英文:
JSON decoding from stream in Kotlin
问题
抱歉，你的请求中包含代码部分，根据你的要求，我将提供代码部分的翻译：
我已经设置了一个服务器来通过本地主机端口发送消息。我试图解码服务器发送的序列化JSON消息并出现了以下错误。
错误解码消息：kotlinx.serialization.json.internal.JsonDecodingException: 偏移55处出现意外的JSON令牌：预期在解析后出现EOF，但实际是在路径$中出现了。
JSON输入：.....mber":13,"Timestamp":5769784} ......
Racer State消息的JSON格式如下：{“SensorId”:“值”,“RacerBibNumber”:“值”,“Timestamp”:“值”}，其中值是字段值的字符字符串表示。我还尝试将我的RacerStatus类更改为接受String而不是Int，但出现了类似的错误。我在这里是否漏掉了什么？错误中缺少的符号无法复制，所以我知道它不是UTF-8。
我还添加了以下代码：
val inputString = bytes.toString(Charsets.UTF_8)
println("Received input: $inputString")
这会得到以下结果：
Received input: ```{"SensorId":0,"RacerBibNumber":5254,"Timestamp":3000203} ```，末尾带有大量不相关的符号。
```@Serializable
data class RacerStatus(
var SensorId: Int,
var RacerBibNumber: Int,
var Timestamp: Int
) {
fun encode(): ByteArray {
return Json.encodeToString(serializer(), this).toByteArray()
}
companion object {
fun decode(bytes: ByteArray): RacerStatus {
print(bytes[0])
try {
val mstream = ByteArrayInputStream(bytes)
return Json.decodeFromStream<RacerStatus>(mstream)
} catch (e: SerializationException) {
println("Error decoding message: $e")
return RacerStatus(0, 0, 0)
}
// return Json.decodeFromString(serializer(), mstream.readBytes().toString())
}
}
}
希望这些翻译对你有帮助。如果你需要更多帮助，请随时提问。
英文:
I have a server set up to send messages over a local host port. I am trying to decode the serialized json messages sent by the server and get this error.
Error decoding message: kotlinx.serialization.json.internal.JsonDecodingException: Unexpected JSON token at offset 55: Expected EOF after parsing, but had instead at path: $
JSON input: .....mber":13,"Timestamp":5769784} .....
The Racer State messages are formatted in JSON as follows: { “SensorId”: “value”, “RacerBibNumber” : “value”, “Timestamp” : “value” }, where the value’s are character string representations of the field values. I have also tried changing my RacerStatus Class to take String instead of Int but to a similar error. Am I missing something here? The symbol that is missing in the error was not able to be copied over so I know it's not UTF-8.
I have also added
val inputString = bytes.toString(Charsets.UTF_8)
println("Received input: $inputString")
This gets
Received input: {"SensorId":0,"RacerBibNumber":5254,"Timestamp":3000203}
with a bunch of extraneous symbols at the end.
data class RacerStatus(
var SensorId: Int,
var RacerBibNumber: Int,
var Timestamp: Int
) {
fun encode(): ByteArray {
return Json.encodeToString(serializer(), this).toByteArray()
}
companion object {
fun decode(bytes: ByteArray): RacerStatus {
print(bytes[0])
try {
val mstream = ByteArrayInputStream(bytes)
return Json.decodeFromStream<RacerStatus>(mstream)
} catch (e: SerializationException) {
println("Error decoding message: $e")
return RacerStatus(0, 0, 0)
}
// return Json.decodeFromString(serializer(), mstream.readBytes().toString())
}
}
}
答案1
得分: 0
我找到了答案解决我的问题。我添加了一个正则表达式，以包括我知道我的 JSON 包含的 JSON 组件。
val str = bytes.toString(Charsets.UTF_8)
val re = Regex("[^A-Za-z0-9{}:,\"]")
return Json.decodeFromString<RacerStatus>(re.replace(str, ""))
我以为 Charsets.UTF_8 会去除杂字符，但实际上没有。是否有更直观的解决方案？另外，是否有一个可以覆盖 JSON 中所有可能值的正则表达式？
英文:
So I found an answer to my question. I added a regex to include just the json components I know my json contains.
val str = bytes.toString(Charsets.UTF_8)
val re = Regex("[^A-Za-z0-9{}:,\"\"]")
return Json.decodeFromString<RacerStatus>(re.replace(str,""))
I thought that Charsets.UTF_8 would remove the misc characters but it did not. Is there a more intiuative solution? Also is there a regex that would cover all possible values in json?
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