休眠异常：表未映射

Question

我想通过休眠连接到Postgres，但是我得到异常表未映射。这里是代码：

的hibernate.cfg.xml

<!DOCTYPE hibernate-configuration SYSTEM 
    "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"> 
<hibernate-configuration> 
<session-factory> 
    <property name="hibernate.dialect">org.hibernate.dialect.PostgreSQL94Dialect</property> 
    <property name="hibernate.connection.driver_class">org.postgresql.Driver</property> 
    <property name="hibernate.connection.username">username</property> 
    <property name="hibernate.connection.password">passwrd</property> 
    <property name="hibernate.connection.url">jdbc:postgresql://localhost:5432/dbname</property> 
    <property name="hibernate.hbm2ddl.auto">create</property> 
    <property name="connection.pool_size">1</property> 
    <property name="show_sql">true</property> 
    <mapping class="backend.hibernate.models.UsersEntity"/> 
</session-factory> 

UsersEntity：

@Entity 
@Table(name = "Users") 
@Getter 
@Setter 
public class UsersEntity { 
@Id 
@Column(name = "id") 
@GeneratedValue 
private int id; 
@Column(name = "login") 
private String login; 
@Column(name = "password") 
private String password; 
@Column(name = "email") 
private String email; 

} 

POM：

<properties> 
    <hibernate.version>5.0.3.Final</hibernate.version> 
    <postgresql.version>9.4-1200-jdbc4</postgresql.version> 
</properties> 

<dependencies> 
    <dependency> 
     <groupId>org.hibernate</groupId> 
     <artifactId>hibernate-entitymanager</artifactId> 
     <version>${hibernate.version}</version> 
    </dependency> 

    <!-- The tutorials use the PostgreSQL 9.3.5 database --> 
    <dependency> 
     <groupId>org.postgresql</groupId> 
     <artifactId>postgresql</artifactId> 
     <version>${postgresql.version}</version> 
    </dependency> 

    <dependency> 
     <groupId>junit</groupId> 
     <artifactId>junit</artifactId> 
     <version>3.8.1</version> 
     <scope>test</scope> 
    </dependency> 
</dependencies> 

错误：

Exception in thread "main" org.hibernate.hql.internal.ast.QuerySyntaxException: UsersModel is not mapped [select login from UsersModel] 
at org.hibernate.hql.internal.ast.QuerySyntaxException.generateQueryException(QuerySyntaxException.java:79) 
at org.hibernate.QueryException.wrapWithQueryString(QueryException.java:103) 
at org.hibernate.hql.internal.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:218) 
at org.hibernate.hql.internal.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:142) 
at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:115) 
at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:76) 
at org.hibernate.engine.query.spi.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:150) 
at org.hibernate.internal.AbstractSessionImpl.getHQLQueryPlan(AbstractSessionImpl.java:298) 
at org.hibernate.internal.AbstractSessionImpl.createQuery(AbstractSessionImpl.java:236) 
at org.hibernate.internal.SessionImpl.createQuery(SessionImpl.java:1836) 
at Fronted.Main.main(Main.java:23) 
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) 
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
at java.lang.reflect.Method.invoke(Method.java:497) 
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:140) 
Caused by: org.hibernate.hql.internal.ast.QuerySyntaxException: UsersModel is not mapped 
at org.hibernate.hql.internal.ast.util.SessionFactoryHelper.requireClassPersister(SessionFactoryHelper.java:171) 
at org.hibernate.hql.internal.ast.tree.FromElementFactory.addFromElement(FromElementFactory.java:91) 
at org.hibernate.hql.internal.ast.tree.FromClause.addFromElement(FromClause.java:76) 
at org.hibernate.hql.internal.ast.HqlSqlWalker.createFromElement(HqlSqlWalker.java:321) 
at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.fromElement(HqlSqlBaseWalker.java:3678) 
at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.fromElementList(HqlSqlBaseWalker.java:3567) 
at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.fromClause(HqlSqlBaseWalker.java:708) 
at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.query(HqlSqlBaseWalker.java:564) 
at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.selectStatement(HqlSqlBaseWalker.java:301) 
at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.statement(HqlSqlBaseWalker.java:249) 
at org.hibernate.hql.internal.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:262) 
at org.hibernate.hql.internal.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:190) 
... 13 more 

主：

public class Main { 
public static void main(String[] args) { 
    Configuration configuration = new Configuration().configure(); 
    StandardServiceRegistryBuilder builder = new StandardServiceRegistryBuilder().applySettings(configuration 
      .getProperties()); 
    SessionFactory sessionFactory = configuration.buildSessionFactory(builder.build()); 
    Session session = sessionFactory.openSession(); 
    session.beginTransaction(); 
    List<UsersModel> list = session.createQuery("from UsersEntity").list(); 
    session.close(); 
    System.out.println(list); 
} 
} 

在我的数据库我有表名为 “用户” 的列像UsersEntity注释。我认为，该映射是正确完成的，但我仍然得到相同的错误。感谢您的帮助

Answer 1

错误很明显“UsersModel未映射”。这意味着您正尝试在查询中使用您尚未完成任何映射的类。

您所查询的UsersModel有以下几点：

List<UsersModel> list = session.createQuery("select login from UsersModel").list(); 

但映射到用户表的实体类是UsersEntity：

@Entity 
@Table(name = "Users") 
public class UsersEntity 

你应该做以下查询：

List<UsersEntity> list = session.createQuery("select login from UsersEntity").list(); 
// Map from UsersEntity to UsersModel if needed 

Answer 2

也许进入hibernate.cfg.xml中，你映射的是错误的班级名称。

在你的XML：

<mapping class="backend.hibernate.models.UsersModel"/> 

在你的Java类：

public class UsersEntity 

试图改变你的XML是这样的：

<mapping class="backend.hibernate.models.UsersEntity"/> 

Answer 3

当您使用实体名称为

UsersEntity 

所以请在hibernate.cfg中更改。XML从

<mapping class="backend.hibernate.models.UsersModel"/> 

到

<mapping class="backend.hibernate.models.UsersEntity"/> 

和变化在主：从

List<UsersModel> list = session.createQuery("select login from UsersModel").list(); 

到

List<UsersEntity> list = session.createQuery("select login from UsersEntity").list(); 

Answer 4

它可以通过编程方式添加，以及：

Configuration configuration = new Configuration(); 
configuration.configure("hibernate-local-query-test.cfg.xml"); 
configuration.addAnnotatedClass(ClassName.class);