java - 使用自定义 jackson 序列化器替换Enum值

Question

我正在Kotlin中编写一个Spring Boot项目。我拥有的POJO /数据类之一

data class Employee(
        //... other properties
        val designation: Designation
)

enum class Designation {
    JUN, MID, SEN
}

默认情况下，此Employee对象序列化为{"designation" : "JUN"}。我想添加一个自定义序列化程序，以便该对象将像{"designation" : "Junior"}这样进行序列化。

我添加的序列化器，

@JsonComponent
class DesignationSerialization {
    class Serializer: JsonObjectSerializer<Designation>() {
        override fun serializeObject(designation: Designation, gen: JsonGenerator, provider: SerializerProvider) {
            gen.writeString(designation.pretty)
        }

        private val Designation.pretty: String
            get() = when(this) {
                Designation.JUN -> "Junior"
                Designation.MID -> "Mid-Level"
                Designation.SEN -> "Senior"
            }
    }
}

但是在运行此程序时，出现此错误，

JSON encoding error: Can not write a string, expecting field name (context: Object); nested exception is com.fasterxml.jackson.core.JsonGenerationException: Can not write a string, expecting field name (context: Object)

我也尝试过使用gen.writeStringField("designation", designation.pretty)，但是这样可以序列化对象

{
"designation": {"designation": "Mid-Level"}
}

Answer 1

您应该在枚举类中添加一个属性，并用@JsonValue标记https://www.baeldung.com/jackson-serialize-enums