@JsonTypeInfo是不可能的(https://github.com/FasterXML/jackson-databind/issues/3358)。
**方法2:**然后我写了一个自定义的反序列化器,它检查字段.job和.notify的存在,并相应地将工作委托给每个子类型的解析器。我认为从这里开始重用默认解析应该很容易,因为现在我已经确定了子类型,并且我可以查看.object.type的值以获得具体类型,为此我将@JsonTypeInfo和@JsonSubTypes添加到子类型类(JobCallback和NotificationCallback),并返回mapper.treeToValue(node,Callback.JobCallback.class); and mapper.treeToValue(node,Callback.NotificationCallback.class);从parseJobCallback和parseNotificationCallback。这种方法可以被注解掉。

我得到了以下例外:

com.fasterxml.jackson.databind.exc.InvalidTypeIdException: Could not resolve subtype of [simple type, class com.example.abc.ex.dm.sm.cf.xyz.schema.Callback$JobCallback]: missing type id property 'object.type'
 at [Source: UNKNOWN; line: -1, column: -1]
    at com.fasterxml.jackson.databind.exc.InvalidTypeIdException.from(InvalidTypeIdException.java:43)
    at com.fasterxml.jackson.databind.DeserializationContext.missingTypeIdException(DeserializationContext.java:1943)
    at com.fasterxml.jackson.databind.DeserializationContext.handleMissingTypeId(DeserializationContext.java:1456)
    at com.fasterxml.jackson.databind.jsontype.impl.TypeDeserializerBase._handleMissingTypeId(TypeDeserializerBase.java:307)
    at com.fasterxml.jackson.databind.jsontype.impl.AsPropertyTypeDeserializer._deserializeTypedUsingDefaultImpl(AsPropertyTypeDeserializer.java:180)
    at com.fasterxml.jackson.databind.jsontype.impl.AsPropertyTypeDeserializer.deserializeTypedFromObject(AsPropertyTypeDeserializer.java:115)
    at com.fasterxml.jackson.databind.jsontype.impl.AsPropertyTypeDeserializer.deserializeTypedFromAny(AsPropertyTypeDeserializer.java:208)
    at com.fasterxml.jackson.databind.JsonDeserializer.deserializeWithType(JsonDeserializer.java:152)
    at com.fasterxml.jackson.databind.deser.impl.TypeWrappedDeserializer.deserialize(TypeWrappedDeserializer.java:74)
    at com.fasterxml.jackson.databind.deser.DefaultDeserializationContext.readRootValue(DefaultDeserializationContext.java:322)
    at com.fasterxml.jackson.databind.ObjectMapper._readValue(ObjectMapper.java:4569)
    at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2798)
    at com.fasterxml.jackson.databind.ObjectMapper.treeToValue(ObjectMapper.java:3261)
    at com.example.abc.ex.dm.sm.cf.xyz.schema.CallbackDeserializer.parseJobCallback(CallbackDeserializer.java:36)
    at com.example.abc.ex.dm.sm.cf.xyz.schema.CallbackDeserializer.deserialize(CallbackDeserializer.java:23)
    at com.example.abc.ex.dm.sm.cf.xyz.schema.CallbackDeserializer.deserialize(CallbackDeserializer.java:10)
    at com.fasterxml.jackson.databind.deser.DefaultDeserializationContext.readRootValue(DefaultDeserializationContext.java:322)
    at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4593)
    at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3548)
    at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3516)
    at com.example.abc.ex.dm.sm.cf.xyz.MyJsonParsingTest.name(MyJsonParsingTest.java:87)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:688)
    at org.junit.jupiter.engine.execution.MethodInvocation.proceed(MethodInvocation.java:60)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain$ValidatingInvocation.proceed(InvocationInterceptorChain.java:131)
    at org.junit.jupiter.engine.extension.TimeoutExtension.intercept(TimeoutExtension.java:149)
    at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestableMethod(TimeoutExtension.java:140)
    at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestMethod(TimeoutExtension.java:84)
    at org.junit.jupiter.engine.execution.ExecutableInvoker$ReflectiveInterceptorCall.lambda$ofVoidMethod$0(ExecutableInvoker.java:115)
    at org.junit.jupiter.engine.execution.ExecutableInvoker.lambda$invoke$0(ExecutableInvoker.java:105)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain$InterceptedInvocation.proceed(InvocationInterceptorChain.java:106)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain.proceed(InvocationInterceptorChain.java:64)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain.chainAndInvoke(InvocationInterceptorChain.java:45)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain.invoke(InvocationInterceptorChain.java:37)
    at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:104)
    at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:98)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$invokeTestMethod$6(TestMethodTestDescriptor.java:210)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeTestMethod(TestMethodTestDescriptor.java:206)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:131)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:65)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:139)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$7(NodeTestTask.java:129)
    at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:127)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:126)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:84)
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1541)
    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:143)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$7(NodeTestTask.java:129)
    at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:127)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:126)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:84)
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1541)
    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:143)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$7(NodeTestTask.java:129)
    at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:127)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:126)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:84)
    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:32)
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57)
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:51)
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:108)
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:88)
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.lambda$execute$0(EngineExecutionOrchestrator.java:54)
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.withInterceptedStreams(EngineExecutionOrchestrator.java:67)
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:52)
    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:96)
    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:75)
    at com.intellij.junit5.JUnit5IdeaTestRunner.startRunnerWithArgs(JUnit5IdeaTestRunner.java:57)
    at com.intellij.rt.junit.IdeaTestRunner$Repeater$1.execute(IdeaTestRunner.java:38)
    at com.intellij.rt.execution.junit.TestsRepeater.repeat(TestsRepeater.java:11)
    at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:35)
    at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:232)
    at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:55)

**方式三:**知道子类型后,解析.object.type的值。

我进一步进行了解析,甚至在知道子类型后提取出具体类型的值。但是,这导致了StackOverflowError。我假设这是进入一个无限循环,因为我调用mapper.treeToValue(node,Callback.JobCallback.DomainJobCallback.class),并且也使用了相同的反序列化器。我知道如果我解析每个字段,然后构造具体的对象,就可以解决这个问题。但我不想手动解析到那个深度。
我也不确定我是否应该像现在这样在CallbackDeserializer中初始化一个对象Map器。
下面是复制此代码的代码:

package com.example.r.e.d.s.c.q;

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
import com.fasterxml.jackson.databind.exc.InvalidDefinitionException;
import org.junit.jupiter.api.Test;

import java.io.IOException;

class MyJsonParsingTest {

    private final ObjectMapper objectMapper = new ObjectMapper();

    @Test
    void test1() throws JsonProcessingException {

        String jsonPayload = "{\n" +
                "  \"job\": \"example-job\",\n" +
                "  \"object\": {\n" +
                "    \"type\": \"Domain\"\n" +
                "  }\n" +
                "}\n";

        Callback callback = objectMapper.readValue(jsonPayload, Callback.class);

        System.out.println("callback = " + callback);
    }

    public static class CallbackDeserializer extends JsonDeserializer<Callback> {

        private final ObjectMapper mapper = new ObjectMapper();

        @Override
        public Callback deserialize(final JsonParser jsonParser,
                                    final DeserializationContext deserializationContext) throws IOException {

            final JsonNode node = jsonParser.getCodec().readTree(jsonParser);

            final JsonNode jobCallbackNode = node.get("job");
            final JsonNode notificationCallbackNode = node.get("notify");

            if (jobCallbackNode != null) {
                return parseJobCallback(node, jsonParser);
            }
            else if (notificationCallbackNode != null) {
                return parseNotificationCallback(node, jsonParser);
            }
            else {
                throw InvalidDefinitionException.from(jsonParser, "Invalid callback type", (JavaType) null);
            }
        }

        private Callback parseJobCallback(final JsonNode node,
                                          final JsonParser jsonParser) throws IOException {

//                    return mapper.treeToValue(node, Callback.JobCallback.class);

            final String type = node.get("object").get("type").asText();

            if (type.equals("Domain")) {
                return mapper.treeToValue(node, Callback.JobCallback.DomainJobCallback.class);
            }
            else if (type.equals("Transfer")) {
                return mapper.treeToValue(node, Callback.JobCallback.TransferJobCallback.class);
            }
            throw InvalidDefinitionException.from(jsonParser, "Invalid job callback type", (JavaType) null);
        }

        private Callback parseNotificationCallback(final JsonNode node,
                                                   final JsonParser jsonParser) throws JsonProcessingException {

//                    return mapper.treeToValue(node, Callback.NotificationCallback.class);

            final String type = node.get("object").get("type").asText();
            if (type.equals("Domain")) {
                return mapper.treeToValue(node, Callback.NotificationCallback.DomainNotificationCallback.class);
            }
            else if (type.equals("Transfer")) {
                return mapper.treeToValue(node, Callback.NotificationCallback.TransferNotificationCallback.class);
            }
            throw InvalidDefinitionException.from(jsonParser, "Invalid job callback type", (JavaType) null);
        }
    }

    @JsonDeserialize(using = CallbackDeserializer.class)
    @JsonIgnoreProperties(ignoreUnknown = true)
    public abstract static class Callback {

        private Obj object;

        //        @JsonTypeInfo(use = JsonTypeInfo.Id.NAME, property = "object.type")
//        @JsonSubTypes({
//                @JsonSubTypes.Type(value = JobCallback.DomainJobCallback.class, name = "Domain"),
//                @JsonSubTypes.Type(value = JobCallback.TransferJobCallback.class, name = "Transfer"),
//        })
        @JsonIgnoreProperties(ignoreUnknown = true)
        public abstract static class JobCallback extends Callback {

            private String job;
        }

        @JsonIgnoreProperties(ignoreUnknown = true)
        public static class DomainJobCallback extends Callback.JobCallback {

        }

        @JsonIgnoreProperties(ignoreUnknown = true)
        public static class TransferJobCallback extends Callback.JobCallback {

        }

        //        @JsonTypeInfo(use = JsonTypeInfo.Id.NAME, property = "object.type")
//        @JsonSubTypes({
//                @JsonSubTypes.Type(value = NotificationCallback.DomainNotificationCallback.class, name = "Domain"),
//                @JsonSubTypes.Type(value = NotificationCallback.TransferNotificationCallback.class, name = "Contact")
//        })
        @JsonIgnoreProperties(ignoreUnknown = true)
        public static class NotificationCallback extends Callback {

            private String notify;

        }

        @JsonIgnoreProperties(ignoreUnknown = true)
        public static class DomainNotificationCallback extends NotificationCallback {

        }

        @JsonIgnoreProperties(ignoreUnknown = true)
        public static class TransferNotificationCallback extends NotificationCallback {

        }

        @JsonIgnoreProperties(ignoreUnknown = true)
        public static class Obj {

            private String type;

        }
    }
}
4bbkushb

4bbkushb1#

我认为您需要配置ObjectMapper使用基于字段的序列化(默认为基于bean的序列化,即。它查找getter/setter)。我还发现模块比注解更容易工作。例如:

final SimpleModule module = new SimpleModule();
    module.addDeserializer(Callback.class, new CallbackDeserializer());
    objectMapper.registerModule(module);
    objectMapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.NONE);
    objectMapper.setVisibility(PropertyAccessor.FIELD, JsonAutoDetect.Visibility.ANY);

    Callback callback = objectMapper.readValue(jsonPayload, Callback.class);

    // Check the results.
    System.out.println("callback = " + objectMapper.writeValueAsString(callback));

如果我运行它,我会得到以下结果,这表明它已经成功Map了JSON:

callback = {"object":{"type":"Domain"},"job":"example-job"}

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