java - Spring 和 Tomcat : Access to DialectResolutionInfo cannot be null when 'hibernate.dialect' not set

Question

我有一个使用 Spring Repository 框架和 MySQL 数据库的应用程序。我目前已将其部署在 Tomcat 7 上。

一旦我部署并尝试登录到应用程序(第一次调用数据库)，我收到以下异常:

SEVERE: Exception sending context initialized event to listener instance of class org.springframework.web.context.ContextLoaderListener
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in URL [file:/opt/apache-tomcat-7.0.62/webapps/waypoint/WEB-INF/classes/repository-context.xml]: Invocation of init method failed; nested exception is org.hibernate.HibernateException: Access to DialectResolutionInfo cannot be null when 'hibernate.dialect' not set

我已在数据库上启用查询日志记录，并且可以确认正在对数据库中的用户对象进行查询。但是，在登录页面本身，我看到以下消息:

Your login attempt was not successful, try again.

Reason: could not extract ResultSet; SQL [n/a]; nested exception is org.hibernate.exception.SQLGrammarException: could not extract ResultSet

让事情变得有点困惑，只有当我尝试在远程服务器上部署时才会发生这种情况。当我启动 MySQL 的本地实例并在本地主机上运行 Tomcat 实例时，一切都按预期进行。

下面是我的 repository-context.xml:

    <beans:bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
    <beans:property name="driverClassName" value="com.mysql.jdbc.Driver" />
    <beans:property name="url"
        value="jdbc:mysql://localhost:3306/waypoint_dev" />
    <beans:property name="username" value="root" />
</beans:bean>

<beans:bean id="entityManagerFactory"
    class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
    <beans:property name="dataSource" ref="dataSource" />
    <beans:property name="jpaVendorAdapter">
        <beans:bean
            class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter" />
    </beans:property>
    <!-- spring based scanning for entity classes> -->
    <beans:property name="packagesToScan"
        value="com.cigna.waypoint.repository, com.cigna.waypoint.core" />
</beans:bean>

<beans:bean id="transactionManager"
    class="org.springframework.orm.jpa.JpaTransactionManager">
    <beans:property name="entityManagerFactory" ref="entityManagerFactory" />
</beans:bean>

有没有人知道是什么导致了这个问题？是否有我不知道或忘记的 Tomcat 所需的配置？

感谢您的帮助。

=== 更新 1 ====

指定方言后，我收到以下堆栈跟踪:

Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

The last packet successfully received from the server was 161,752 milliseconds ago.  The last packet sent successfully to the server was 0 milliseconds ago.
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_45]
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source) ~[na:1.8.0_45]
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) ~[na:1.8.0_45]
    at java.lang.reflect.Constructor.newInstance(Unknown Source) ~[na:1.8.0_45]
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:377) ~[mysql-connector-java-5.1.33.jar:5.1.33]
    at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1036) ~[mysql-connector-java-5.1.33.jar:5.1.33]
    at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3427) ~[mysql-connector-java-5.1.33.jar:5.1.33]
    at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3327) ~[mysql-connector-java-5.1.33.jar:5.1.33]
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3814) ~[mysql-connector-java-5.1.33.jar:5.1.33]
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2435) ~[mysql-connector-java-5.1.33.jar:5.1.33]
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2582) ~[mysql-connector-java-5.1.33.jar:5.1.33]
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2530) ~[mysql-connector-java-5.1.33.jar:5.1.33]
    at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1907) ~[mysql-connector-java-5.1.33.jar:5.1.33]
    at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:2030) ~[mysql-connector-java-5.1.33.jar:5.1.33]
    at org.apache.commons.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:96) ~[commons-dbcp-1.4.jar:1.4]
    at org.apache.commons.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:96) ~[commons-dbcp-1.4.jar:1.4]
    at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.extract(ResultSetReturnImpl.java:82) ~[hibernate-core-4.3.6.Final.jar:4.3.6.Final]
    ... 80 common frames omitted
Caused by: java.io.EOFException: Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost.
    at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:2914) ~[mysql-connector-java-5.1.33.jar:5.1.33]
    at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3337) ~[mysql-connector-java-5.1.33.jar:5.1.33]
    ... 90 common frames omitted
20:48:32.455 [http-bio-8080-exec-34] DEBUG o.s.s.w.a.UsernamePasswordAuthenticationFilter - Authentication request failed: org.springframework.security.authentication.InternalAuthenticationServiceException: could not extract ResultSet; nested exception is org.hibernate.exception.JDBCConnectionException: could not extract ResultSet

Answer 1

Hibernate 需要知道方言，以便它可以连接到底层数据库。您需要为 MySQL 以及数据源定义将方言设置为 org.hibernate.dialect.MySQL5Dialect。

这是一个link这说明了为什么你需要方言。