当我试图将一个选项保存到包含在我的订单中的数组列表中时，会抛出空指针异常。每次用户在视图中点击选项时（）,我都尝试将每个选项保存到ORDER类中的数组列表中。该函数以正确的选项ID调用。但是，每次尝试将其保存到数组列表中时，我都会得到空异常。但它允许我更改并保存订单类中的ID和其他属性。任何帮助将不胜感激。
控制器类：
控制器类：
public static Result selectedOption(Long id) {
System.out.println("Option selected: [" + id + "] " + "[" + OptionType.find.byId(id).getName() + "]");
Session session = Http.Context.current().session();
Orders current = Orders.find.byId(Long.parseLong(session.get("current_id")));
System.out.println("SESSION ID: " + session.get("current_id"));
current.optionType.add(OptionType.find.byId(id));
current.save();
return ok(pickOptions.render("Options", OptionType.find.where().like("priority", id.toString()).findList()));
}
订单类
package models;
import java.util.ArrayList;
import java.util.List;
import javax.persistence.*;
import play.db.ebean.*;
import play.data.validation.*;
@Entity
public class Orders extends Model {
private static final long serialVersionUID = 1L;
@Id
public Long id;
@Constraints.Required
public boolean is_florida; // String so form will take leading zero's
public List<OptionType> optionType;
public static Finder<Long,Orders> find = new Finder<Long,Orders>(Long.class, Orders.class);
public Orders(boolean is_florida) {
this.is_florida = is_florida;
this.optionType = new ArrayList<OptionType>();
}
public void setIsFlorida(boolean is_florida) {
this.is_florida = is_florida;
}
public boolean getIsFlorida() {
return is_florida;
}
}
路由文件
GET /category/option/:id controllers.Builder.selectedOption(id:Long)
从视图调用脚本
<script>
$('.select_it, .myState').on('click', function(e){
var id = $(this).attr('id');
$(this).toggleClass('myState');
jsRoutes.controllers.Builder.selectedOption(id).ajax({
success : function(data) {}
});
});
</script>
初始化订单的控制器类
public static Result selectedLocation(String location) { Orders current;
if(location.equals("ma")) {
System.out.println("Setting location: [Mid-Atlantic]");
current = new Orders(false);
} else {
System.out.println("Setting location: [Florida]");
current = new Orders(true);
}
current.save();
Session session = Http.Context.current().session();
session.put("current_id", current.id.toString());
System.out.println("Storing id into current session, id: " + session.get("current_id"));
System.out.println("Create a new order in table: [" + current.id + "] isFlorida: [" + current.is_florida + "]");
return redirect(routes.Builder.pickCate("1"));
}
堆栈跟踪
2013-10-29 00:05:45,334 - [ERROR] - from play in play-internal-execution-context-1
Cannot invoke the action, eventually got an error: java.lang.NullPointerException
2013-10-29 00:05:45,341 - [ERROR] - from application in play-internal-execution-context-1
! @6g507nja5 - Internal server error, for (GET) [/category/option/1] ->
play.api.Application$$anon$1: Execution exception[[NullPointerException: null]]
at play.api.Application$class.handleError(Application.scala:293) ~[play_2.10.jar:2.2.0]
at play.api.DefaultApplication.handleError(Application.scala:399) [play_2.10.jar:2.2.0]
at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$2$$anonfun$applyOrElse$3.apply(PlayDefaultUpstreamHandler.scala:261) [play_2.10.jar:2.2.0]
at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$2$$anonfun$applyOrElse$3.apply(PlayDefaultUpstreamHandler.scala:261) [play_2.10.jar:2.2.0]
at scala.Option.map(Option.scala:145) [scala-library.jar:na]
at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$2.applyOrElse(PlayDefaultUpstreamHandler.scala:261) [play_2.10.jar:2.2.0]
at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$2.applyOrElse(PlayDefaultUpstreamHandler.scala:257) [play_2.10.jar:2.2.0]
at scala.runtime.AbstractPartialFunction.apply(AbstractPartialFunction.scala:33) [scala-library.jar:na]
at scala.concurrent.Future$$anonfun$recoverWith$1.apply(Future.scala:411) [scala-library.jar:na]
at scala.concurrent.Future$$anonfun$recoverWith$1.apply(Future.scala:408) [scala-library.jar:na]
at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:29) [scala-library.jar:na]
at play.api.libs.iteratee.Execution$$anon$1.execute(Execution.scala:43) [play-iteratees_2.10.jar:2.2.0]
at scala.concurrent.impl.CallbackRunnable.executeWithValue(Promise.scala:37) [scala-library.jar:na]
at scala.concurrent.impl.Promise$DefaultPromise.tryComplete(Promise.scala:133) [scala-library.jar:na]
at scala.concurrent.Promise$class.complete(Promise.scala:55) [scala-library.jar:na]
at scala.concurrent.impl.Promise$DefaultPromise.complete(Promise.scala:58) [scala-library.jar:na]
at scala.concurrent.Future$$anonfun$map$1.apply(Future.scala:254) [scala-library.jar:na]
at scala.concurrent.Future$$anonfun$map$1.apply(Future.scala:249) [scala-library.jar:na]
at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:29) [scala-library.jar:na]
at scala.concurrent.forkjoin.ForkJoinTask$AdaptedRunnableAction.exec(ForkJoinTask.java:1361) [scala-library.jar:na]
at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260) [scala-library.jar:na]
at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339) [scala-library.jar:na]
at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979) [scala-library.jar:na]
at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107) [scala-library.jar:na]
Caused by: java.lang.NullPointerException: null
at controllers.Builder.selectedOption(Builder.java:38) ~[na:na]
at Routes$$anonfun$routes$1$$anonfun$applyOrElse$12$$anonfun$apply$12.apply(routes_routing.scala:193) ~[na:na]
at Routes$$anonfun$routes$1$$anonfun$applyOrElse$12$$anonfun$apply$12.apply(routes_routing.scala:193) ~[na:na]
at play.core.Router$HandlerInvoker$$anon$7$$anon$2.invocation(Router.scala:183) ~[play_2.10.jar:2.2.0]
at play.core.Router$Routes$$anon$1.invocation(Router.scala:377) ~[play_2.10.jar:2.2.0]
at play.core.j.JavaAction$$anon$1.call(JavaAction.scala:56) ~[play_2.10.jar:2.2.0]
at play.core.j.JavaAction$$anon$3.apply(JavaAction.scala:91) ~[play_2.10.jar:2.2.0]
at play.core.j.JavaAction$$anon$3.apply(JavaAction.scala:90) ~[play_2.10.jar:2.2.0]
at play.core.j.FPromiseHelper$$anonfun$flatMap$1.apply(FPromiseHelper.scala:82) ~[play_2.10.jar:2.2.0]
at play.core.j.FPromiseHelper$$anonfun$flatMap$1.apply(FPromiseHelper.scala:82) ~[play_2.10.jar:2.2.0]
at scala.concurrent.Future$$anonfun$flatMap$1.apply(Future.scala:278) ~[scala-library.jar:na]
at scala.concurrent.Future$$anonfun$flatMap$1.apply(Future.scala:274) ~[scala-library.jar:na]
at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:29) [scala-library.jar:na]
at play.core.j.HttpExecutionContext$$anon$2.run(HttpExecutionContext.scala:37) ~[play_2.10.jar:2.2.0]
at akka.dispatch.TaskInvocation.run(AbstractDispatcher.scala:42) ~[akka-actor_2.10.jar:2.2.0]
at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:386) ~[akka-actor_2.10.jar:2.2.0]
... 4 common frames omitted
更新
尝试将Option类重命名为OptionType，但仍然遇到相同的错误。
当我注释掉将选项类型添加到数组时，打印输出的示例。
Setting location: [Florida]
Storing id into current session, id: 1000
Create a new order in table: [1000] isFlorida: [true]
Category selected: [Cold Subs]
Option selected: [1] [BBQ]
SESSION ID: 1000
Option selected: [2] [Chipotle]
SESSION ID: 1000
Option selected: [6] [Mayo]
SESSION ID: 1000
Option selected: [5] [Marinara]
SESSION ID: 1000
Option selected: [9] [Sweet Onion]
SESSION ID: 1000
session.get("current_id")是否返回null。 - Mikesname