我是Hibernate的新手。
我正在尝试使用Hibernate创建在线用户调查，使用Oracle 10g数据库连接。在解决了一系列问题之后，我一直坚持这个问题：
HTTP状态500 - org.hibernate.hql.internal.ast.QuerySyntaxException：未映射用户[从用户用户中选择max（users.id）]
这是UserDAO.java
public class UserDAO {
Session session = HibernateUtil.getSessionFactory().openSession();
public void save(User user){
session.beginTransaction();
session.save(user);
session.getTransaction().commit();
session.close();
}
public Integer getId (){
String hql = "select max(users.id) from User users";
Query query = session.createQuery(hql);
List<Integer> results = query.list();
Integer userId = 1;
if (results.get(0) != null ) {
userId = results.get(0) + 1;
}
return userId;
}
}
这是User.java：
@Entity
@Table(name="User")
public class User {
@Column(name="firstname")
private String firstname;
@Column(name="lastname")
private String lastname;
@Column(name="address")
private String address;
@Column(name="city")
private String city;
@Column(name="state")
private String state;
@Column(name="zip")
private String zip;
@Column(name="phone")
private String phone;
@Id
@Column(name="email")
private String email;
@Column(name="date")
private Date todayDate;
@Column(name="semdate")
private Date semDate;
// ...
}
这是HibernateUtil.java：
public class HibernateUtil {
private static SessionFactory sessionFactory ;
static {
Configuration configuration = new Configuration().configure();
StandardServiceRegistryBuilder builder = new StandardServiceRegistryBuilder()
.applySettings(configuration.getProperties());
sessionFactory = configuration.buildSessionFactory(builder.build());
}
public static SessionFactory getSessionFactory() {
return sessionFactory;
}
}
这是hibernate.cfg.xml：
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
<property name="hibernate.connection.url">jdbc:oracle:thin:@apollo.vse.gmu.edu:1521:ite10g</property>
<property name="hibernate.connection.username">name</property>
<property name="hibernate.connection.password">password</property>
<property name="hibernate.dialect">org.hibernate.dialect.Oracle10gDialect</property>
<property name="hibernate.default_schema">name</property>
<property name="show_sql">true</property>
</session-factory>
</hibernate-configuration>
编辑：
我做了这里很棒的人提出的建议，即将映射类添加到xml文件中。这确实消除了原始错误。但现在，我面临一些其他错误： HTTP状态500 - org.hibernate.exception.GenericJDBCException：无法提取ResultSet
完整的堆栈跟踪在这里：
type Exception report
message org.hibernate.exception.GenericJDBCException: could not extract ResultSet
description The server encountered an internal error that prevented it from fulfilling this request.
exception
javax.servlet.ServletException: org.hibernate.exception.GenericJDBCException: could not extract ResultSet
javax.faces.webapp.FacesServlet.service(FacesServlet.java:659)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
root cause
javax.faces.el.EvaluationException: org.hibernate.exception.GenericJDBCException: could not extract ResultSet
javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:101)
com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102)
javax.faces.component.UICommand.broadcast(UICommand.java:315)
javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:790)
javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1282)
com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:198)
javax.faces.webapp.FacesServlet.service(FacesServlet.java:646)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
root cause
org.hibernate.exception.GenericJDBCException: could not extract ResultSet
org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:54)
org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:126)
org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:112)
org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.extract(ResultSetReturnImpl.java:89)
org.hibernate.loader.Loader.getResultSet(Loader.java:2065)
org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1862)
org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1838)
org.hibernate.loader.Loader.doQuery(Loader.java:909)
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:354)
org.hibernate.loader.Loader.doList(Loader.java:2553)
org.hibernate.loader.Loader.doList(Loader.java:2539)
org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2369)
org.hibernate.loader.Loader.list(Loader.java:2364)
org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:496)
org.hibernate.hql.internal.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:387)
org.hibernate.engine.query.spi.HQLQueryPlan.performList(HQLQueryPlan.java:231)
org.hibernate.internal.SessionImpl.list(SessionImpl.java:1264)
org.hibernate.internal.QueryImpl.list(QueryImpl.java:103)
com.pratikshinde.swe645.UserDAO.getId(UserDAO.java:18)
com.pratikshinde.swe645.StudentService.saveUser(StudentService.java:361)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:497)
org.apache.el.parser.AstValue.invoke(AstValue.java:247)
org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:267)
com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:87)
com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102)
javax.faces.component.UICommand.broadcast(UICommand.java:315)
javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:790)
javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1282)
com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:198)
javax.faces.webapp.FacesServlet.service(FacesServlet.java:646)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
root cause
java.sql.SQLException: Io exception: Size Data Unit (SDU) mismatch
oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:112)
oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:146)
oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:256)
oracle.jdbc.driver.T4CPreparedStatement.executeForDescribe(T4CPreparedStatement.java:828)
oracle.jdbc.driver.OracleStatement.executeMaybeDescribe(OracleStatement.java:1050)
oracle.jdbc.driver.T4CPreparedStatement.executeMaybeDescribe(T4CPreparedStatement.java:853)
oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1155)
oracle.jdbc.driver.OraclePreparedStatement.executeInternal(OraclePreparedStatement.java:3414)
oracle.jdbc.driver.OraclePreparedStatement.executeQuery(OraclePreparedStatement.java:3459)
org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.extract(ResultSetReturnImpl.java:80)
org.hibernate.loader.Loader.getResultSet(Loader.java:2065)
org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1862)
org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1838)
org.hibernate.loader.Loader.doQuery(Loader.java:909)
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:354)
org.hibernate.loader.Loader.doList(Loader.java:2553)
org.hibernate.loader.Loader.doList(Loader.java:2539)
org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2369)
org.hibernate.loader.Loader.list(Loader.java:2364)
org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:496)
org.hibernate.hql.internal.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:387)
org.hibernate.engine.query.spi.HQLQueryPlan.performList(HQLQueryPlan.java:231)
org.hibernate.internal.SessionImpl.list(SessionImpl.java:1264)
org.hibernate.internal.QueryImpl.list(QueryImpl.java:103)
com.pratikshinde.swe645.UserDAO.getId(UserDAO.java:18)
com.pratikshinde.swe645.StudentService.saveUser(StudentService.java:361)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:497)
org.apache.el.parser.AstValue.invoke(AstValue.java:247)
org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:267)
com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:87)
com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102)
javax.faces.component.UICommand.broadcast(UICommand.java:315)
javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:790)
javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1282)
com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:198)
javax.faces.webapp.FacesServlet.service(FacesServlet.java:646)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
请再帮忙一下！万分感谢！
答案 0 :(得分：1)
在<session-factory> </session-factory>
hibernate.cfg.xml之间添加此内容
<mapping class ="com.demo.User"/>
你错过了映射实体类
答案 1 :(得分：1)
您需要添加@kakashiHatake建议
<mapping class ="com.demo.User"/>
如果您使用Hibernate 5，则需要以这种方式配置会话工厂
sessionFactory = new Configuration().configure().buildSessionFactory();
答案 2 :(得分：0)
更改行：
Configuration configuration = new Configuration().configure();
到：
Configuration configuration = new Configuration()
.addPackage("com.demo")
.addAnnotatedClass(User.class)
// add all other classes you want
.configure();
编辑：请删除托管bean @Entity上的StudentService