如何在Ktor中接收JSON对象? [英] How to receive JSON object in Ktor?
问题描述
我已经定义了数据类,配置了gson并创建了rout来处理发布请求,如下所示:
I have data class defined, configured gson and created rout to handle post request as follows:
data class PurchaseOrder(val buyer: String, val seller: String,
val poNumber: String, val date: String,
val vendorReference: String)
install(ContentNegotiation) {
gson {
setDateFormat(DateFormat.LONG)
setPrettyPrinting()
}
post("/purchaseOrder"){
val po = call.receive<PurchaseOrder>()
println("purchase order: ${po.toString()}")
call.respondText("post received", contentType =
ContentType.Text.Plain)
在POST请求中发送以下JSON
the following JSON is sent in POST request
{
"PurchaseOrder" : {
"buyer": "buyer a",
"seller": "seller A",
"poNumber": "PO1234",
"date": "27-Jun-2018",
"vendorReference": "Ref1234"
}
}
输出显示所有空值.
purchase order: PurchaseOrder(buyer=null, seller=null, poNumber=null,
date=null, vendorReference=null)
从call.request.receiveChannel()读取数据确实显示正确的JSON.因此,我正在接收数据,但call.receive()似乎无法产生预期的结果.
Reading data from call.request.receiveChannel() does show correct JSON. So I am receiving the data but call.receive() does not seem to produce expected results.
手动获取JSON,并尝试按如下所示创建PurchaseOrder:
Got JSON manually and tried to create PurchaseOrder as follows bu no luck:
val channel = call.request.receiveChannel()
val ba = ByteArray(channel.availableForRead)
channel.readFully(ba)
val s = ba.toString(Charset.defaultCharset())
println(s) // prints JSON
val gson = Gson()
val po = gson.fromJson(s, PurchaseOrder::class.java)
println("buyer = ${po.buyer}" //prints null
推荐答案
问题是您已将json包装在"PurchaseOrder"
中.
The problem is that you have wrapped your json in "PurchaseOrder"
.
如果您改为发布此信息:
If you post this instead:
{
"buyer": "buyer a",
"seller": "seller A",
"poNumber": "PO1234",
"date": "27-Jun-2018",
"vendorReference": "Ref1234"
}
它正确接收以下内容:
purchase order: PurchaseOrder(buyer=buyer a, seller=seller A, poNumber=PO1234, date=27-Jun-2018, vendorReference=Ref1234)
如果您想保留json请求,则有2个选项.
If you want to keep the json request as is, you have 2 options.
-
一个自定义gson序列化程序,期望将请求包装在
PurchaseOrder
中.
像这样的包装器类:
class PurchaseOrderWrapper(
val purchaseOrder: PurchaseOrder
)
class PurchaseOrderWrapper(
val purchaseOrder: PurchaseOrder
)
然后您将收到如下信息:
call.receive<PurchaseOrderWrapper>().purchaseOrder
Then you can receive like this:
call.receive<PurchaseOrderWrapper>().purchaseOrder
这篇关于如何在Ktor中接收JSON对象?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!