Playframework：发生 JPA 错误（无法构建 EntityManagerFactory）

Question

我开始用 Java 为一个 Play 项目做贡献，下载代码，创建 Play 项目，添加库并设置所有我能做的，然后创建数据库。 最后一切似乎都正常，但是当我运行 localhost:9000 时，我收到此错误：

JPA error
@66kcmab39
Internal Server Error (500) for request GET /favicon.ico

JPA error
A JPA error occurred (Unable to build EntityManagerFactory): Unable to get the default  Bean Validation factory
play.exceptions.JPAException: Unable to build EntityManagerFactory
    at play.db.jpa.JPAPlugin.onApplicationStart(JPAPlugin.java:227)
    at play.Play.start(Play.java:427)
    at play.Play.detectChanges(Play.java:530)
    at play.Invoker$Invocation.init(Invoker.java:100)
    at Invocation.HTTP Request(Play!)
Caused by: org.hibernate.HibernateException: Unable to get the default Bean Validation factory
at org.hibernate.cfg.beanvalidation.BeanValidationActivator.applyDDL(BeanValidationActivator.java:104)
at org.hibernate.cfg.AnnotationConfiguration.applyBeanValidationConstraintsOnDDL(AnnotationConfiguration.java:477)
at org.hibernate.cfg.AnnotationConfiguration.applyConstraintsToDDL(AnnotationConfiguration.java:429)
at org.hibernate.cfg.AnnotationConfiguration.secondPassCompile(AnnotationConfiguration.java:403)
at org.hibernate.cfg.Configuration.buildMappings(Configuration.java:1206)
at org.hibernate.ejb.Ejb3Configuration.buildMappings(Ejb3Configuration.java:1459)
at org.hibernate.ejb.EventListenerConfigurator.configure(EventListenerConfigurator.java:193)
at org.hibernate.ejb.Ejb3Configuration.configure(Ejb3Configuration.java:1086)
at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:890)
at play.db.jpa.JPAPlugin.onApplicationStart(JPAPlugin.java:225)
... 4 more
Caused by: java.lang.reflect.InvocationTargetException
at org.hibernate.cfg.beanvalidation.BeanValidationActivator.applyDDL(BeanValidationActivator.java:95)
... 13 more
Caused by: org.hibernate.HibernateException: Unable to build the default ValidatorFactory
at org.hibernate.cfg.beanvalidation.TypeSafeActivator.getValidatorFactory(TypeSafeActivator.java:322)
at org.hibernate.cfg.beanvalidation.TypeSafeActivator.applyDDL(TypeSafeActivator.java:83)
... 14 more
Caused by: javax.validation.ValidationException: Unable to find a default provider
at javax.validation.Validation$GenericBootstrapImpl.configure(Validation.java:264)
at javax.validation.Validation.buildDefaultValidatorFactory(Validation.java:111)
at org.hibernate.cfg.beanvalidation.TypeSafeActivator.getValidatorFactory(TypeSafeActivator.java:319)
... 15 more

播放版本：1.1.1
MySQL5
操作系统 Ubuntu

知道可能出了什么问题吗？
谢谢
克瓦格

Answer 1

好的答案：您需要将 Hibernate Validator 添加到您的应用程序中。

Answer 2

确保 JPA 注释（例如 @Id 和 @OneToMany）是：

(1) 全部紧邻字段上方。

@Id
public Long id;

(2) 或者，全部紧接在字段的 getter 上方。

private Long id;

@Id
public Long getId(){
    return id;
}

使用组合将导致您看到的错误。

// ERROR

@Id
private Long id;

private List<Child> children;


public Long getId(){
    return id;
}

@OneToMany
public List<Child> getChildren(){
    return id;
}

请注意，一些注释，例如：

@Constraints.Required

@Formats.DateTime(pattern="yyyy-MM-dd")

等...

必须紧接在字段名称上方。你不能把它们放在吸气剂之上。但没关系。

Answer 3

作为补充，为了添加验证器，请将其添加到您的 dependency.yml

应用程序依赖项

# Application dependencies

require:
    - play
    - org.hibernate -> hibernate-core 3.6.9.Final:
        force: true
    - org.hibernate -> hibernate-validator 4.2.0.Final