使用Hibernate+MySql+native SQL的BUG,以及解决办法

 

本来是mssql+hibernate+native SQL 应用的很和谐

但是到了把mssql换成mysql，就出了错(同样的数据结构和数据)。

查询方法是：

1. String sql =
2. "select id XXX_ID  from t_tab";
3. List<Map> list = session.createSQLQuery(sql)
4. .setResultTransformer(Transformers.ALIAS_TO_ENTITY_MAP)
5. .list();

错误信息：

1. org.hibernate.exception.SQLGrammarException: could not execute query
2. at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:90)
3. at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
4. at org.hibernate.loader.Loader.doList(Loader.java:2231)
5. at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2125)
6. at org.hibernate.loader.Loader.list(Loader.java:2120)
7. at org.hibernate.loader.custom.CustomLoader.list(CustomLoader.java:312)
8. at org.hibernate.impl.SessionImpl.listCustomQuery(SessionImpl.java:1722)
9. at org.hibernate.impl.AbstractSessionImpl.list(AbstractSessionImpl.java:165)
10. at org.hibernate.impl.SQLQueryImpl.list(SQLQueryImpl.java:175)
11. at com.exsun.common.dao.BasDaoImpl.findBySql(BasDaoImpl.java:173)
12. at com.exsun.arms.service.EmployeesalaryService.getList(EmployeesalaryService.java:32)
13. at com.exsun.arms.service.EmployeesalaryService$$FastClassByCGLIB$$2d81000f.invoke(<generated>)
14. at net.sf.cglib.proxy.MethodProxy.invoke(MethodProxy.java:149)
15. at org.springframework.aop.framework.Cglib2AopProxy$CglibMethodInvocation.invokeJoinpoint(Cglib2AopProxy.java:700)
16. at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:149)
17. at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:106)
18. at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
19. at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:89)
20. at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
21. at org.springframework.aop.framework.Cglib2AopProxy$DynamicAdvisedInterceptor.intercept(Cglib2AopProxy.java:635)
22. at com.exsun.arms.service.EmployeesalaryService$$EnhancerByCGLIB$$1e3e6d9f.getList(<generated>)
23. at com.exsun.arms.action.EmployeesalaryAction.getList(EmployeesalaryAction.java:110)
24. at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
25. at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
26. at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
27. at java.lang.reflect.Method.invoke(Method.java:597)
28. at org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:269)
29. at org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:170)
30. at org.springframework.web.struts.DelegatingActionProxy.execute(DelegatingActionProxy.java:110)
31. at org.apache.struts.chain.commands.servlet.ExecuteAction.execute(ExecuteAction.java:58)
32. at org.apache.struts.chain.commands.AbstractExecuteAction.execute(AbstractExecuteAction.java:67)
33. at org.apache.struts.chain.commands.ActionCommandBase.execute(ActionCommandBase.java:51)
34. at org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:191)
35. at org.apache.commons.chain.generic.LookupCommand.execute(LookupCommand.java:305)
36. at org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:191)
37. at org.apache.struts.chain.ComposableRequestProcessor.process(ComposableRequestProcessor.java:283)
38. at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
39. at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:449)
40. at javax.servlet.http.HttpServlet.service(HttpServlet.java:627)
41. at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
42. at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
43. at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
44. at org.springframework.orm.hibernate3.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:198)
45. at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
46. at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
47. at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
48. at com.exsun.common.util.MenuFilter.doFilter(MenuFilter.java:103)
49. at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
50. at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
51. at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:96)
52. at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
53. at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
54. at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
55. at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
56. at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
57. at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
58. at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
59. at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
60. at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)
61. at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:873)
62. at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
63. at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
64. at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
65. at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
66. at java.lang.Thread.run(Thread.java:619)
67. Caused by: java.sql.SQLException: Column 'id' not found.
68. at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1072)
69. at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:986)
70. at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:981)
71. at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:926)
72. at com.mysql.jdbc.ResultSetImpl.findColumn(ResultSetImpl.java:1144)
73. at com.mysql.jdbc.ResultSetImpl.getString(ResultSetImpl.java:5616)
74. at org.hibernate.type.StringType.get(StringType.java:41)
75. at org.hibernate.type.NullableType.nullSafeGet(NullableType.java:184)
76. at org.hibernate.type.NullableType.nullSafeGet(NullableType.java:210)
77. at org.hibernate.loader.custom.CustomLoader$ScalarResultColumnProcessor.extract(CustomLoader.java:497)
78. at org.hibernate.loader.custom.CustomLoader$ResultRowProcessor.buildResultRow(CustomLoader.java:443)
79. at org.hibernate.loader.custom.CustomLoader.getResultColumnOrRow(CustomLoader.java:340)
80. at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:629)
81. at org.hibernate.loader.Loader.doQuery(Loader.java:724)
82. at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:259)
83. at org.hibernate.loader.Loader.doList(Loader.java:2228)
84. ... 62 more

看到最后Caused by: java.sql.SQLException:

所以我试试用JDBC连接

1. public class TestMySqlJDBC {
2. public static void main(String[] args) throws Exception, IllegalAccessException, ClassNotFoundException {
3. Class.forName("com.mysql.jdbc.Driver").newInstance();
4. Connection con=java.sql.DriverManager.getConnection("jdbc:mysql://localhost:3306/arms?useUnicode=true&characterEncoding=utf8&","root","");
5. Statement stmt=con.createStatement();
6. ResultSet rs=stmt.executeQuery("select id XXX_ID,name  from t_tab");
7. while(rs.next())
8. {
9. System.out.printf("id:%s___name:%s/n",rs.getString("XXX_ID"),rs.getString("name"));
10. }
11. rs.close();
12. stmt.close();
13. con.close();
14. }
15. }

可以很正常的运行。

后来仔细又看了一下hibernate的执行错误

Caused by: java.sql.SQLException: Column 'id' not found.

是ID 找不到 不是XXX_ID 找不到。这意思貌似hibernate就没按别名alias 来取值

跟踪了一下hibernate

其中在Customer里发现的这一段

1. public class ScalarResultColumnProcessor implements ResultColumnProcessor {
2. private int position = -1;
3. private String alias;
4. private Type type;
5. public ScalarResultColumnProcessor(int position) {
6. this.position = position;
7. }
8. public ScalarResultColumnProcessor(String alias, Type type) {
9. this.alias = alias;
10. this.type = type;
11. }
12. //这个方法中的alias 为"id"而不是XXX_ID
13. public Object extract(
14. Object[] data,
15. ResultSet resultSet,
16. SessionImplementor session) throws SQLException, HibernateException {
17. return type.nullSafeGet( resultSet, alias, session, null );
18. }
19. ...........
20. ...........
21. ...........

hibernate是按照select id,name from tab来解释

而不是 select id XXX_ID , name from tab

这里跟到的数据果然是Hibernate把alias给忽略了。。。

-------------------------------------

继续跟踪hibernate代码.根据调用栈,单步跟踪很快找到

org.hibernate.loader.custom.CustomLoader$ScalarResultColumnProcessor 里面的

1. public void performDiscovery(Metadata metadata, List types, List aliases) throws SQLException {
2. if ( alias == null ) {
3. alias = metadata.getColumnName( position );
4. }
5. else if ( position < 0 ) {
6. position = metadata.resolveColumnPosition( alias );
7. }
8. if ( type == null ) {
9. type = metadata.getHibernateType( position );
10. }
11. types.add( type );
12. aliases.add( alias );
13. }

这里就是拼装将来要根据列名get出来的结果的地方

alias = metadata.getColumnName( position )

getColumnName 跟进去就是JDBC的实现.

跟踪可以看到.从这里get出来的alias不是真正的aliasName,而是originalColumnName原始列名.

后来试着修改了hibernate各种方言的设置：MySQLDialect,MySQL5Dialect,MySQL5InnoDBDialect等等还是不行。

我用JDBC试了下

mysql-connector-java-5.1.9-bin.jar

mysql-connector-java-5.1.10-bin.jar

mysql-connector-java-5.1.11-bin.jar

1. ResultSet rs=stmt.executeQuery(sql);
2. ResultSetMetaData rsmd = rs.getMetaData();
3. int columnCount = rsmd.getColumnCount();
4. List<String> columnName = new ArrayList();
5. for (int i = 1; i <= columnCount; i++) {
6. String tmp = rsmd.getColumnName(i) + "___" + rsmd.getColumnLabel(i);
7. System.out.println(tmp);
8. }

三个实现,结果都是一样的.

mysql的JDBC要获取alias只能用getColumnLable,不能用getColumnName

而Hibernate取字段名称的时候就只用 getColumnName.

解决办法有两个,一个是改hibernate,再不就得改mysql.

怕Hibernate对别的数据库实现有影响

所以就拿mysql的JDBC驱动开刀了.

把com.mysql.jdbc.ResultSetMetaData

中的

1. public String getColumnName(int column) throws SQLException {
2. if (this.useOldAliasBehavior) {
3. return getField(column).getName();
4. }
5. String name = getField(column).getNameNoAliases();
6. if (name != null && name.length() == 0) {
7. return getField(column).getName();
8. }
9. return name;
10. }

修改为:

1. public String getColumnName(int column) throws SQLException {
2. return getColumnLable(column);
3. }

然后把JDBC重新打包一下

再运行就OK了.