播放框架 2.4 Ebean

Play Framework 2.4 Ebean

我正在学习如何在 Play Framework 中使用 Ebean ORM,但遇到了错误。 我有很多 classes 但问题出在这两个 classes.

StockItem class:

import com.avaje.ebean.Model;
import com.google.inject.Inject;

import javax.persistence.*;

@Entity
public class StockItem extends Model{
    @Id
    private Long id;

/*

    @ManyToOne
    private Warehouse warehouse;
*/

    @ManyToOne
    private Product product;

    private Long quantity;

    public static Finder<Long,StockItem> find = new Finder<>(StockItem.class);

    public StockItem(){
        //left blank
    }

    public String toString() {
        return String.format("%d %s",quantity,product);
    }

///gettters and setters

}

仓库class:

import com.avaje.ebean.Model;
import javax.persistence.Entity;

@Entity
public class Warehouse extends Model{

    private String name;
/*

    @OneToMany(mappedBy="warehouse")
    private List<StockItem> stock;  // = new ArrayList<>();
*/

    private static Finder<Long,Warehouse> find = new Finder<>(Warehouse.class);


    public Warehouse(){
        //left blank
    }
///gettters and setters

}

如果我取消注释多行注释,我会得到这个错误:

CreationException: Unable to create injector, see the following errors:

1) Error injecting constructor, java.lang.NullPointerException
  at play.db.ebean.EbeanDynamicEvolutions.<init>(EbeanDynamicEvolutions.java:36)
  at play.db.ebean.EbeanDynamicEvolutions.class(EbeanDynamicEvolutions.java:33)
  while locating play.db.ebean.EbeanDynamicEvolutions
  at play.db.ebean.EbeanModule.bindings(EbeanModule.java:23):
Binding(class play.api.db.evolutions.DynamicEvolutions to ConstructionTarget(class play.db.ebean.EbeanDynamicEvolutions) eagerly) (via modules: com.google.inject.util.Modules$OverrideModule -> play.api.inject.guice.GuiceableModuleConversions$$anon)
  while locating play.api.db.evolutions.DynamicEvolutions
Caused by: java.lang.NullPointerException
    at com.avaje.ebeaninternal.server.persist.dmlbind.BindableAssocOne.dmlAppend(BindableAssocOne.java:38)
    at com.avaje.ebeaninternal.server.persist.dmlbind.BindableList.dmlAppend(BindableList.java:36)
    at com.avaje.ebeaninternal.server.persist.dml.UpdateMeta.genSql(UpdateMeta.java:168)
    at com.avaje.ebeaninternal.server.persist.dml.UpdateMeta.<init>(UpdateMeta.java:46)
    at com.avaje.ebeaninternal.server.persist.dml.MetaFactory.createUpdate(MetaFactory.java:71)
    at com.avaje.ebeaninternal.server.persist.dml.DmlBeanPersisterFactory.create(DmlBeanPersisterFactory.java:25)
    at com.avaje.ebeaninternal.server.deploy.BeanManagerFactory.create(BeanManagerFactory.java:22)
    at com.avaje.ebeaninternal.server.deploy.BeanDescriptorManager.initialiseAll(BeanDescriptorManager.java:347)
    at com.avaje.ebeaninternal.server.deploy.BeanDescriptorManager.deploy(BeanDescriptorManager.java:233)
    at com.avaje.ebeaninternal.server.core.InternalConfiguration.<init>(InternalConfiguration.java:119)
    at com.avaje.ebeaninternal.server.core.DefaultContainer.createServer(DefaultContainer.java:142)
    at com.avaje.ebeaninternal.server.core.DefaultContainer.createServer(DefaultContainer.java:38)
    at com.avaje.ebean.EbeanServerFactory.createInternal(EbeanServerFactory.java:81)
    at com.avaje.ebean.EbeanServerFactory.create(EbeanServerFactory.java:66)
    at play.db.ebean.EbeanDynamicEvolutions.start(EbeanDynamicEvolutions.java:53)
    at play.db.ebean.EbeanDynamicEvolutions.<init>(EbeanDynamicEvolutions.java:39)
    at play.db.ebean.EbeanDynamicEvolutions$$FastClassByGuice$c94231.newInstance(<generated>)
    at com.google.inject.internal.cglib.reflect.$FastConstructor.newInstance(FastConstructor.java:40)
    at com.google.inject.internal.DefaultConstructionProxyFactory.newInstance(DefaultConstructionProxyFactory.java:61)
    at com.google.inject.internal.ConstructorInjector.provision(ConstructorInjector.java:105)
    at com.google.inject.internal.ConstructorInjector.construct(ConstructorInjector.java:85)
    at com.google.inject.internal.ConstructorBindingImpl$Factory.get(ConstructorBindingImpl.java:267)
    at com.google.inject.internal.ProviderToInternalFactoryAdapter.call(ProviderToInternalFactoryAdapter.java:46)
    at com.google.inject.internal.InjectorImpl.callInContext(InjectorImpl.java:1103)
    at com.google.inject.internal.ProviderToInternalFactoryAdapter.get(ProviderToInternalFactoryAdapter.java:40)
    at com.google.inject.internal.SingletonScope.get(SingletonScope.java:145)
    at com.google.inject.internal.InternalFactoryToProviderAdapter.get(InternalFactoryToProviderAdapter.java:41)
    at com.google.inject.internal.FactoryProxy.get(FactoryProxy.java:56)
    at com.google.inject.internal.ProviderToInternalFactoryAdapter.call(ProviderToInternalFactoryAdapter.java:46)
    at com.google.inject.internal.InjectorImpl.callInContext(InjectorImpl.java:1103)
    at com.google.inject.internal.ProviderToInternalFactoryAdapter.get(ProviderToInternalFactoryAdapter.java:40)
    at com.google.inject.internal.SingletonScope.get(SingletonScope.java:145)
    at com.google.inject.internal.InternalFactoryToProviderAdapter.get(InternalFactoryToProviderAdapter.java:41)
    at com.google.inject.internal.InternalInjectorCreator.call(InternalInjectorCreator.java:205)
    at com.google.inject.internal.InternalInjectorCreator.call(InternalInjectorCreator.java:199)
    at com.google.inject.internal.InjectorImpl.callInContext(InjectorImpl.java:1092)
    at com.google.inject.internal.InternalInjectorCreator.loadEagerSingletons(InternalInjectorCreator.java:199)
    at com.google.inject.internal.InternalInjectorCreator.injectDynamically(InternalInjectorCreator.java:180)
    at com.google.inject.internal.InternalInjectorCreator.build(InternalInjectorCreator.java:110)
    at com.google.inject.Guice.createInjector(Guice.java:96)
    at com.google.inject.Guice.createInjector(Guice.java:73)
    at com.google.inject.Guice.createInjector(Guice.java:62)
    at play.api.inject.guice.GuiceBuilder.injector(GuiceInjectorBuilder.scala:126)
    at play.api.inject.guice.GuiceApplicationBuilder.build(GuiceApplicationBuilder.scala:93)
    at play.api.inject.guice.GuiceApplicationLoader.load(GuiceApplicationLoader.scala:21)
    at play.core.server.DevServerStart$$anonfun$mainDev$$anon$$anonfun$get$$anonfun$apply$$anonfun$$anonfun.apply(DevServerStart.scala:153)
    at play.core.server.DevServerStart$$anonfun$mainDev$$anon$$anonfun$get$$anonfun$apply$$anonfun$$anonfun.apply(DevServerStart.scala:150)
    at play.utils.Threads$.withContextClassLoader(Threads.scala:21)
    at play.core.server.DevServerStart$$anonfun$mainDev$$anon$$anonfun$get$$anonfun$apply$$anonfun.apply(DevServerStart.scala:150)
    at play.core.server.DevServerStart$$anonfun$mainDev$$anon$$anonfun$get$$anonfun$apply$$anonfun.apply(DevServerStart.scala:121)
    at scala.Option.map(Option.scala:146)
    at play.core.server.DevServerStart$$anonfun$mainDev$$anon$$anonfun$get$$anonfun$apply.apply(DevServerStart.scala:121)
    at play.core.server.DevServerStart$$anonfun$mainDev$$anon$$anonfun$get$$anonfun$apply.apply(DevServerStart.scala:119)
    at scala.util.Success.flatMap(Try.scala:230)
    at play.core.server.DevServerStart$$anonfun$mainDev$$anon$$anonfun$get.apply(DevServerStart.scala:119)
    at play.core.server.DevServerStart$$anonfun$mainDev$$anon$$anonfun$get.apply(DevServerStart.scala:111)
    at scala.concurrent.impl.Future$PromiseCompletingRunnable.liftedTree1(Future.scala:24)
    at scala.concurrent.impl.Future$PromiseCompletingRunnable.run(Future.scala:24)
    at java.util.concurrent.ForkJoinTask$RunnableExecuteAction.exec(Unknown Source)
    at java.util.concurrent.ForkJoinTask.doExec(Unknown Source)
    at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(Unknown Source)
    at java.util.concurrent.ForkJoinPool.runWorker(Unknown Source)
    at java.util.concurrent.ForkJoinWorkerThread.run(Unknown Source)

2) Error injecting constructor, java.lang.NullPointerException
  at play.db.ebean.EbeanDynamicEvolutions.<init>(EbeanDynamicEvolutions.java:36)
  at play.db.ebean.EbeanDynamicEvolutions.class(EbeanDynamicEvolutions.java:33)
  while locating play.db.ebean.EbeanDynamicEvolutions
  at play.db.ebean.EbeanModule.bindings(EbeanModule.java:23):
Binding(class play.api.db.evolutions.DynamicEvolutions to ConstructionTarget(class play.db.ebean.EbeanDynamicEvolutions) eagerly) (via modules: com.google.inject.util.Modules$OverrideModule -> play.api.inject.guice.GuiceableModuleConversions$$anon)
  while locating play.api.db.evolutions.DynamicEvolutions
  while locating play.api.db.evolutions.ApplicationEvolutionsProvider
  at play.api.db.evolutions.EvolutionsModule.bindings(EvolutionsModule.scala:22):
Binding(class play.api.db.evolutions.ApplicationEvolutions to ProviderConstructionTarget(class play.api.db.evolutions.ApplicationEvolutionsProvider) eagerly) (via modules: com.google.inject.util.Modules$OverrideModule -> play.api.inject.guice.GuiceableModuleConversions$$anon)
  while locating play.api.db.evolutions.ApplicationEvolutions
Caused by: java.lang.NullPointerException
    at com.avaje.ebeaninternal.server.persist.dmlbind.BindableAssocOne.dmlAppend(BindableAssocOne.java:38)
    at com.avaje.ebeaninternal.server.persist.dmlbind.BindableList.dmlAppend(BindableList.java:36)
    at com.avaje.ebeaninternal.server.persist.dml.UpdateMeta.genSql(UpdateMeta.java:168)
    at com.avaje.ebeaninternal.server.persist.dml.UpdateMeta.<init>(UpdateMeta.java:46)
    at com.avaje.ebeaninternal.server.persist.dml.MetaFactory.createUpdate(MetaFactory.java:71)
    at com.avaje.ebeaninternal.server.persist.dml.DmlBeanPersisterFactory.create(DmlBeanPersisterFactory.java:25)
    at com.avaje.ebeaninternal.server.deploy.BeanManagerFactory.create(BeanManagerFactory.java:22)
    at com.avaje.ebeaninternal.server.deploy.BeanDescriptorManager.initialiseAll(BeanDescriptorManager.java:347)
    at com.avaje.ebeaninternal.server.deploy.BeanDescriptorManager.deploy(BeanDescriptorManager.java:233)
    at com.avaje.ebeaninternal.server.core.InternalConfiguration.<init>(InternalConfiguration.java:119)
    at com.avaje.ebeaninternal.server.core.DefaultContainer.createServer(DefaultContainer.java:142)
    at com.avaje.ebeaninternal.server.core.DefaultContainer.createServer(DefaultContainer.java:38)
    at com.avaje.ebean.EbeanServerFactory.createInternal(EbeanServerFactory.java:81)
    at com.avaje.ebean.EbeanServerFactory.create(EbeanServerFactory.java:66)
    at play.db.ebean.EbeanDynamicEvolutions.start(EbeanDynamicEvolutions.java:53)
    at play.db.ebean.EbeanDynamicEvolutions.<init>(EbeanDynamicEvolutions.java:39)
    at play.db.ebean.EbeanDynamicEvolutions$$FastClassByGuice$c94231.newInstance(<generated>)
    at com.google.inject.internal.cglib.reflect.$FastConstructor.newInstance(FastConstructor.java:40)
    at com.google.inject.internal.DefaultConstructionProxyFactory.newInstance(DefaultConstructionProxyFactory.java:61)
    at com.google.inject.internal.ConstructorInjector.provision(ConstructorInjector.java:105)
    at com.google.inject.internal.ConstructorInjector.construct(ConstructorInjector.java:85)
    at com.google.inject.internal.ConstructorBindingImpl$Factory.get(ConstructorBindingImpl.java:267)
    at com.google.inject.internal.ProviderToInternalFactoryAdapter.call(ProviderToInternalFactoryAdapter.java:46)
    at com.google.inject.internal.InjectorImpl.callInContext(InjectorImpl.java:1103)
    at com.google.inject.internal.ProviderToInternalFactoryAdapter.get(ProviderToInternalFactoryAdapter.java:40)
    at com.google.inject.internal.SingletonScope.get(SingletonScope.java:145)
    at com.google.inject.internal.InternalFactoryToProviderAdapter.get(InternalFactoryToProviderAdapter.java:41)
    at com.google.inject.internal.FactoryProxy.get(FactoryProxy.java:56)
    at com.google.inject.internal.ProviderToInternalFactoryAdapter.call(ProviderToInternalFactoryAdapter.java:46)
    at com.google.inject.internal.InjectorImpl.callInContext(InjectorImpl.java:1103)
    at com.google.inject.internal.ProviderToInternalFactoryAdapter.get(ProviderToInternalFactoryAdapter.java:40)
    at com.google.inject.internal.SingletonScope.get(SingletonScope.java:145)
    at com.google.inject.internal.InternalFactoryToProviderAdapter.get(InternalFactoryToProviderAdapter.java:41)
    at com.google.inject.internal.InjectorImpl.call(InjectorImpl.java:1016)
    at com.google.inject.internal.InjectorImpl.callInContext(InjectorImpl.java:1103)
    at com.google.inject.internal.InjectorImpl.get(InjectorImpl.java:1012)
    at com.google.inject.internal.InjectorImpl.getInstance(InjectorImpl.java:1051)
    at play.api.inject.guice.GuiceInjector.instanceOf(GuiceInjectorBuilder.scala:321)
    at play.api.inject.guice.GuiceInjector.instanceOf(GuiceInjectorBuilder.scala:316)
    at play.api.db.evolutions.ApplicationEvolutionsProvider.get$lzycompute(EvolutionsModule.scala:53)
    at play.api.db.evolutions.ApplicationEvolutionsProvider.get(EvolutionsModule.scala:53)
    at play.api.db.evolutions.ApplicationEvolutionsProvider.get(EvolutionsModule.scala:44)
    at com.google.inject.internal.ProviderInternalFactory.provision(ProviderInternalFactory.java:81)
    at com.google.inject.internal.BoundProviderFactory.provision(BoundProviderFactory.java:72)
    at com.google.inject.internal.ProviderInternalFactory.circularGet(ProviderInternalFactory.java:61)
    at com.google.inject.internal.BoundProviderFactory.get(BoundProviderFactory.java:62)
    at com.google.inject.internal.ProviderToInternalFactoryAdapter.call(ProviderToInternalFactoryAdapter.java:46)
    at com.google.inject.internal.InjectorImpl.callInContext(InjectorImpl.java:1103)
    at com.google.inject.internal.ProviderToInternalFactoryAdapter.get(ProviderToInternalFactoryAdapter.java:40)
    at com.google.inject.internal.SingletonScope.get(SingletonScope.java:145)
    at com.google.inject.internal.InternalFactoryToProviderAdapter.get(InternalFactoryToProviderAdapter.java:41)
    at com.google.inject.internal.InternalInjectorCreator.call(InternalInjectorCreator.java:205)
    at com.google.inject.internal.InternalInjectorCreator.call(InternalInjectorCreator.java:199)
    at com.google.inject.internal.InjectorImpl.callInContext(InjectorImpl.java:1092)
    at com.google.inject.internal.InternalInjectorCreator.loadEagerSingletons(InternalInjectorCreator.java:199)
    at com.google.inject.internal.InternalInjectorCreator.injectDynamically(InternalInjectorCreator.java:180)
    at com.google.inject.internal.InternalInjectorCreator.build(InternalInjectorCreator.java:110)
    at com.google.inject.Guice.createInjector(Guice.java:96)
    at com.google.inject.Guice.createInjector(Guice.java:73)
    at com.google.inject.Guice.createInjector(Guice.java:62)
    at play.api.inject.guice.GuiceBuilder.injector(GuiceInjectorBuilder.scala:126)
    at play.api.inject.guice.GuiceApplicationBuilder.build(GuiceApplicationBuilder.scala:93)
    at play.api.inject.guice.GuiceApplicationLoader.load(GuiceApplicationLoader.scala:21)
    at play.core.server.DevServerStart$$anonfun$mainDev$$anon$$anonfun$get$$anonfun$apply$$anonfun$$anonfun.apply(DevServerStart.scala:153)
    at play.core.server.DevServerStart$$anonfun$mainDev$$anon$$anonfun$get$$anonfun$apply$$anonfun$$anonfun.apply(DevServerStart.scala:150)
    at play.utils.Threads$.withContextClassLoader(Threads.scala:21)
    at play.core.server.DevServerStart$$anonfun$mainDev$$anon$$anonfun$get$$anonfun$apply$$anonfun.apply(DevServerStart.scala:150)
    at play.core.server.DevServerStart$$anonfun$mainDev$$anon$$anonfun$get$$anonfun$apply$$anonfun.apply(DevServerStart.scala:121)
    at scala.Option.map(Option.scala:146)
    at play.core.server.DevServerStart$$anonfun$mainDev$$anon$$anonfun$get$$anonfun$apply.apply(DevServerStart.scala:121)
    at play.core.server.DevServerStart$$anonfun$mainDev$$anon$$anonfun$get$$anonfun$apply.apply(DevServerStart.scala:119)
    at scala.util.Success.flatMap(Try.scala:230)
    at play.core.server.DevServerStart$$anonfun$mainDev$$anon$$anonfun$get.apply(DevServerStart.scala:119)
    at play.core.server.DevServerStart$$anonfun$mainDev$$anon$$anonfun$get.apply(DevServerStart.scala:111)
    at scala.concurrent.impl.Future$PromiseCompletingRunnable.liftedTree1(Future.scala:24)
    at scala.concurrent.impl.Future$PromiseCompletingRunnable.run(Future.scala:24)
    at java.util.concurrent.ForkJoinTask$RunnableExecuteAction.exec(Unknown Source)
    at java.util.concurrent.ForkJoinTask.doExec(Unknown Source)
    at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(Unknown Source)
    at java.util.concurrent.ForkJoinPool.runWorker(Unknown Source)
    at java.util.concurrent.ForkJoinWorkerThread.run(Unknown Source)

2 errors

任何帮助将不胜感激。

我找到了解决办法。为遇到同样问题的其他人添加它。

我还没有在我的仓库中添加 id 变量 class。

将以下内容添加到仓库 class。

@Id
private Long id;