Question

在tomcat中设置基本Web应用程序时，我们遇到“EntityManager名为persistence.xml的无持久性提供程序”异常。

我们使用eclipselink作为JPA Provider，JPA作为一个单独的项目创建，jar包含在Web应用程序的WEB-INF / lib文件夹中。

部署时WAR包含WEB-INF / lib文件夹中的jar，而persistence.xml存在于jar的META-INF文件夹中。

非常感谢任何有关如何克服这个问题的线索。

下面是堆栈跟踪，

javax.persistence.PersistenceException: No Persistence provider for EntityManager named persistence.xml
    at javax.persistence.Persistence.createEntityManagerFactory(Unknown Source)
    at javax.persistence.Persistence.createEntityManagerFactory(Unknown Source)
    at com.abc.servlet.TestServlet.doGet(TestServlet.java:38)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:108)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:522)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:620)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:1110)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:785)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1425)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:745)

persistence.xml如下所示，

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" 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_2_0.xsd">
    <persistence-unit name="persistence" transaction-type="RESOURCE_LOCAL">
        <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
        <class>com.poc.Person</class>
        <shared-cache-mode>NONE</shared-cache-mode>
        <properties>
            <property name="javax.persistence.jdbc.driver" value="oracle.jdbc.OracleDriver"/>
            <property name="javax.persistence.jdbc.user" value="MASKED"/>           
            <property name="javax.persistence.jdbc.password" value="MASKED"/>
            <property name="javax.persistence.jdbc.url" value="MASKED"/>
            <property name="eclipelink.logging.level" value="DEBUG"/>
            <property name="eclipselink.ddl-generation.output-mode " value="sql-script"/>
            <property name="eclipselink.logging.level.sql" value="ALL"/>
            <property name="eclipselink.logging.parameters" value="true"/>  
            <property name="eclipselink.query-results-cache" value="false"/>        
        </properties>               
    </persistence-unit> 
</persistence>

尝试在Tomcat 9上部署（我在Tomcat 7和8上也发现了类似的问题）。 eclipse链接jar的版本是2.5.0

Answer 1

问题是因为类路径中存在xerces * .jar以及Javax.persistence * .jar和eclipselink * .jar文件。由于xerces * .jar文件，无法解析persistence.xml文件并抱怨该文件不存在，尽管它存在。

希望这有助于某人。

Tomcat中的JPA Webapp

1 个答案: