带有嵌入式 H2 的 Tomcat WebApp ： 数据库可能已被使用： "Locked by another process"

Question

我正在嵌入式H2数据库上使用Hibernate开发Maven Spring Boot web应用程序。该应用程序使用Maven目标tomcat7:从Maven Tomcat插件重新部署(tomcat7-Maven插件)部署在Tomcat8应用程序容器上。

当我第一次尝试在Tomcat上部署这个web应用程序时，我没有异常(在Tomcat重新启动之后)。

但是，当我尝试在Tomcat上重新部署此web应用程序时，会出现以下异常：

org.h2.jdbc.JdbcSQLException：数据库可能已在使用中："已锁定通过另一个过程"。可能的解决方案：关闭所有其他连接；使用服务器模式；SQL语句：空/14cfb969fb93251ff134953c65dd1f05db2ecd34c6b[90020-145]

hibernate.cfg.xml

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<!-- Database connection settings -->
<property name="connection.driver_class">org.h2.Driver</property>
<property name="connection.url">jdbc:h2:file:d:/Profiles/mBaye/Developement/Run/spring-boot-web-seed-dev/db/springbootwebui;DB_CLOSE_DELAY=0;MVCC=TRUE</property>
<property name="connection.username">sa</property>
<property name="connection.password"/>
<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>
<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.H2Dialect</property>
<!-- Disable the second-level cache  -->
<property name="cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</property>
<!-- Echo all executed SQL to stdout -->
<property name="show_sql">true</property>
<!-- Drop and re-create the database schema on startup -->
<!-- <property name="hbm2ddl.auto">create</property> -->
<!-- Update the database schema on startup -->
<property name="hbm2ddl.auto">update</property>
<mapping resource="app/Greeting.hbm.xml"/>
</session-factory>
</hibernate-configuration>

GreetingController.java

@Controller
public class GreetingController {
private static Logger logger ;
// A SessionFactory is set up once for an application
private static final SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
[...]
private Greeting saveGreeting(Greeting greeting) {
logger.info(new StringBuilder("greeting=").append(greeting.toString()).toString());
Session session = null;
Greeting ret = null;
try {
session = sessionFactory.openSession();
session.beginTransaction();
session.save( greeting );
session.getTransaction().commit();
// Return result
ret = greeting ;
} catch (Exception e) {
logger.log(Level.SEVERE, new StringBuilder("Failed to save ").append(greeting.toString()).toString(), e);
} finally {
session.close();
}
if (ret != null) {
logger.info(new StringBuilder("ret=").append(ret.toString()).toString());   
} else {
logger.info(new StringBuilder("ret=null").toString());
}
return ret ;
}
[...]
}

我在其他主题上读到，当虚拟机正确退出时，数据库连接会自动关闭(来源：关闭H2的正确方法是什么？)

我认为，当应用程序部署在Tomcat上时，数据库连接由Tomcat保持。

我想找到一种正确的方法来关闭Tomcat重新部署时的所有数据库连接。

提前谢谢。

Answer 1

我终于找到了解决方案！：)

我将H2数据库连接URL的设置更改为：

<property name="connection.url">jdbc:h2:file:d:/Profiles/mBaye/Developement/Run/spring-boot-web-seed-dev/db/springbootwebui;MVCC=TRUE;DB_CLOSE_ON_EXIT=TRUE;FILE_LOCK=NO</property>

hibernate.cfg.xml

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<!-- Database connection settings -->
<property name="connection.driver_class">org.h2.Driver</property>
<property name="connection.url">jdbc:h2:file:d:/Profiles/mBaye/Developement/Run/spring-boot-web-seed-dev/db/springbootwebui;MVCC=TRUE;DB_CLOSE_ON_EXIT=TRUE;FILE_LOCK=NO</property>
<property name="connection.username">sa</property>
<property name="connection.password"/>
<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>
<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.H2Dialect</property>
<!-- Disable the second-level cache  -->
<property name="cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</property>
<!-- Echo all executed SQL to stdout -->
<property name="show_sql">true</property>
<!-- Drop and re-create the database schema on startup -->
<!-- <property name="hbm2ddl.auto">create</property> -->
<!-- Update the database schema on startup -->
<property name="hbm2ddl.auto">update</property>
<mapping resource="app/Greeting.hbm.xml"/>
</session-factory>
</hibernate-configuration>

我不确定这是否是最好的解决方案，但它确实有效。

Answer 2

H2在所有连接都关闭时关闭数据库。关闭连接池中的所有连接对我有效。

Answer 3

关闭连接对我来说也很有效，在没有意识到的情况下打开了多个连接。