通过 Hibernate 使用 MySQL：org.hibernate.exception.SQLGrammarException

Question

我正在使用 Hibernate 来访问我的 java 应用程序的 MySQL 数据库。我使用 this instructions 配置了 Hibernate。现在我想查询我的数据库；使用此代码：

java.util.List categList = null;
SessionFactory sessionFacoryt ;
sessionFacoryt = NewHibernateUtil.getSessionFactory();
org.hibernate.classic.Session hiberanateSession = sessionFacoryt.getCurrentSession();
String HQL = "select r from RssCategory r";
Transaction transaction = hiberanateSession.beginTransaction();                
org.hibernate.Query q = hiberanateSession.createQuery(HQL);

// here is the Exception cause line  
categList = q.list();

正如你所看到的，因为最后一行；我看到了这个异常：

Oct 23, 2011 3:20:25 PM org.hibernate.util.JDBCExceptionReporter
logExceptions WARNING: SQL Error: 1064, SQLState: 42000 Oct 23, 2011
3:20:25 PM org.hibernate.util.JDBCExceptionReporter logExceptions
SEVERE: You have an error in your SQL syntax; check the manual that
corresponds to your MySQL server version for the right syntax to use
near '-IPTV-EPG.rss_category rsscategor0_' at line 1
org.hibernate.exception.SQLGrammarException: could not execute query at
org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:67) at
org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
at org.hibernate.loader.Loader.doList(Loader.java:2223)     at
org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2104)  at
org.hibernate.loader.Loader.list(Loader.java:2099)  at
org.hibernate.hql.classic.QueryTranslatorImpl.list(QueryTranslatorImpl.java:912) at
org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:172) at
org.hibernate.impl.SessionImpl.list(SessionImpl.java:1121)  at
org.hibernate.impl.QueryImpl.list(QueryImpl.java:79)    at
RSS.connectHtmlandleRSS.addTODB(connectHtmlandleRSS.java:206)   at
RSS.connectHtmlandleRSS.access$000(connectHtmlandleRSS.java:37)     at
RSS.connectHtmlandleRSS$1.run(connectHtmlandleRSS.java:163) Caused by:
com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an
error in your SQL syntax; check the manual that corresponds to your
MySQL server version for the right syntax to use near
'-IPTV-EPG.rss_category rsscategor0_' at line 1     at
sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at
sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39) at
sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27) at
java.lang.reflect.Constructor.newInstance(Constructor.java:513) at
com.mysql.jdbc.Util.handleNewInstance(Util.java:409)    at
com.mysql.jdbc.Util.getInstance(Util.java:384)  at
com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1054)  at
com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3566)  at
com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3498)  at
com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1959)   at
com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2113)    at
com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2568)     at
com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2113) at
com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:2275) at
org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:186) at 
org.hibernate.loader.Loader.getResultSet(Loader.java:1787)  at
org.hibernate.loader.Loader.doQuery(Loader.java:674)    at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236) at
org.hibernate.loader.Loader.doList(Loader.java:2220)

谁能指导我这个异常的原因？ 谢谢。

这是为 RssCategory 生成的映射；这个类是为这个包sakila.entity生成的。

<hibernate-mapping>
    <class name="sakila.entity.RssCategory" table="rss_category" catalog="SAMIM-IPTV-EPG">
        <id name="catId" type="int">
            <column name="cat_id" />
            <generator class="assigned" />
        </id>
        <property name="catName" type="string">
            <column name="cat_name" length="45" not-null="true" unique="true" />
        </property>
        <set name="rssNewses" inverse="true" table="rss_to_cat">
            <key>
                <column name="cat_id" not-null="true" />
            </key>
            <many-to-many entity-name="sakila.entity.RssNews">
                <column name="rss_id" not-null="true" />
            </many-to-many>
        </set>
    </class> </hibernate-mapping>

这是为 rss_category 生成的 SQL 代码：

CREATE TABLE `rss_category` (
  `cat_id` int(11) NOT NULL,
  `cat_name` varchar(45) COLLATE utf8_unicode_ci NOT NULL,
  PRIMARY KEY (`cat_id`),
  UNIQUE KEY `cat_name_UNIQUE` (`cat_name`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

Hibernate 生成的 HQL 查询是：

Hibernate: select rsscategor0_.cat_id as cat1_4_, rsscategor0_.cat_name as cat2_4_ from SAMIM-IPTV-EPG.rss_category rsscategor0_

Answer 1

问题肯定是由目录名称中的破折号引起的。尝试将目录名称更改为其他名称，不要使用破折号。

Answer 2

我遇到了一些类似的问题，因为我没有使用正确的方言（MySQL 方言）。请尝试将 hibernate.dialect 配置为 org.hibernate.dialect.MySQL5Dialect。

Answer 3

使用以下 HQL，

String HQL = "from RssCategory"

如果您希望将所有列作为 Object[] 的列表（或部分项目列表），请使用以下内容，

String HQL = "select r.prop1, r.prop2 ... from RssCategory r"