ClassNotFoundException:尝试将JPA与Derby一起使用时的org.apache.derby.jdbc.EmbeddedDriver [英] ClassNotFoundException: org.apache.derby.jdbc.EmbeddedDriver when trying to use JPA with Derby
问题描述
我问了一个相关查询:如何配置和打包一个简单的Java应用程序以使用JPA
A related query I asked: How to configure & package a simple Java app to use JPA
我有一个简单的Derby数据库,可以通过WebLogic中托管的EJB连接到该数据库.现在,我想使用JPA从命令行Java应用程序连接到它.
I have a simple Derby database which I can connect to via EJBs hosted in WebLogic. Now I would like to connect to it from a command line Java app using JPA.
到目前为止,此Java代码+ persistence.xml文件引发以下错误.我在做什么错了?
So far this Java code + persistence.xml file is throwing the error below. What am I doing wrong?
我的目录布局:
C:.
│ Registrar.class
│ Registrar.java
│ TxnClient.class
│ TxnClient.java
│
└───META-INF
persistence.xml
独立客户端:
import javax.persistence.*;
public class TxnClient {
public static void main(String[] args) throws Exception {
EntityManagerFactory factory = Persistence.createEntityManagerFactory("SRS-EM");
EntityManager manager = factory.createEntityManager( );
try {
} finally {
manager.close( );
factory.close( );
}
}
}
persistence.xml
persistence.xml
<?xml version="1.0" encoding="windows-1252" ?>
<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" xmlns="http://java.sun.com/xml/ns/persistence" version="1.0">
<persistence-unit name="SRS-EM" transaction-type="JTA">
<class>Registrar</class>
<properties>
<property name="openjpa.ConnectionDriverName"
value="org.apache.derby.jdbc.EmbeddedDriver" />
<property name="openjpa.ConnectionURL"
value="jdbc:derby:C:\derby-db-files\MyDB" />
</properties>
</persistence-unit>
</persistence>
C:\ temp \ jpa> java TxnClient
C:\temp\jpa>java TxnClient
80 SRS-EM INFO [main] openjpa.Runtime - Starting BEA Kodo 4.2.0load03
221 SRS-EM INFO [main] openjpa.jdbc.JDBC - Using dictionary class "org.apache.openjpa.jdbc.sql.DerbyDictionary".
Exception in thread "main" <openjpa-1.1.0-r422266:657916 nonfatal general error>
org.apache.openjpa.persistence.PersistenceException: There were errors initializing your configuration: <openjpa-1.1.0-r422266:657916 fatal store error> org.apache.openjpa.util.StoreException: org.apache.derby.jdbc.EmbeddedDriver
at org.apache.openjpa.jdbc.schema.DataSourceFactory.newDataSource(DataSourceFactory.java:123)
at org.apache.openjpa.jdbc.conf.JDBCConfigurationImpl.createConnectionFactory(JDBCConfigurationImpl.java:776)
at org.apache.openjpa.jdbc.conf.JDBCConfigurationImpl.getConnectionFactory(JDBCConfigurationImpl.java:683)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.openjpa.lib.conf.ConfigurationImpl.instantiateAll(ConfigurationImpl.java:288)
at org.apache.openjpa.conf.OpenJPAConfigurationImpl.instantiateAll(OpenJPAConfigurationImpl.java:1409)
at org.apache.openjpa.kernel.AbstractBrokerFactory.makeReadOnly(AbstractBrokerFactory.java:646)
at org.apache.openjpa.kernel.AbstractBrokerFactory.newBroker(AbstractBrokerFactory.java:183)
at org.apache.openjpa.kernel.DelegatingBrokerFactory.newBroker(DelegatingBrokerFactory.java:142)
at org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:192)
at org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:145)
at org.apache.openjpa.persistence.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:56)
at TxnClient.main(TxnClient.java:7)
Caused by: java.lang.ClassNotFoundException: org.apache.derby.jdbc.EmbeddedDriver
at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:169)
at org.apache.openjpa.jdbc.schema.DataSourceFactory.newDataSource(DataSourceFactory.java:85)
... 15 more
推荐答案
ClassNotFoundException
表示所讨论的类(org.apache.derby.jdbc.EmbeddedDrive
)不在您的类路径中.把它(德比罐子)放在那里,然后再试一次.
ClassNotFoundException
indicates that the class in question (org.apache.derby.jdbc.EmbeddedDrive
) is not on your classpath. Put it (the derby jar) there and try again.
这篇关于ClassNotFoundException:尝试将JPA与Derby一起使用时的org.apache.derby.jdbc.EmbeddedDriver的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!