java无法使用缺少的JPA derby嵌入式驱动程序类获得到DB的连接
我正在尝试使用jpa创建本地derby数据库。作为JPA实现,我使用openjpa和作为sql实现的derby
这就是坚持。xml:
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.2"
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_2.xsd">
<persistence-unit name="DataLayer"
transaction-type="RESOURCE_LOCAL">
<non-jta-data-source>DataSource</non-jta-data-source>
<properties>
<property
name="javax.persistence.schema-generation.database.action"
value="create" />
<property name="javax.persistence.jdbc.driver"
value="org.apache.derby.jdbc.EmbeddedDriver" />
<property name="javax.persistence.jdbc.url"
value="jdbc:derby:testdb" />
</properties>
</persistence-unit>
</persistence>
这是我的主要观点:
public static void main(String[] args)
{
Persistence.generateSchema("DataLayer", null);
EntityManagerFactory factory = Persistence.createEntityManagerFactory("DataLayer");
EntityManager manager = factory.createEntityManager(); // <- Exception here
}
这是我得到的异常的开始部分:
Exception in thread "main" <openjpa-3.1.2-r66d2a72 nonfatal general error> org.a
pache.openjpa.persistence.PersistenceException: There were errors initializing y
our configuration: <openjpa-3.1.2-r66d2a72 fatal user error> org.apache.openjpa.
util.UserException: A connection could not be obtained for driver class "org.apa
che.derby.jdbc.EmbeddedDriver" and URL "jdbc:derby:testdb". You may have spe
cified an invalid URL.
...
说我可能指定了一个无效的URL
完整堆栈跟踪:https://justpaste.it/3kmgo
根异常:java。lang.ClassNotFoundException:org。阿帕奇。德比。jdbc。嵌入式驱动程序
我已经在持久性中指定了EmbeddedDriver。xml,还包括Maven依赖项
根据derby的文档,我认为我的连接url和驱动程序是正确的:
- https://db.apache.org/derby/docs/10.15/devguide/rdevdvlp22102.html#rdevdvlp22102
- https://db.apache.org/derby/docs/10.15/devguide/cdevdvlp40653.html
包含的依赖项(使用Maven):
<dependency>
<groupId>org.apache.openjpa</groupId>
<artifactId>openjpa</artifactId>
<version>3.1.2</version>
</dependency>
<dependency>
<groupId>org.apache.derby</groupId>
<artifactId>derby</artifactId>
<version>10.15.2.0</version>
</dependency>
我试图将属性javax.persistence.jdbc.url
更改为jdbc:derby:testdb;create=true
,但出现了相同的异常。还尝试将javax.persistence.schema-generation.database.action
属性设置为none
# 1 楼答案
发现
org.apache.derby.jdbc.EmbeddedDriver
类不在derby
artifactid依赖项中(它有derby和derbyshared jar)。它位于derbytools中,因此包括derbytools以解决abbout missingEmbeddedDriver
类的依赖性问题:# 2 楼答案
使用Debry 10.15.2.0,嵌入式驱动程序位于Derbytools中。罐子因此必须在库和类路径中。创建了一个新的驱动程序(我删除了所有嵌入任何内容的驱动程序)。在“服务”选项卡中,右键单击驱动程序并创建新的。添加Derbytools。jar高亮显示它并单击Find按钮。给它起一个有意义的名字,它就会按预期工作。当然我也加入了德比。jar和DerbyShared。为了避免问题