Question

我是java-ee世界的新手。我尝试实现一个java-ee应用程序。我在配置persistence.xml时遇到了一些麻烦。我希望默认的java h2：mem是我的持久性单元。 Hier是我的persistence.xml

<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/persistence 
            http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"
    version="1.0">

    <persistence-unit name="customerDatabase">
        <description>My Customer-DB</description>
    </persistence-unit>
    <datasource jndi-name="java:jboss/datasources/ExampleDS"
        pool-name="ExampleDS" enabled="true" use-java-context="true">
        <connection-url>jdbc:h2:mem:test;DB_CLOSE_DELAY=-1</connection-url>
        <driver>h2</driver>
        <security>
            <user-name>sa</user-name>
            <password>sa</password>
        </security>
    </datasource>
    <drivers>
        <driver name="h2" module="com.h2database.h2">
            <xa-datasource-class>org.h2.jdbcx.JdbcDataSource</xa-datasource-class>
        </driver>
    </drivers>
</persistence>

它出了问题，因为我收到了错误：

cvc-complex-type.2.4.a: Invalid content was found starting with element 'datasource'. One of '{"http://java.sun.com/xml/ns/persistence":persistence-unit}' 
 is expected.

persistence.xml错过了什么？

我更改了我的提供程序，我现在正在使用hibernate ...现在我从其他订单中收到错误。有人可以帮忙吗？

11:21:46,092 ERROR [org.jboss.msc.service.fail] (ServerService Thread Pool -- 59) MSC000001: Failed to start service jboss.persistenceunit."javaee7-master.war#customerDatabase": org.jboss.msc.service.StartException in service jboss.persistenceunit."javaee7-master.war#customerDatabase": javax.persistence.PersistenceException: [PersistenceUnit: customerDatabase] Unable to build Hibernate SessionFactory
    at org.jboss.as.jpa.service.PersistenceUnitServiceImpl$1$1.run(PersistenceUnitServiceImpl.java:172)
    at org.jboss.as.jpa.service.PersistenceUnitServiceImpl$1$1.run(PersistenceUnitServiceImpl.java:117)
    at org.wildfly.security.manager.WildFlySecurityManager.doChecked(WildFlySecurityManager.java:665)
    at org.jboss.as.jpa.service.PersistenceUnitServiceImpl$1.run(PersistenceUnitServiceImpl.java:182)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)
    at org.jboss.threads.JBossThread.run(JBossThread.java:320)
Caused by: javax.persistence.PersistenceException: [PersistenceUnit: customerDatabase] Unable to build Hibernate SessionFactory
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.persistenceException(EntityManagerFactoryBuilderImpl.java:1249)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.access$600(EntityManagerFactoryBuilderImpl.java:120)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl$4.perform(EntityManagerFactoryBuilderImpl.java:860)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl$4.perform(EntityManagerFactoryBuilderImpl.java:850)
    at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.withTccl(ClassLoaderServiceImpl.java:425)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:849)
    at org.jboss.as.jpa.hibernate4.TwoPhaseBootstrapImpl.build(TwoPhaseBootstrapImpl.java:44)
    at org.jboss.as.jpa.service.PersistenceUnitServiceImpl$1$1.run(PersistenceUnitServiceImpl.java:154)
    ... 7 more
Caused by: org.hibernate.AnnotationException: No identifier specified for entity: de.ostfalia.entity.Customer
    at org.hibernate.cfg.InheritanceState.determineDefaultAccessType(InheritanceState.java:277)
    at org.hibernate.cfg.InheritanceState.getElementsToProcess(InheritanceState.java:224)
    at org.hibernate.cfg.AnnotationBinder.bindClass(AnnotationBinder.java:775)
    at org.hibernate.cfg.Configuration$MetadataSourceQueue.processAnnotatedClassesQueue(Configuration.java:3845)
    at org.hibernate.cfg.Configuration$MetadataSourceQueue.processMetadata(Configuration.java:3799)
    at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1412)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1846)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl$4.perform(EntityManagerFactoryBuilderImpl.java:857)
    ... 12 more

11:21:46,098 ERROR [org.jboss.as.controller.management-operation] (Controller Boot Thread) WFLYCTL0013: Operation ("deploy") failed - address: ([("deployment" => "javaee7-master.war")]) - failure description: {"WFLYCTL0080: Failed services" => {"jboss.persistenceunit.\"javaee7-master.war#customerDatabase\"" => "org.jboss.msc.service.StartException in service jboss.persistenceunit.\"javaee7-master.war#customerDatabase\": javax.persistence.PersistenceException: [PersistenceUnit: customerDatabase] Unable to build Hibernate SessionFactory
    Caused by: javax.persistence.PersistenceException: [PersistenceUnit: customerDatabase] Unable to build Hibernate SessionFactory
    Caused by: org.hibernate.AnnotationException: No identifier specified for entity: de.ostfalia.entity.Customer"}}
11:21:46,197 INFO  [org.jboss.as.server] (ServerService Thread Pool -- 34) WFLYSRV0010: Deployed "postgresql-9.4-1203.jdbc42.jar" (runtime-name : "postgresql-9.4-1203.jdbc42.jar")
11:21:46,198 INFO  [org.jboss.as.server] (ServerService Thread Pool -- 34) WFLYSRV0010: Deployed "javaee7-master.war" (runtime-name : "javaee7-master.war")
11:21:46,200 INFO  [org.jboss.as.controller] (Controller Boot Thread) WFLYCTL0183: Service status report
WFLYCTL0186:   Services which failed to start:      service jboss.persistenceunit."javaee7-master.war#customerDatabase": org.jboss.msc.service.StartException in service jboss.persistenceunit."javaee7-master.war#customerDatabase": javax.persistence.PersistenceException: [PersistenceUnit: customerDatabase] Unable to build Hibernate SessionFactory

Answer 1

根据官方架构，<persistence>元素只能包含persistence-unit个元素。我建议你从JPA 1.0升级到2.0（需要Java 6）或2.1（需要Java 7）。示例persistence.xml 2.1如下：

<?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="customerDatabase" transaction-type="RESOURCE_LOCAL">
    <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
    <non-jta-data-source>java:jboss/datasources/ExampleDS</non-jta-data-source>
    <exclude-unlisted-classes>false</exclude-unlisted-classes>
    <properties>
      <property name="javax.persistence.jdbc.driver" value="org.h2.Driver"/>
      <property name="javax.persistence.jdbc.url" value="jdbc:h2:mem:test;DB_CLOSE_DELAY=-1"/>
      <property name="javax.persistence.jdbc.user" value="sa"/>
      <property name="javax.persistence.jdbc.password" value="sa"/>
    </properties>
  </persistence-unit>
</persistence>

此配置假设您的应用程序从其他配置获取java:jboss/datasources/ExampleDS数据源，例如在Apache Tomcat中，它将位于context.xml中，并且此示例中列出的属性不是必需的。
如果您不使用EclipseLink库，则提供程序会有所不同在您的情况下，non-jta-data-source可能必须是jta-data-source。

更新

您现在收到的错误来自No identifier specified for entity: de.ostfalia.entity.Customer。您需要确保所有实体类都具有正确指定的Id列。如果您使用JPA注释，那将是@Id注释。如果数据库自动为该表的插入分配ID（最常见的情况），您可能还需要@GeneratedValue。还可以选择通过mapping.xml文件指定它们。这些教程将为您提供好的示例http://www.tutorialspoint.com/jpa/jpa_orm_components.htm http://www.javaworld.com/article/2077817/java-se/understanding-jpa-part-1-the-object-oriented-paradigm-of-data-persistence.html

我学到很多困难的一点是，每次执行EntityManager em = entityManagerFactory.createEntityManager();时，无论您是否已经提交或回滚交易，您最终都必须em.close()，意味着您还必须捕获可能发生的任何Throwable。在我们的网络应用程序中，我们使用javax.servlet.Filter（仅适用于webapps）为所有网址执行此操作。如果在没有活动的情况下将其打开太长时间，数据库最终将丢弃连接（具体可能不会在H2中发生），并且在重新启动服务器之前线程将无法使用。

使用H2-mem作为持久性单元

1 个答案: