如何解决jpa资源无效

Question

我使用jpa作为数据库连接方法。我使用的数据库是Derby。但是当我在glassfish服务器上部署时，我总是遇到以下错误。

Severe:   Exception while preparing the app : Invalid resource : java:app/UserDemoDB__pm

我知道错误是关于资源jndi名称但我不知道如何正确设置它。 下面是我的persistence.xml文件：

<?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="UserDemoPU" transaction-type="JTA">
    <jta-data-source>java:app/UserDemoDB</jta-data-source>
    <class>homesoft.userdemo.entities.User</class>
    <exclude-unlisted-classes>true</exclude-unlisted-classes>
    <properties>
      <property name="javax.persistence.schema-generation.database.action" value="create"/>
    </properties>
  </persistence-unit>
</persistence>

以下是我的glassfish-resources.xml：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE resources PUBLIC "-//GlassFish.org//DTD GlassFish Application Server 3.1 Resource Definitions//EN" "http://glassfish.org/dtds/glassfish-resources_1_5.dtd">
<resources>
    <jdbc-connection-pool allow-non-component-callers="false" associate-with-thread="false" connection-creation-retry-attempts="0" connection-creation-retry-interval-in-seconds="10" connection-leak-reclaim="false" connection-leak-timeout-in-seconds="0" connection-validation-method="auto-commit" datasource-classname="org.apache.derby.jdbc.ClientDataSource" fail-all-connections="false" idle-timeout-in-seconds="300" is-connection-validation-required="false" is-isolation-level-guaranteed="true" lazy-connection-association="false" lazy-connection-enlistment="false" match-connections="false" max-connection-usage-count="0" max-pool-size="32" max-wait-time-in-millis="60000" name="derby_net_UserDemoDB_appPool" non-transactional-connections="false" pool-resize-quantity="2" res-type="javax.sql.DataSource" statement-timeout-in-seconds="-1" steady-pool-size="8" validate-atmost-once-period-in-seconds="0" wrap-jdbc-objects="false">
        <property name="serverName" value="localhost"/>
        <property name="portNumber" value="1527"/>
        <property name="databaseName" value="UserDemoDB"/>
        <property name="User" value="app"/>
        <property name="Password" value="app"/>
        <property name="URL" value="jdbc:derby://localhost:1527/UserDemoDB"/>
        <property name="driverClass" value="org.apache.derby.jdbc.ClientDriver"/>
    </jdbc-connection-pool>
    <jdbc-resource enabled="true" jndi-name="java:app/UserDemoDB" object-type="user" pool-name="derby_net_UserDemoDB_appPool"/>
</resources>

我还应该为使用jndi资源配置什么。