Develop Reference

How use kotlinx.serialization decode generics list?

i have a json like this:
{"code":200,"msg":"111",data:[{"name":"va","list":[{"code":"11"}]},{"name":"va","list":[{"code":"11"}]}]}
my class like this:
#Serializable
class ServerResponse<T> {
#SerialName(value = "code")
var code = 0
#SerialName(value = "msg")
var msg: String? = null
#SerialName(value = "data")
var data: T? = null
private set
}
#Serializable
data class PluginInfo(
#SerialName(value = "name")
val name: String,
#SerialName(value = "list")
val list: MutableList<PluginConfig>
)
#Serializable
data class PluginConfig(
#SerialName(value = "code")
val code: String
)
when i use JSON.decodeFromString:
val response =
json.decodeFromString<ServerResponse<MutableList<PluginInfo>>>(pluginInfoJson)
this throw exception:
kotlinx.serialization.json.internal.JsonDecodingException: Unexpected JSON token at offset 271: Expected quotation mark '"', but had '1' instead at path: $.data[0].

How to convert a map to Json string in kotlin?

I have a mutableMap,
val invoiceAdditionalAttribute = mutableMapOf<String, Any?>()
invoiceAdditionalAttribute.put("clinetId",12345)
invoiceAdditionalAttribute.put("clientName", "digital")
invoiceAdditionalAttribute.put("payload", "xyz")
I want to convert it into json string
the output should be,
"{\"clinetId\"=\"12345\", \"clientName\"=\"digital\", \"payload\"=\"xyz\"}"
Currently, I am using Gson library,
val json = gson.toJson(invoiceAdditionalAttribute)
and the output is
{"clinetId":12345,"clientName":"digital","payload":"xyz"}

The right json formatting string is:
{"clinetId":12345,"clientName":"digital","payload":"xyz"}
So this is the right method to get it:
val json = gson.toJson(invoiceAdditionalAttribute)
If you want a string formatted like this:
{"clinetId"=12345, "clientName"="digital", "payload"="xyz"}
just replace : with =:
val json = gson.toJson(invoiceAdditionalAttribute).replace(":", "=")
But if you truly want to have a string with backslashes and clinetId value to be inside quotes:
val invoiceAdditionalAttribute = mutableMapOf<String, Any?>()
invoiceAdditionalAttribute["clinetId"] = 12345.toString()
invoiceAdditionalAttribute["clientName"] = "digital"
invoiceAdditionalAttribute["payload"] = "xyz"
val json = gson.toJson(invoiceAdditionalAttribute)
.replace(":", "=")
.replace("\"", "\\\"")
EDIT:
As pointed int he comments .replace(":", "=") can be fragile if some string values contain a ":" character.
To avoid it I would write a custom extension function on Map<String, Any?>:
fun Map<String, Any?>.toCustomJson(): String = buildString {
append("{")
var isFirst = true
this#toCustomJson.forEach {
it.value?.let { value ->
if (!isFirst) {
append(",")
}
isFirst = false
append("\\\"${it.key}\\\"=\\\"$value\\\"")
}
}
append("}")
}
// Using extension function
val customJson = invoiceAdditionalAttribute.toCustomJson()

Why is #JacksonXmlProperty ignoring parameters in Spring Boot with Kotlin?

So I'm trying to serialize/deserialize RSS feeds using Jackson XML in Kotlin. However, currently it's not doing either properly. When I instantiate the RSS object manually and print out the xml, it seems like it's ignoring the localName and namespace parameters in #JacksonXmlProperty. Here is my code:
#JacksonXmlRootElement(localName="rss")
class RSSFeed(
#JacksonXmlProperty(localName="channel")
var channel: Channel
) {
constructor() : this(Channel())
}
class Channel(
#JacksonXmlProperty(localName="title")
var title: String? = null,
#JacksonXmlCData
#JacksonXmlProperty(localName="description")
var description: String? = null,
#JacksonXmlProperty(localName="image")
var image: RSSImage? = null,
#JacksonXmlProperty(localName = "explicit", namespace="itunes")
var isExplicit: String? = "no",
#JacksonXmlProperty(localName = "pubDate")
var publishDate: String? = null,
#JacksonXmlProperty(localName = "type", namespace="itunes")
var episodeType: String? = null,
#JacksonXmlProperty(localName = "link", namespace="atom")
var atomLink: AtomLink? = null,
#JacksonXmlProperty(localName = "new-feed-url", namespace="itunes")
var newFeedUrl: String? = null
)
Then I just do:
println(XmlMapper().writeValueAsString(RSSFeed(Channel(title = "blah", description = "blah", image = RSSImage(url = "https://someurl.com", link = "somelink"), isExplicit = "yes", atomLink = AtomLink(href="blah.com"), newFeedUrl = "thisisthenewfeed"))))
However, when I print that out it ignores the namespace and localName properties and just uses the variable names. What am I doing wrong?
Xml output: <rss><channel><title>blah</title><description><![CDATA[blah]]></description><image><url>https://someurl.com</url><title/><link><![CDATA[somelink]]></link></image><publishDate/><episodeType/><atomLink href="blah.com"/><newFeedUrl>thisisthenewfeed</newFeedUrl></channel></rss>
edit: it also doesn't seem to be printing the isExplicit property for some reason, not sure what that's about.

Well I figured it out! It turns out this was a Kotlin issue. I just had to do this: val xmlMapper = XmlMapper().registerModule(KotlinModule())
...and make sure that this is in your dependencies (I use gradle):
implementation("com.fasterxml.jackson.module:jackson-module-kotlin")
Anyways I hope this helps someone in the future.

JAXB unmarshalling xml list element to single Kotlin object

I have following XML to create nested Kotlin objects but it is not mapping all TimeCycleData element
<TimeCycle>
<Last>
<Date>2001-06-13T01:00:00.000Z</Date>
<TimeCycleData>
<Hours type="F">123</Hours>
</TimeCycleData>
<TimeCycleData>
<Cycles>1234</Cycles>
</TimeCycleData>
<TimeCycleData>
<Land>1234</Land>
</TimeCycleData>
</Last>
</TimeCycle>
and want to map following Kotlin data classes
data class TimeCycle(
#field:XmlElement(name = "Last")
val last: Last? = null
)
data class Last(
#field:XmlElement(name = "Date")
#field:XmlJavaTypeAdapter(value = LocalDateTimeAdapter::class, type = LocalDateTime::class)
val date: LocalDateTime? = null,
#field:XmlElement(name = "TimeCycleData")
val timeCycleData: TimeCycleData? = null
)
data class TimeCycleData(
#field:XmlElement(name = "Hours")
val hours: DurationDetails? = null,
#field:XmlElement(name = "Cycles")
val cycles: Int? = null,
#field:XmlElement(name = "Land")
val land: Int? = null
)
data class DurationDetails(
#field:XmlValue
#field:XmlJavaTypeAdapter(value = DurationAdapter::class, type = Duration::class)
val value: Duration? = null,
#field:XmlAttribute(name = "type")
val type: String = ""
)
when I unmarshal the XML, only the first TimeCycleData with Hours is filled. How can I merge all TimeCycleData into one single object?
UPDATE: corrected submitted xml

I guess
#field:XmlElement(name = "TimeCycleData")
val timeCycleData: TimeCycleData? = null
should be declared in somehow this way
#field:XmlElement(name = "TimeCycleData")
#field:XmlElementWrapper(name = "TimeCycleInfo")
val timeCycleInfo: List<TimeCycleData>? = null
.

XML unmarshal to Object in Java/Kotlin

I want to change a xml string to a object but it seems like keeps throwing error to me and I'm not sure how to use those #XmlRootElement stuff
Just view/reply it as JAVA also can although written in kotlin
Here it's the XML string
<xml>
<return_code><![CDATA[SUCCESS]]></return_code>
<return_msg><![CDATA[OK]]></return_msg>
<appid><![CDATA[wx0b6dc231d20b379f1]]></appid>
<mch_id><![CDATA[1508319851]]></mch_id>
<nonce_str><![CDATA[mqy4nB6xGoyC1QPY]]></nonce_str>
<sign><![CDATA[2D9A3195E196F679D3916C5DC74754B4]]></sign>
<result_code><![CDATA[SUCCESS]]></result_code>
<prepay_id><![CDATA[wx2116190646297891sfae86747980208850875]]></prepay_id>
<trade_type><![CDATA[JSAPI]]></trade_type>
</xml>
Here it's my data class
#XmlRootElement
data class WxPayResult(
val return_code: String = "",
val return_msg: String = "",
//return_code as SUCCESS will only return the following params
val appid: String? = null,
val mch_id: String? = null,
val device_info: String? = null,
val nonce_str: String? = null,
val sign: String? = null,
val result_code: String? = null,
val err_code: String? = null,
val err_code_des: String? = null,
//return_code and result_code both as success will only return the following params
val trade_type: String? = null,
val prepay_id: Int? = null,
val code_url: String? = null
)
Here it's my code, "xmlreturn" is the xml string
val jaxbContext = JAXBContext.newInstance(WxPayResult::class.java)
val unmarshaller = jaxbContext.createUnmarshaller()
val reader = StringReader(xmlreturn)
val person = unmarshaller.unmarshal(reader)
Here it's the error
javax.xml.bind.UnmarshalException: unexpected element (uri:"", local:"xml"). Expected elements are <{}wxPayResult>
at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallingContext.handleEvent(UnmarshallingContext.java:741)
at com.sun.xml.bind.v2.runtime.unmarshaller.Loader.reportError(Loader.java:262)
at com.sun.xml.bind.v2.runtime.unmarshaller.Loader.reportError(Loader.java:257)
at com.sun.xml.bind.v2.runtime.unmarshaller.Loader.reportUnexpectedChildElement(Loader.java:124)
at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallingContext$DefaultRootLoader.childElement(UnmarshallingContext.java:1149)
at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallingContext._startElement(UnmarshallingContext.java:574)
I know probably i need to add something into the data class but i don know what to add. Thanks in advance.

Your root element's name differs from your xml root element, which also the message suggests. It expects wxPayResult, but you give it a xml.
Either deliver an XML with wxPayResult as root element or supply the name to XMLRootElement, e.g.
#XmlRootElement(name = "xml")