问题
I have the following function that uses the reactivemongo driver and actually does a good job writing to the database.
def writeDocument() = {
val document = BSONDocument(
"firstName" -> "Stephane",
"lastName" -> "Godbillon",
"age" -> 29)
val future = collection.insert(document)
future.onComplete {
case Failure(e) => throw e
case Success(result) => {
println("successfully inserted document with result = " + result)
}
}
}
But the limitation of that function is that the JSON is hardcoded into a BSONDocument. How can I change it so that I can pass any JSON String into the function?
Question in short: How do I convert a JSON String into a BSONDocument?
Update 2:
package controllers
//import play.api.libs.json._
//import reactivemongo.bson._
//import play.api.libs.json.Json
import scala.util.{Success, Failure}
import reactivemongo.api._
//import scala.concurrent.ExecutionContext.Implicits.global
import play.modules.reactivemongo.json.collection._
import reactivemongo.play.json._
object Mongo {
//val collection = connect()
def collection: JSONCollection = {
val driver = new MongoDriver
val connection = driver.connection(List("localhost"))
val db = connection("superman")
db.collection[JSONCollection]("IncomingRequests")
}
// TODO: Make this work with any JSON String
def writeDocument() = {
val jsonString = """{
| "guid": "alkshdlkasjd-ioqweuoiquew-123132",
| "title": "Hello-2016",
| "year": 2016,
| "action": "POST",
| "start": "2016-12-20",
| "stop": "2016-12-30"}"""
val document = Json.parse(jsonString)
val future = collection.insert(document)
future.onComplete {
case Failure(e) => throw e
case Success(result) => {
println("successfully inserted document with result = " + result)
}
}
}
}
The problem now is that import reactivemongo.play.json._ is treated as an unused import (on my IntelliJ) and I still get the following error
[info] Compiling 9 Scala sources and 1 Java source to /Users/superman/target/scala-2.11/classes...
[error] /Users/superman/app/controllers/Mongo.scala:89: No Json serializer as JsObject found for type play.api.libs.json.JsValue. Try to implement an implicit OWrites or OFormat for this type.
[error] Error occurred in an application involving default arguments.
[error] val future = collection.insert(document)
[error] ^
[error] one error found
[error] (compile:compileIncremental) Compilation failed
[error] application -
! @6oo00g47n - Internal server error, for (POST) [/validateJson] ->
play.sbt.PlayExceptions$CompilationException: Compilation error[No Json serializer as JsObject found for type play.api.libs.json.JsValue. Try to implement an implicit OWrites or OFormat for this type.
Error occurred in an application involving default arguments.]
at play.sbt.PlayExceptions$CompilationException$.apply(PlayExceptions.scala:27) ~[na:na]
at play.sbt.PlayExceptions$CompilationException$.apply(PlayExceptions.scala:27) ~[na:na]
at scala.Option.map(Option.scala:145) ~[scala-library-2.11.6.jar:na]
at play.sbt.run.PlayReload$$anonfun$taskFailureHandler$1.apply(PlayReload.scala:49) ~[na:na]
at play.sbt.run.PlayReload$$anonfun$taskFailureHandler$1.apply(PlayReload.scala:44) ~[na:na]
at scala.Option.map(Option.scala:145) ~[scala-library-2.11.6.jar:na]
at play.sbt.run.PlayReload$.taskFailureHandler(PlayReload.scala:44) ~[na:na]
at play.sbt.run.PlayReload$.compileFailure(PlayReload.scala:40) ~[na:na]
at play.sbt.run.PlayReload$$anonfun$compile$1.apply(PlayReload.scala:17) ~[na:na]
at play.sbt.run.PlayReload$$anonfun$compile$1.apply(PlayReload.scala:17) ~[na:na]
回答1:
First, you could serialize your model classes as BSON using reactivemongo. Check docs to see how.
If you want to make a BSONDocument from String through play json you can use
val playJson: JsValue = Json.parse(jsonString)
val bson: BSONDocument = play.modules.reactivemongo.json.BSONFormats.reads(playJson).get
Edit
I found more in the docs here:
http://reactivemongo.org/releases/0.11/documentation/tutorial/play2.html
you can import those two
import reactivemongo.play.json._
import play.modules.reactivemongo.json.collection._
Instead of using the default Collection implementation (which interacts with BSON structures + BSONReader/BSONWriter), we use a specialized implementation that works with JsObject + Reads/Writes.
So you create specialized collection like this (must be def, not val):
def collection: JSONCollection = db.collection[JSONCollection]("persons")
and from now on you can use it with play json, instead of BSON, so simply passing in Json.parse(jsonString) as a document to insert should work. You can see more examples in the link.
Edit 2 I got your code to compile:
package controllers
import play.api.libs.concurrent.Execution.Implicits._
import play.api.libs.json._
import play.modules.reactivemongo.json.collection.{JSONCollection, _}
import reactivemongo.api.MongoDriver
import reactivemongo.play.json._
import play.api.libs.json.Reads._
import scala.util.{Failure, Success}
object Mongo {
def collection: JSONCollection = {
val driver = new MongoDriver
val connection = driver.connection(List("localhost"))
val db = connection("superman")
db.collection[JSONCollection]("IncomingRequests")
}
def writeDocument() = {
val jsonString = """{
| "guid": "alkshdlkasjd-ioqweuoiquew-123132",
| "title": "Hello-2016",
| "year": 2016,
| "action": "POST",
| "start": "2016-12-20",
| "stop": "2016-12-30"}"""
val document = Json.parse(jsonString).as[JsObject]
val future = collection.insert(document)
future.onComplete {
case Failure(e) => throw e
case Success(result) =>
println("successfully inserted document with result = " + result)
}
}
}
the important import is
import play.api.libs.json.Reads._
and you need JsObject, not just any JsValue
val document = Json.parse(jsonString).as[JsObject]
回答2:
The ReactiveMongo release note notes:
When using the support for Play JSON, if the previous error occurs, it necessary to make sure import reactivemongo.play.json._ is used, to import default BSON/JSON conversions.
来源：https://stackoverflow.com/questions/34818582/how-to-convert-json-string-to-a-bsondocument