如何使用 jackson 反序列化为 Kotlin 集合 [英] How to use jackson to deserialize to Kotlin collections

问题描述

我想要的示例代码:

data class D(val a: String, val b: Int)
val jsonStr = """[{"a": "value1", "b": 1}, {"a": "value2", "b":"2}]"""
// what I need
val listOfD: List<D> = jacksonObjectMapper().whatMethodAndParameter?

推荐答案

With Jackson Kotlin Module 当前版本，如果您导入完整的模块包或特定的扩展功能，您将拥有所有可用的扩展方法.如:

With Jackson Kotlin Module current versions, if you import the full module package or the specific extension function you'll have all extension methods available. Such as:

import com.fasterxml.jackson.module.kotlin.*  
val JSON = jacksonObjectMapper()  // keep around and re-use
val myList: List<String> = JSON.readValue("""["a","b","c"]""")

因此 Kotlin 的 Jackson Module 将推断出正确的类型，您不需要 TypeReference 实例.

Therefore the Jackson Module for Kotlin will infer the the correct type and you do not need a TypeReference instance.

所以你的情况(稍微重命名并修复了数据类和 JSON):

so your case (slightly renamed and fixed the data class, and JSON):

import com.fasterxml.jackson.module.kotlin.readValue

data class MyData(val a: String, val b: Int)
val JSON = jacksonObjectMapper()  

val jsonStr = """[{"a": "value1", "b": 1}, {"a": "value2", "b": 2}]"""
val myList: List<MyData> = JSON.readValue(jsonStr)

您也可以使用表格:

val myList = JSON.readValue<List<MyData>>(jsonStr)

不导入就会报错，因为找不到扩展函数.

Without the import you will have an error because the extension function is not found.

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