Spring和Tomcat：未設置'hibernate.dialect'時對DialectResolutionInfo的訪問不能為空

Question

我有一個使用Spring Repository框架和MySQL數據庫的應用程序。 我目前將其部署在Tomcat 7上。

部署並嘗試登錄應用程序（對數據庫的首次調用）后，我將收到以下異常：

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

我已在數據庫上啟用查詢日志記錄，並且可以確認正在對數據庫查詢用戶對象。 但是，在登錄頁面本身上，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

為了使事情更加混亂，只有當我嘗試在遠程服務器上進行部署時，才會發生這種情況。 當我啟動MySQL的本地實例並在localhost上運行Tomcat的實例時，一切都會按預期進行。

以下是我的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>

有誰知道會導致問題的原因嗎？ Tomcat是否需要我不知道或忘記的配置？

謝謝你的幫助。

===更新1 ====

指定方言后，我將收到以下堆棧跟蹤：

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，以便它可以連接到基礎數據庫。 您需要將方言和數據源定義一起設置為MySQL的org.hibernate.dialect.MySQL5Dialect 。

這是一個說明為什么需要方言的鏈接 。

Answer 2

通過執行@Soheil的答案（在此處找到）中列出的步驟，我能夠解決此問題：

使用JDBC和MySQL解決“通信鏈接失敗”

原來，我所需要的只是按照@Dhanush Gopinath的建議添加休眠方言，並將以下內容添加到my.cnf文件中：

interactive_timeout=180
wait_timeout=180
connect_timeout=180
max_connect_errors=9999
skip-name-resolve