Question

我尝试构建这个jpa项目但遇到了同样的错误。我更新了，一切都还没改变。我错过了什么？我只在库中使用EclipseLink（JPA 2.0）。 NetBeans IDE 7.2。

An annotation processor threw an uncaught exception.
Consult the following stack trace for details.
java.lang.RuntimeException: Exception [EclipseLink-25008] (Eclipse Persistence Services - 2.3.2.v20111125-r10461): org.eclipse.persistence.exceptions.XMLMarshalException
Exception Description: A descriptor with default root element {http://xmlns.jcp.org/xml/ns/persistence}persistence was not found in the project
    at org.eclipse.persistence.internal.jpa.modelgen.CanonicalModelProcessor.process(CanonicalModelProcessor.java:407)
    .
    .
    .

    at org.apache.tools.ant.module.run.TargetExecutor.run(TargetExecutor.java:541)
    at org.netbeans.core.execution.RunClassThread.run(RunClassThread.java:153)
Caused by: Exception [EclipseLink-25008] (Eclipse Persistence Services - 2.3.2.v20111125-r10461): org.eclipse.persistence.exceptions.XMLMarshalException
Exception Description: A descriptor with default root element {http://xmlns.jcp.org/xml/ns/persistence}persistence was not found in the project
    at org.eclipse.persistence.exceptions.XMLMarshalException.noDescriptorWithMatchingRootElement(XMLMarshalException.java:129)
    .
    .
    .

    at org.eclipse.persistence.internal.jpa.modelgen.objects.PersistenceUnitReader.<init>(PersistenceUnitReader.java:71)
    at org.eclipse.persistence.internal.jpa.modelgen.CanonicalModelProcessor.process(CanonicalModelProcessor.java:376)
    ... 49 more
C:\Users\drhorvath57\Desktop\nyomt\PizzaJPA\PizzaJPA\nbproject\build-impl.xml:926: The following error occurred while executing this line:
C:\Users\drhorvath57\Desktop\nyomt\PizzaJPA\PizzaJPA\nbproject\build-impl.xml:268: Compile failed; see the compiler error output for details.
BUILD FAILED (total time: 1 second)

的persistence.xml：

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1" xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">
  <persistence-unit name="PizzaJPAPU" transaction-type="RESOURCE_LOCAL">
    <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
    <class>logic.entity.Pizza</class>
    <class>logic.entity.Topping</class>
    <class>logic.entity.Combination</class>
    <properties>
      <property name="javax.persistence.jdbc.url" value="jdbc:derby://localhost:1527/PizzaJPA"/>
      <property name="javax.persistence.jdbc.password" value="APP"/>
      <property name="javax.persistence.jdbc.driver" value="org.apache.derby.jdbc.ClientDriver"/>
      <property name="javax.persistence.jdbc.user" value="APP"/>
      <property name="eclipselink.ddl-generation" value="create-tables"/>
    </properties>
  </persistence-unit>
</persistence>

Answer 1

您要么缺少persistence.xml，要么格式不正确。如果您不确定如何创建文件，请查看example in eclipselink's site。

<强> **** **** EDIT

如果您使用的是Netbeans，则应检查IDE文档，了解如何生成persistence.xml文件，而不是自己创建。

Answer 2

我看到您正在使用带schema version 2.1的persistence.xml文件，但是使用了JPA API 2.0版。因此，更新到更新的API或更改persistence.xml文件以符合JPA 2.0版本。

RunTimeException原因是什么？

2 个答案: