尝试保存我的表单时出现 NullPointerException

Question

我是 PlayFramework 的新手，我正在学习 Udemy 上的视频课程。但是，他们的 Play 版本是 2.3.9，我正在尝试使用 2.5.4 版本；

当我尝试保存我的表单时，出现以下错误：

play.api.http.HttpErrorHandlerExceptions$$anon: Execution exception[[CompletionException: java.lang.NullPointerException]]
    at play.api.http.HttpErrorHandlerExceptions$.throwableToUsefulException(HttpErrorHandler.scala:280)
    at play.api.http.DefaultHttpErrorHandler.onServerError(HttpErrorHandler.scala:206)
    at play.api.GlobalSettings$class.onError(GlobalSettings.scala:160)
    at play.api.DefaultGlobal$.onError(GlobalSettings.scala:188)
    at play.api.http.GlobalSettingsHttpErrorHandler.onServerError(HttpErrorHandler.scala:98)
    at play.core.server.netty.PlayRequestHandler$$anonfun$$anonfun$apply.applyOrElse(PlayRequestHandler.scala:100)
    at play.core.server.netty.PlayRequestHandler$$anonfun$$anonfun$apply.applyOrElse(PlayRequestHandler.scala:99)
    at scala.concurrent.Future$$anonfun$recoverWith.apply(Future.scala:344)
    at scala.concurrent.Future$$anonfun$recoverWith.apply(Future.scala:343)
    at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:32)
Caused by: java.util.concurrent.CompletionException: java.lang.NullPointerException
    at java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:292)
    at java.util.concurrent.CompletableFuture.completeThrowable(CompletableFuture.java:308)
    at java.util.concurrent.CompletableFuture.uniApply(CompletableFuture.java:593)
    at java.util.concurrent.CompletableFuture$UniApply.tryFire(CompletableFuture.java:577)
    at java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:474)
    at java.util.concurrent.CompletableFuture.completeExceptionally(CompletableFuture.java:1977)
    at scala.concurrent.java8.FuturesConvertersImpl$CF.apply(FutureConvertersImpl.scala:21)
    at scala.concurrent.java8.FuturesConvertersImpl$CF.apply(FutureConvertersImpl.scala:18)
    at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:32)
    at scala.concurrent.BatchingExecutor$Batch$$anonfun$run.processBatch(BatchingExecutor.scala:63)
Caused by: java.lang.NullPointerException: null
    at com.avaje.ebean.Model.save(Model.java:208)
    at controllers.Services.save(Services.java:28)
    at router.Routes$$anonfun$routes$$anonfun$applyOrElse$$anonfun$apply.apply(Routes.scala:227)
    at router.Routes$$anonfun$routes$$anonfun$applyOrElse$$anonfun$apply.apply(Routes.scala:227)
    at play.core.routing.HandlerInvokerFactory$$anon.resultCall(HandlerInvoker.scala:157)
    at play.core.routing.HandlerInvokerFactory$$anon.resultCall(HandlerInvoker.scala:156)
    at play.core.routing.HandlerInvokerFactory$JavaActionInvokerFactory$$anon$$anon$$anon.invocation(HandlerInvoker.scala:136)
    at play.core.j.JavaAction$$anon.call(JavaAction.scala:73)
    at play.http.HttpRequestHandler.call(HttpRequestHandler.java:54)
    at play.core.j.JavaAction$$anonfun.apply(JavaAction.scala:108)

我的表格：

@(serviceForm : Form[Service])
@import helper._


@main("Service info"){
  <h1>Service Information</h1>
  @helper.form(action = routes.Services.save()){
    <fieldset>
      <legend>Service</legend>
      @helper.inputText(serviceForm.field("code"), '_label -> "Code")
      @helper.inputText(serviceForm.field("description"), '_label -> "Description")
    </fieldset>
    <input type="submit" value="Save"/>
  }
}

我的模特：

@Entity
public class Service extends Model {
    @Id
    public String code;
    public String description;

    public String getCode() {
        return code;
    }

    public void setCode(String code) {
        this.code = code;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }
}

我的控制器：

public class Services extends Controller {

    @Inject FormFactory formFactory;

    public Result list(){
        return TODO;
    }

    public Result addService(){
        Form<Service> serviceForm = formFactory.form(Service.class);
        return ok(info.render(serviceForm));
    }

    public Result save(){
        Form<Service> serviceForm = formFactory.form(Service.class);
        Service service = serviceForm.bindFromRequest().get();
        service.save();

        return  redirect(routes.Services.addService());
    }
}

我真的不知道该何去何从。 Google 上没有多少帖子讨论这个。任何帮助都会很棒！

编辑

Answer 1

这有帮助吗？

Issue with bindFromRequest in Play! Framework 2.3

I have been struggling with exactly the same problem: bindFromRequest returned nulls for "name" field. I did exactly the same what a guy in this Play for Java introduction video did: youtube.com/watch?v=bLrmnjPQsZc . But still no luck. I've been working on Windows 7 with JDK 1.8. IDE: Eclipse 4.4.0. And I run activator through cygwin.

This is what solved the problem for me:

In Eclipse: Project -> Build Automatically - > turn off In cygwin: ./activator clean; ./activator compile; ./activator run; After this, bindFromRequest binds name correctly and puts it into the database.

Answer 2

对于那些可能有相同或相关问题的人。。基本上，我的问题是 Ebean 插件版本。

此外，您可以在我的存储库中看到我的更改 here。

尝试保存我的表单时出现 NullPointerException

NullPointerException when trying to save my Form

java

playframework

playframework-2.0