字段名"；“零件”；在JSON中，会导致反序列化失败

在下面的代码中，由于

com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize instance of `java.util.ArrayList<de.richtercloud.jackson.deserialize.list.of.objects.DeserializationTest$D>` out of FIELD_NAME token
 at [Source: (String)"{
            "a": [
                {
                    "c": {
                        "Parts": []
                    }
                }
            ]
        }"; line: 5, column: 25] (through reference chain: de.richtercloud.jackson.deserialize.list.of.objects.DeserializationTest$A["a"]->java.util.ArrayList[0]->de.richtercloud.jackson.deserialize.list.of.objects.DeserializationTest$B["c"])

    at com.fasterxml.jackson.databind.exc.MismatchedInputException.from(MismatchedInputException.java:59)
    at com.fasterxml.jackson.databind.DeserializationContext.reportInputMismatch(DeserializationContext.java:1442)
    at com.fasterxml.jackson.databind.DeserializationContext.handleUnexpectedToken(DeserializationContext.java:1216)
    at com.fasterxml.jackson.databind.DeserializationContext.handleUnexpectedToken(DeserializationContext.java:1168)
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.handleNonArray(CollectionDeserializer.java:332)
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:265)
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:245)
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:27)
    at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.deserializeFromObjectUsingNonDefault(BeanDeserializerBase.java:1284)
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:326)
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:159)
    at com.fasterxml.jackson.databind.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:530)
    at com.fasterxml.jackson.databind.deser.BeanDeserializer._deserializeWithErrorWrapping(BeanDeserializer.java:528)
    at com.fasterxml.jackson.databind.deser.BeanDeserializer._deserializeUsingPropertyBased(BeanDeserializer.java:417)
    at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.deserializeFromObjectUsingNonDefault(BeanDeserializerBase.java:1287)
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:326)
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:159)
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:286)
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:245)
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:27)
    at com.fasterxml.jackson.databind.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:530)
    at com.fasterxml.jackson.databind.deser.BeanDeserializer._deserializeWithErrorWrapping(BeanDeserializer.java:528)
    at com.fasterxml.jackson.databind.deser.BeanDeserializer._deserializeUsingPropertyBased(BeanDeserializer.java:417)
    at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.deserializeFromObjectUsingNonDefault(BeanDeserializerBase.java:1287)
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:326)
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:159)
    at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4202)
    at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3205)
    at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3173)
    at de.richtercloud.jackson.deserialize.list.of.objects.DeserializationTest.testDeserialization(DeserializationTest.kt:22)
[omitted JUnit stacktrace]

我希望无论我选择哪个名称，这个测试都能工作，因为字段名是数据，不应该对反序列化算法的行为有任何影响

我尝试了

parts

、

a

和许多其他名称，并在

jackson-databind

源代码中在线搜索“parts”是关键字的提示

将

.configure（反序列化功能.ACCEPT_SINGLE_VALUE_AS_ARRAY，true）

添加到

ObjectMapper

初始化会导致异常消息更改为

com.fasterxml.jackson.module.kotlin.MissingKotlinParameterException:JSON属性e的[simple type，class de.richtercloud.jackson.deserialize.list.of.objects.DeserializationTest$D]值失败，因为creator参数e的值不可为NULL（因此为NULL），该参数是不可为NULL的类型

我正在使用以下版本：

<properties>
    <kotlin.version>1.3.61</kotlin.version>
    <junit5.version>5.5.2</junit5.version>
    <jackson.version>2.10.1</jackson.version>
</properties>

<dependencies>
    <dependency>
        <groupId>org.jetbrains.kotlin</groupId>
        <artifactId>kotlin-stdlib</artifactId>
        <version>${kotlin.version}</version>
    </dependency>
    <dependency>
        <groupId>org.jetbrains.kotlin</groupId>
        <artifactId>kotlin-reflect</artifactId>
        <version>${kotlin.version}</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
        <version>${jackson.version}</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.module</groupId>
        <artifactId>jackson-module-kotlin</artifactId>
        <version>${jackson.version}</version>
    </dependency>

    <!-- test dependencies -->
    <dependency>
        <groupId>org.junit.jupiter</groupId>
        <artifactId>junit-jupiter</artifactId>
        <version>${junit5.version}</version>
        <scope>test</scope>
    </dependency>
</dependencies>

1.3.61
5.5.2
2.10.1
org.jetbrains.kotlin
科特林标准实验室
${kotlin.version}
org.jetbrains.kotlin
科特林反射
${kotlin.version}
com.fasterxml.jackson.core
杰克逊数据绑定
${jackson.version}
com.fasterxml.jackson.module
杰克逊模块科特林
${jackson.version}
org.junit.jupiter
朱尼特朱庇特
${junit5.version}
测试

我可以通过指定

data class C(@JsonProperty("Parts") val parts: List<D>)

数据类C（@JsonProperty（“零件”）val零件：列表）

然而，我想了解这个问题/行为。

这是杰克逊的一个“特点”：

建议的解决方案是使用

@JsonProperty

，就像您已经做的那样

只有

snake\u case

键也可以正常工作，不过：

internal class DeserializationTest {

    @Test
    fun testDeserialization() {
        val serialized = """{
            "a": [
                {
                    "c": {
                        "parts": []
                    }
                }
            ]
        }"""
        val deserialized = createObjectMapper().readValue(serialized, A::class.java)
        assertNotNull(deserialized)
    }

    fun createObjectMapper() = ObjectMapper().registerModule(KotlinModule())

    data class A(val a: List<B>)

    data class B(val c: C)

    data class C(val parts: List<D>)

    data class D(var e: String)
}

内部类反序列化测试{
@试验
有趣的testDeserialization（）{
val序列化为“”{
“a”：[
{
“c”：{
“部分”：[]
}
}
]
}"""
val反序列化=createObjectMapper（）.readValue（序列化，A:：class.java）
assertNotNull（反序列化）
}
fun createObjectMapper（）=ObjectMapper（）.registerModule（KotlinModule（））
数据类别A（val A:列表）
数据类别B（val c:c）
数据类别C（val零件：列表）
数据类D（变量e:字符串）
}

internal class DeserializationTest {

    @Test
    fun testDeserialization() {
        val serialized = """{
            "a": [
                {
                    "c": {
                        "parts": []
                    }
                }
            ]
        }"""
        val deserialized = createObjectMapper().readValue(serialized, A::class.java)
        assertNotNull(deserialized)
    }

    fun createObjectMapper() = ObjectMapper().registerModule(KotlinModule())

    data class A(val a: List<B>)

    data class B(val c: C)

    data class C(val parts: List<D>)

    data class D(var e: String)
}