如何在控制器中正确传递参数？
How correctly pass parameters in controllers?
我是 Play Framework 的新人，需要一些建议。
在我的项目中，我发送了 AJAX 请求，但不幸的是 Play Framework 引发了错误，您可以在下面看到该错误。从错误消息中，您可以注意到该问题最有可能出现在控制器中。我的错误在哪里？如何修复此错误？
[error] application -
! @79mg8k016 - Internal server error, for (GET) [/] ->
play.api.UnexpectedException: Unexpected exception[CreationException: Unable to create injector, see the following errors:
1) No implementation for play.api.db.Database was bound.
while locating play.api.db.Database
for the 1st parameter of controllers.GetValuesController.<init>(GetValuesController.scala:14)
while locating controllers.GetValuesController
for the 4th parameter of router.Routes.<init>(Routes.scala:33)
at play.api.inject.RoutesProvider$.bindingsFromConfiguration(BuiltinModule.scala:121):
Binding(class router.Routes to self) (via modules: com.google.inject.util.Modules$OverrideModule -> play.api.inject.guice.GuiceableModuleConversions$$anon)
1 error]
at play.core.server.DevServerStart$$anon.reload(DevServerStart.scala:186)
at play.core.server.DevServerStart$$anon.get(DevServerStart.scala:124)
at play.core.server.AkkaHttpServer.handleRequest(AkkaHttpServer.scala:241)
at play.core.server.AkkaHttpServer.$anonfun$createServerBinding(AkkaHttpServer.scala:138)
at akka.stream.impl.fusing.MapAsyncUnordered$$anon.onPush(Ops.scala:1304)
at akka.stream.impl.fusing.GraphInterpreter.processPush(GraphInterpreter.scala:519)
at akka.stream.impl.fusing.GraphInterpreter.processEvent(GraphInterpreter.scala:482)
at akka.stream.impl.fusing.GraphInterpreter.execute(GraphInterpreter.scala:378)
at akka.stream.impl.fusing.GraphInterpreterShell.runBatch(ActorGraphInterpreter.scala:588)
at akka.stream.impl.fusing.GraphInterpreterShell$AsyncInput.execute(ActorGraphInterpreter.scala:472)
Caused by: com.google.inject.CreationException: Unable to create injector, see the following errors:
1) No implementation for play.api.db.Database was bound.
while locating play.api.db.Database
for the 1st parameter of controllers.GetValuesController.<init>(GetValuesController.scala:14)
while locating controllers.GetValuesController
for the 4th parameter of router.Routes.<init>(Routes.scala:33)
at play.api.inject.RoutesProvider$.bindingsFromConfiguration(BuiltinModule.scala:121):
Binding(class router.Routes to self) (via modules: com.google.inject.util.Modules$OverrideModule -> play.api.inject.guice.GuiceableModuleConversions$$anon)
控制器好像出了点问题。我的错误在哪里，如何解决？
我使用：
JDK 1.8.0_181
SBT 0.13.5
Scala 2.12
Play Framework 2.6.20
路线:
GET /get_values controllers.GetValuesController.get_data_from_db(start_date_time:String, end_date_time:String, city_name:String)
GetValuesController.scala:
package controllers
import javax.inject._
import akka.actor.ActorSystem
import play.api.Configuration
import play.api.mvc.{AbstractController, ControllerComponents}
import play.api.libs.ws._
import scala.concurrent.duration._
import scala.concurrent.{ExecutionContext, Future, Promise}
import services._
import play.api.db.Database
class GetValuesController@Inject()(db: Database, conf: Configuration, ws: WSClient, cc: ControllerComponents, actorSystem: ActorSystem)(implicit exec: ExecutionContext) extends AbstractController(cc) {
def get_data_from_db(start_date_time: String, end_date_time: String, city_name: String) = Action.async {
getValue(1.second, start_date_time: String, end_date_time: String, city_name: String).map {
message => Ok(message)
}
}
private def getValue(delayTime: FiniteDuration, start_date_time: String, end_date_time: String, city_name: String): Future[String] = {
val promise: Promise[String] = Promise[String]()
val service: GetValuesService = new GetValuesService(db)
actorSystem.scheduler.scheduleOnce(delayTime) {
promise.success(service.get_values(start_date_time, end_date_time, city_name))
}(actorSystem.dispatcher)
promise.future
}
}
GetValuesService.scala:
package services
import play.api.db.Database
import play.api.libs.json._
class GetYoutubeSpeedValuesService(db: Database) {
def get_youtube_speed_values(start_date_time: String, end_date_time: String, city_name: String): String ={
val SQL_STATEMENT = "SELECT " +
"table_name.\"Stamper\" AS DATE_TIME, " +
"table_name.\"CITY\" AS CITY, " +
"MAX(table_name.avg) AS MAX_SPEED " +
"FROM table_name" +
"WHERE table_name.\"CITY\"='" + city_name + "' " +
"AND (table_name.\"Stamper\" BETWEEN '" + start_date_time + "' AND '" + end_date_time + "') " +
"GROUP BY table_name.\"Stamper\", table_name.\"CITY\";"
val connection = db.getConnection()
var json_array = Json.arr()
try {
val query = connection.createStatement.executeQuery(SQL_STATEMENT)
while (query.next()) {
val json_object = Json.obj(
"DATE_TIME" -> query.getString(1),
"CITY" -> query.getString(2),
"MAX_SPEED" -> query.getString(3)
)
json_array +:= json_object
}
} finally {
connection.close()
}
println(json_array)
json_array.toString()
}
}
application.conf:
db.postgres.driver=org.postgresql.Driver
db.postgres.url="jdbc:postgresql://host:port/database_name"
db.postgres.username = "username"
db.postgres.password = "password"
Javascript:
$.ajax({
type: "POST",
url: "http://localhost:9000/get_values",
data: {
start_date_time: '2018-10-01 00:00:00',
end_date_time: '2018-10-31 23:00:00',
city_name: 'London'
},
success: function (result) {
console.log(result);
},
error: function (jqXHR, textStatus, errorThrown) {
console.log("jqXHR: " + jqXHR);
console.log("textStatus: " + textStatus);
console.log("errorThrown: " + errorThrown);
}
});
错误:
Action Not Found
For request 'POST /get_values'
同时控制器现在可以正常工作了！如果我打电话让我们说 url: http://localhost:9000/get_values?start_date_time=2018-10-01%2000:00:00&end_date_time=2018-10-31%2023:00:00&city_name=London 它 return 我 JSON 数据。
嗯，终于找到问题所在了。问题出在 application.conf 文件中。在我的例子中，我使用了下一个数据库配置：
db.default.driver=org.postgresql.Driver
db.default.url="jdbc:postgresql://host:port/database_name"
db.default.username = "username"
db.default.password = "password"
同样在 AJAX 代码中我删除了这部分：type: "POST"
我是 Play Framework 的新人，需要一些建议。
在我的项目中，我发送了 AJAX 请求，但不幸的是 Play Framework 引发了错误，您可以在下面看到该错误。从错误消息中，您可以注意到该问题最有可能出现在控制器中。我的错误在哪里？如何修复此错误？
[error] application -
! @79mg8k016 - Internal server error, for (GET) [/] ->
play.api.UnexpectedException: Unexpected exception[CreationException: Unable to create injector, see the following errors:
1) No implementation for play.api.db.Database was bound.
while locating play.api.db.Database
for the 1st parameter of controllers.GetValuesController.<init>(GetValuesController.scala:14)
while locating controllers.GetValuesController
for the 4th parameter of router.Routes.<init>(Routes.scala:33)
at play.api.inject.RoutesProvider$.bindingsFromConfiguration(BuiltinModule.scala:121):
Binding(class router.Routes to self) (via modules: com.google.inject.util.Modules$OverrideModule -> play.api.inject.guice.GuiceableModuleConversions$$anon)
1 error]
at play.core.server.DevServerStart$$anon.reload(DevServerStart.scala:186)
at play.core.server.DevServerStart$$anon.get(DevServerStart.scala:124)
at play.core.server.AkkaHttpServer.handleRequest(AkkaHttpServer.scala:241)
at play.core.server.AkkaHttpServer.$anonfun$createServerBinding(AkkaHttpServer.scala:138)
at akka.stream.impl.fusing.MapAsyncUnordered$$anon.onPush(Ops.scala:1304)
at akka.stream.impl.fusing.GraphInterpreter.processPush(GraphInterpreter.scala:519)
at akka.stream.impl.fusing.GraphInterpreter.processEvent(GraphInterpreter.scala:482)
at akka.stream.impl.fusing.GraphInterpreter.execute(GraphInterpreter.scala:378)
at akka.stream.impl.fusing.GraphInterpreterShell.runBatch(ActorGraphInterpreter.scala:588)
at akka.stream.impl.fusing.GraphInterpreterShell$AsyncInput.execute(ActorGraphInterpreter.scala:472)
Caused by: com.google.inject.CreationException: Unable to create injector, see the following errors:
1) No implementation for play.api.db.Database was bound.
while locating play.api.db.Database
for the 1st parameter of controllers.GetValuesController.<init>(GetValuesController.scala:14)
while locating controllers.GetValuesController
for the 4th parameter of router.Routes.<init>(Routes.scala:33)
at play.api.inject.RoutesProvider$.bindingsFromConfiguration(BuiltinModule.scala:121):
Binding(class router.Routes to self) (via modules: com.google.inject.util.Modules$OverrideModule -> play.api.inject.guice.GuiceableModuleConversions$$anon)
控制器好像出了点问题。我的错误在哪里，如何解决？
我使用：
JDK 1.8.0_181
SBT 0.13.5
Scala 2.12
Play Framework 2.6.20
路线:
GET /get_values controllers.GetValuesController.get_data_from_db(start_date_time:String, end_date_time:String, city_name:String)
GetValuesController.scala:
package controllers
import javax.inject._
import akka.actor.ActorSystem
import play.api.Configuration
import play.api.mvc.{AbstractController, ControllerComponents}
import play.api.libs.ws._
import scala.concurrent.duration._
import scala.concurrent.{ExecutionContext, Future, Promise}
import services._
import play.api.db.Database
class GetValuesController@Inject()(db: Database, conf: Configuration, ws: WSClient, cc: ControllerComponents, actorSystem: ActorSystem)(implicit exec: ExecutionContext) extends AbstractController(cc) {
def get_data_from_db(start_date_time: String, end_date_time: String, city_name: String) = Action.async {
getValue(1.second, start_date_time: String, end_date_time: String, city_name: String).map {
message => Ok(message)
}
}
private def getValue(delayTime: FiniteDuration, start_date_time: String, end_date_time: String, city_name: String): Future[String] = {
val promise: Promise[String] = Promise[String]()
val service: GetValuesService = new GetValuesService(db)
actorSystem.scheduler.scheduleOnce(delayTime) {
promise.success(service.get_values(start_date_time, end_date_time, city_name))
}(actorSystem.dispatcher)
promise.future
}
}
GetValuesService.scala:
package services
import play.api.db.Database
import play.api.libs.json._
class GetYoutubeSpeedValuesService(db: Database) {
def get_youtube_speed_values(start_date_time: String, end_date_time: String, city_name: String): String ={
val SQL_STATEMENT = "SELECT " +
"table_name.\"Stamper\" AS DATE_TIME, " +
"table_name.\"CITY\" AS CITY, " +
"MAX(table_name.avg) AS MAX_SPEED " +
"FROM table_name" +
"WHERE table_name.\"CITY\"='" + city_name + "' " +
"AND (table_name.\"Stamper\" BETWEEN '" + start_date_time + "' AND '" + end_date_time + "') " +
"GROUP BY table_name.\"Stamper\", table_name.\"CITY\";"
val connection = db.getConnection()
var json_array = Json.arr()
try {
val query = connection.createStatement.executeQuery(SQL_STATEMENT)
while (query.next()) {
val json_object = Json.obj(
"DATE_TIME" -> query.getString(1),
"CITY" -> query.getString(2),
"MAX_SPEED" -> query.getString(3)
)
json_array +:= json_object
}
} finally {
connection.close()
}
println(json_array)
json_array.toString()
}
}
application.conf:
db.postgres.driver=org.postgresql.Driver
db.postgres.url="jdbc:postgresql://host:port/database_name"
db.postgres.username = "username"
db.postgres.password = "password"
Javascript:
$.ajax({
type: "POST",
url: "http://localhost:9000/get_values",
data: {
start_date_time: '2018-10-01 00:00:00',
end_date_time: '2018-10-31 23:00:00',
city_name: 'London'
},
success: function (result) {
console.log(result);
},
error: function (jqXHR, textStatus, errorThrown) {
console.log("jqXHR: " + jqXHR);
console.log("textStatus: " + textStatus);
console.log("errorThrown: " + errorThrown);
}
});
错误:
Action Not Found
For request 'POST /get_values'
同时控制器现在可以正常工作了！如果我打电话让我们说 url: http://localhost:9000/get_values?start_date_time=2018-10-01%2000:00:00&end_date_time=2018-10-31%2023:00:00&city_name=London 它 return 我 JSON 数据。
嗯，终于找到问题所在了。问题出在 application.conf 文件中。在我的例子中，我使用了下一个数据库配置：
db.default.driver=org.postgresql.Driver
db.default.url="jdbc:postgresql://host:port/database_name"
db.default.username = "username"
db.default.password = "password"
同样在 AJAX 代码中我删除了这部分：type: "POST"