JavaApacheDerby+jpa
我有嵌入式derby数据库,我与jpa合作。这是我的坚持。xml:
<?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="pers">
<class>entities.Leverancier</class>
<class>entities.Prijsproduct</class>
<class>entities.Product</class>
</persistence-unit>
</persistence>
我应该更改或添加什么以使其工作。当我现在运行代码时,我得到以下信息:
Exception in thread "main" javax.persistence.PersistenceException: No Persistence provider for EntityManager named pers
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:55)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:33)
at test.Test.main(Test.java:19)
# 1 楼答案
您的
persistence.xml
不正确。请看下面的示例:您还必须确保将JPA提供者jar文件(以及derby客户端jar)放在类路径中