我正在使用Hibernate。如何配置persistence.xml以具有H2内存数据库?
我的 persistence.xml 是:
<?xml version="1.0" encoding="UTF-8" ?> <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" version="2.0" xmlns="http://java.sun.com/xml/ns/persistence"> <persistence-unit name="persistenceUnit" transaction-type="RESOURCE_LOCAL"> <class>com.mastertheboss.domain.Employee</class> <class>com.mastertheboss.domain.Department</class> <properties> <property name="javax.persistence.jdbc.driver" value="org.h2.Driver" /> <property name="javax.persistence.jdbc.url" value="jdbc:h2:mem:test;DB_CLOSE_DELAY=-1" /> <property name="javax.persistence.jdbc.user" value="sa" /> <property name="javax.persistence.jdbc.password" value="" /> <property name="hbm2ddl.auto" value="update" /> <property name="hibernate.dialect" value="org.hibernate.dialect.H2Dialect" /> </properties> </persistence-unit> </persistence>
但是,当我运行我的应用程序时,出现以下 错误 :
Internal Exception: org.h2.jdbc.JdbcSQLException: Table "EMPLOYEE" not found; SQL statement: SELECT ID, NAME, DEPARTMENT_ID FROM EMPLOYEE [42102-171] Error Code: 42102 Call: SELECT ID, NAME, DEPARTMENT_ID FROM EMPLOYEE Query: ReadAllQuery(referenceClass=Employee sql="SELECT ID, NAME, DEPARTMENT_ID FROM EMPLOYEE")
您应该在第一次运行应用程序时将hibernate.hbm2ddl.auto属性设置为“ create”,以创建表
<property name="hibernate.hbm2ddl.auto" value="create" />
然后(如果您不希望在每次启动时都重新创建和清空表)将其设置为“ validate”。
<property name="hibernate.hbm2ddl.auto" value="validate" />
要自动创建模式,可以将if-not-exists添加到您的连接网址中,如下所示:
<property name="hibernate.connection.url" value="jdbc:h2:~/<filename>;INIT=CREATE SCHEMA IF NOT EXISTS <schema_name>" />