java - 将对象保存到数据库时 hibernate 未知实体异常

Question

我一直在尝试使用 hibernate 来读取和写入 mysql 数据库，但是当我尝试 session.save() 将 Dept 对象保存到 dept mysql 表时，我不断收到未知实体错误。我一直在寻找解决方案，我尝试了很多不同的事情，包括注释我的代码、更改映射 xml 文件、hibernate 配置 xml 文件等。其他大多数遇到此错误的人都在使用 spring，但我不是，所以很多其他答案都不适用。我觉得我缺少了一些小东西。

启动器类:

final StandardServiceRegistry registry = new StandardServiceRegistryBuilder()
                .configure() // configures settings from hibernate.cfg.xml
                .build();
        try {
            SessionFactory sessionFactory = new MetadataSources( registry ).buildMetadata().buildSessionFactory();

            System.out.println("sessionfactory made, now creating session");
            Session session = sessionFactory.openSession();
            System.out.println("made session");
            session.beginTransaction();
            System.out.println("making first dept");
            session.save( new Dept(1, "Math",  "CORE"));
            session.save( new Dept(2, "Science", "CORE"));
            System.out.println("commiting transaction");
            session.getTransaction().commit();
            session.close();
            System.out.println("SUCCESS");
        }
        catch (Exception e) {
            // The registry would be destroyed by the SessionFactory, but we had trouble building the SessionFactory
            // so destroy it manually.
            e.printStackTrace();
            StandardServiceRegistryBuilder.destroy( registry );
            System.out.println("exception, destroyed registry");
        }

Java 部门:

package org.myschool.timeline.Timeline_App.domain;
// Generated Jan 16, 2016 1:48:30 AM by Hibernate Tools 4.3.1.Final

import java.util.HashSet;
import java.util.Set;

/**
 * Dept generated by hbm2java
 */
public class Dept implements java.io.Serializable {

    private int deptId;
    private String name;
    private String type;
    private Set<Course> courses = new HashSet<Course>(0);

    public Dept() {
    }

    public Dept(int deptId, String name, String type) {
        this.deptId = deptId;
        this.name = name;
        this.type = type;
    }

    public Dept(int deptId, String name, String type, Set<Course> courses) {
        this.deptId = deptId;
        this.name = name;
        this.type = type;
        this.courses = courses;
    }
    //Getters and Setters cut for brevity
}

hibernate .cfg.xml:

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>
        <property name="hibernate.bytecode.use_reflection_optimizer">false</property>
        <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="hibernate.connection.password">pass</property>
        <property name="hibernate.connection.url">jdbc:mysql://serverip</property>
        <property name="hibernate.connection.username">user</property>
        <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
        <property name="hibernate.search.autoregister_listeners">false</property>
        <property name="hibernate.validator.apply_to_ddl">false</property>
        <property name="current_session_context_class">thread</property>
        <property name="cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</property>
        <mapping resource="org/myschool/timeline/Timeline_App/domain/Admin.hbm.xml" />
        <mapping resource="org/myschool/timeline/Timeline_App/domain/Course.hbm.xml" />
        <mapping resource="org/myschool/timeline/Timeline_App/domain/Teacher.hbm.xml" />
        <mapping resource="org/myschool/timeline/Timeline_App/domain/Dept.hbm.xml" />
        <mapping resource="org/myschool/timeline/Timeline_App/domain/Student.hbm.xml" />
    </session-factory>
</hibernate-configuration>

和Dept.hbm.xml:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated Jan 16, 2016 1:52:21 AM by Hibernate Tools 3.5.0.Final -->
<hibernate-mapping>
    <class name="org.myschool.timeline.Timeline_App.domain.Dept" table="DEPT">
        <id name="deptId" type="int">
            <column name="DEPTID" />
            <generator class="assigned" />
        </id>
        <property name="name" type="java.lang.String">
            <column name="NAME" />
        </property>
        <property name="type" type="java.lang.String">
            <column name="TYPE" />
        </property>
        <set name="courses" table="COURSE" inverse="false" lazy="true">
            <key>
                <column name="DEPTID" />
            </key>
            <one-to-many class="org.myschool.timeline.Timeline_App.domain.Course" />
        </set>
    </class>
</hibernate-mapping>

这是我在启动时遇到的错误:

making first dept
org.hibernate.MappingException: Unknown entity: org.myschool.timeline.Timeline_App.domain.Dept
    at org.hibernate.internal.SessionFactoryImpl.getEntityPersister(SessionFactoryImpl.java:1096)
    at org.hibernate.internal.SessionImpl.getEntityPersister(SessionImpl.java:1479)
    at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:117)
    at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:209)
    at org.hibernate.event.internal.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:55)
    at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:194)
    at org.hibernate.event.internal.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:49)
    at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:90)
    at org.hibernate.internal.SessionImpl.fireSave(SessionImpl.java:715)
    at org.hibernate.internal.SessionImpl.save(SessionImpl.java:707)
    at org.hibernate.internal.SessionImpl.save(SessionImpl.java:702)
    at org.myschool.timeline.Timeline_App.App.main(App.java:120)
17/01/2016 02:10:41.860 [main] INFO o.h.e.j.c.i.DriverManagerConnectionProviderImpl - HHH000030: Cleaning up connection pool 
17/01/2016 02:10:41.862 [main] DEBUG o.h.b.r.i.BootstrapServiceRegistryImpl - Implicitly destroying Boot-strap registry on de-registration of all child ServiceRegistries
exception, destroyed registry

完整输出:

17/01/2016 02:10:35.891 [main] DEBUG org.jboss.logging - Logging Provider: org.jboss.logging.Slf4jLoggerProvider
17/01/2016 02:10:35.943 [main] DEBUG o.h.i.i.IntegratorServiceImpl - Adding Integrator [org.hibernate.cfg.beanvalidation.BeanValidationIntegrator].
17/01/2016 02:10:35.949 [main] DEBUG o.h.i.i.IntegratorServiceImpl - Adding Integrator [org.hibernate.secure.spi.JaccIntegrator].
17/01/2016 02:10:35.953 [main] DEBUG o.h.i.i.IntegratorServiceImpl - Adding Integrator [org.hibernate.cache.internal.CollectionCacheInvalidator].
17/01/2016 02:10:35.987 [main] DEBUG o.h.b.r.s.i.StrategySelectorImpl - Registering named strategy selector [org.hibernate.dialect.Dialect] : [MySQL5] -> [org.hibernate.dialect.MySQL5Dialect] (replacing [org.hibernate.dialect.MySQL5Dialect])
17/01/2016 02:10:35.987 [main] DEBUG o.h.b.r.s.i.StrategySelectorImpl - Registering named strategy selector [org.hibernate.dialect.Dialect] : [MySQL5InnoDB] -> [org.hibernate.dialect.MySQL5InnoDBDialect] (replacing [org.hibernate.dialect.MySQL5InnoDBDialect])
17/01/2016 02:10:36.082 [main] INFO  org.hibernate.Version - HHH000412: Hibernate Core {4.3.11.Final}
17/01/2016 02:10:36.086 [main] INFO  o.h.cfg.Environment - HHH000206: hibernate.properties not found
17/01/2016 02:10:36.089 [main] INFO  o.h.cfg.Environment - HHH000021: Bytecode provider name : javassist
17/01/2016 02:10:37.928 [main] DEBUG o.h.s.i.JaxbProcessor - cfg.xml document did not define namespaces; wrapping in custom event reader to introduce namespace information
17/01/2016 02:10:38.405 [main] DEBUG o.h.s.spi.ServiceBinding - Overriding existing service binding [org.hibernate.secure.spi.JaccService]
adds all the types
17/01/2016 02:10:38.651 [main] DEBUG o.h.i.f.i.DefaultIdentifierGeneratorFactory - Registering IdentifierGenerator strategy [uuid2] -> [org.hibernate.id.UUIDGenerator]
17/01/2016 02:10:38.652 [main] DEBUG o.h.i.f.i.DefaultIdentifierGeneratorFactory - Registering IdentifierGenerator strategy [guid] -> [org.hibernate.id.GUIDGenerator]
17/01/2016 02:10:38.654 [main] DEBUG o.h.i.f.i.DefaultIdentifierGeneratorFactory - Registering IdentifierGenerator strategy [uuid] -> [org.hibernate.id.UUIDHexGenerator]
17/01/2016 02:10:38.654 [main] DEBUG o.h.i.f.i.DefaultIdentifierGeneratorFactory - Registering IdentifierGenerator strategy [uuid.hex] -> [org.hibernate.id.UUIDHexGenerator]
17/01/2016 02:10:38.657 [main] DEBUG o.h.i.f.i.DefaultIdentifierGeneratorFactory - Registering IdentifierGenerator strategy [hilo] -> [org.hibernate.id.TableHiLoGenerator]
17/01/2016 02:10:38.658 [main] DEBUG o.h.i.f.i.DefaultIdentifierGeneratorFactory - Registering IdentifierGenerator strategy [assigned] -> [org.hibernate.id.Assigned]
17/01/2016 02:10:38.660 [main] DEBUG o.h.i.f.i.DefaultIdentifierGeneratorFactory - Registering IdentifierGenerator strategy [identity] -> [org.hibernate.id.IdentityGenerator]
17/01/2016 02:10:38.661 [main] DEBUG o.h.i.f.i.DefaultIdentifierGeneratorFactory - Registering IdentifierGenerator strategy [select] -> [org.hibernate.id.SelectGenerator]
17/01/2016 02:10:38.662 [main] DEBUG o.h.i.f.i.DefaultIdentifierGeneratorFactory - Registering IdentifierGenerator strategy [sequence] -> [org.hibernate.id.SequenceGenerator]
17/01/2016 02:10:38.663 [main] DEBUG o.h.i.f.i.DefaultIdentifierGeneratorFactory - Registering IdentifierGenerator strategy [seqhilo] -> [org.hibernate.id.SequenceHiLoGenerator]
17/01/2016 02:10:38.665 [main] DEBUG o.h.i.f.i.DefaultIdentifierGeneratorFactory - Registering IdentifierGenerator strategy [increment] -> [org.hibernate.id.IncrementGenerator]
17/01/2016 02:10:38.666 [main] DEBUG o.h.i.f.i.DefaultIdentifierGeneratorFactory - Registering IdentifierGenerator strategy [foreign] -> [org.hibernate.id.ForeignGenerator]
17/01/2016 02:10:38.667 [main] DEBUG o.h.i.f.i.DefaultIdentifierGeneratorFactory - Registering IdentifierGenerator strategy [sequence-identity] -> [org.hibernate.id.SequenceIdentityGenerator]
17/01/2016 02:10:38.668 [main] DEBUG o.h.i.f.i.DefaultIdentifierGeneratorFactory - Registering IdentifierGenerator strategy [enhanced-sequence] -> [org.hibernate.id.enhanced.SequenceStyleGenerator]
17/01/2016 02:10:38.670 [main] DEBUG o.h.i.f.i.DefaultIdentifierGeneratorFactory - Registering IdentifierGenerator strategy [enhanced-table] -> [org.hibernate.id.enhanced.TableGenerator]
17/01/2016 02:10:38.686 [main] WARN  o.h.e.j.c.i.DriverManagerConnectionProviderImpl - HHH000402: Using Hibernate built-in connection pool (not for production use!)
17/01/2016 02:10:38.700 [main] INFO  o.h.e.j.c.i.DriverManagerConnectionProviderImpl - HHH000401: using driver [com.mysql.jdbc.Driver] at URL [jdbc:mysql://67.190.147.230:3306/school]
17/01/2016 02:10:38.701 [main] INFO  o.h.e.j.c.i.DriverManagerConnectionProviderImpl - HHH000006: Autocommit mode: false
17/01/2016 02:10:38.704 [main] INFO  o.h.e.j.c.i.DriverManagerConnectionProviderImpl - HHH000115: Hibernate connection pool size: 20 (min=1)
17/01/2016 02:10:38.705 [main] DEBUG o.h.e.j.c.i.DriverManagerConnectionProviderImpl - Initializing Connection pool with 1 Connections
17/01/2016 02:10:40.892 [main] DEBUG o.h.e.j.i.JdbcServicesImpl - JDBC version : 4.0
17/01/2016 02:10:40.897 [main] DEBUG o.h.e.j.c.i.StandardRefCursorSupport - Unexpected error trying to gauge level of JDBC REF_CURSOR support : null
17/01/2016 02:10:40.963 [main] INFO  o.h.dialect.Dialect - HHH000400: Using dialect: org.hibernate.dialect.MySQLDialect
17/01/2016 02:10:41.268 [main] DEBUG o.h.i.SessionFactoryImpl - Building session factory
17/01/2016 02:10:41.275 [main] DEBUG o.h.e.t.j.p.i.JtaPlatformInitiator - No JtaPlatform was specified, checking resolver
17/01/2016 02:10:41.276 [main] DEBUG o.h.e.t.j.p.i.JtaPlatformResolverInitiator - No JtaPlatformResolver was specified, using default [org.hibernate.engine.transaction.jta.platform.internal.StandardJtaPlatformResolver]
17/01/2016 02:10:41.282 [main] DEBUG o.h.e.t.j.p.i.StandardJtaPlatformResolver - Could not resolve JtaPlatform, using default [org.hibernate.engine.transaction.jta.platform.internal.NoJtaPlatform]
17/01/2016 02:10:41.292 [main] DEBUG o.h.cfg.SettingsFactory - Automatic flush during beforeCompletion(): disabled
17/01/2016 02:10:41.292 [main] DEBUG o.h.cfg.SettingsFactory - Automatic session close at end of transaction: disabled
17/01/2016 02:10:41.293 [main] DEBUG o.h.cfg.SettingsFactory - JDBC batch size: 15
17/01/2016 02:10:41.293 [main] DEBUG o.h.cfg.SettingsFactory - JDBC batch updates for versioned data: disabled
17/01/2016 02:10:41.293 [main] DEBUG o.h.cfg.SettingsFactory - Scrollable result sets: enabled
7/01/2016 02:10:41.293 [main] DEBUG o.h.cfg.SettingsFactory - Wrap result sets: disabled
17/01/2016 02:10:41.293 [main] DEBUG o.h.cfg.SettingsFactory - JDBC3 getGeneratedKeys(): enabled
17/01/2016 02:10:41.294 [main] DEBUG o.h.cfg.SettingsFactory - multi-tenancy strategy : NONE
17/01/2016 02:10:41.294 [main] DEBUG o.h.cfg.SettingsFactory - Connection release mode: auto
17/01/2016 02:10:41.294 [main] INFO  o.h.e.t.i.TransactionFactoryInitiator - HHH000399: Using default transaction strategy (direct JDBC transactions)
17/01/2016 02:10:41.300 [main] DEBUG o.h.cfg.SettingsFactory - Using BatchFetchStyle : LEGACY
17/01/2016 02:10:41.300 [main] DEBUG o.h.cfg.SettingsFactory - Maximum outer join fetch depth: 2
17/01/2016 02:10:41.300 [main] DEBUG o.h.cfg.SettingsFactory - Default batch fetch size: 1
17/01/2016 02:10:41.301 [main] DEBUG o.h.cfg.SettingsFactory - Generate SQL with comments: disabled
17/01/2016 02:10:41.301 [main] DEBUG o.h.cfg.SettingsFactory - Order SQL updates by primary key: disabled
17/01/2016 02:10:41.301 [main] DEBUG o.h.cfg.SettingsFactory - Order SQL inserts for batching: disabled
17/01/2016 02:10:41.301 [main] DEBUG o.h.cfg.SettingsFactory - Default null ordering: none
17/01/2016 02:10:41.302 [main] DEBUG o.h.cfg.SettingsFactory - Query translator: org.hibernate.hql.internal.ast.ASTQueryTranslatorFactory
17/01/2016 02:10:41.306 [main] INFO  o.h.h.i.a.ASTQueryTranslatorFactory - HHH000397: Using ASTQueryTranslatorFactory
17/01/2016 02:10:41.307 [main] DEBUG o.h.cfg.SettingsFactory - Query language substitutions: {}
17/01/2016 02:10:41.307 [main] DEBUG o.h.cfg.SettingsFactory - JPA-QL strict compliance: disabled
17/01/2016 02:10:41.307 [main] DEBUG o.h.cfg.SettingsFactory - Second-level cache: enabled
17/01/2016 02:10:41.307 [main] DEBUG o.h.cfg.SettingsFactory - Query cache: disabled
17/01/2016 02:10:41.309 [main] DEBUG o.h.c.i.RegionFactoryInitiator - Cache region factory : org.hibernate.cache.internal.NoCachingRegionFactory
17/01/2016 02:10:41.314 [main] DEBUG o.h.cfg.SettingsFactory - Optimize cache for minimal puts: disabled
17/01/2016 02:10:41.314 [main] DEBUG o.h.cfg.SettingsFactory - Structured second-level cache entries: disabled
17/01/2016 02:10:41.314 [main] DEBUG o.h.cfg.SettingsFactory - Second-level cache direct-reference entries: disabled
17/01/2016 02:10:41.314 [main] DEBUG o.h.cfg.SettingsFactory - Automatic eviction of collection cache: disabled
17/01/2016 02:10:41.314 [main] DEBUG o.h.cfg.SettingsFactory - Statistics: disabled
17/01/2016 02:10:41.315 [main] DEBUG o.h.cfg.SettingsFactory - Deleted entity synthetic identifier rollback: disabled
17/01/2016 02:10:41.316 [main] DEBUG o.h.cfg.SettingsFactory - Default entity-mode: pojo
17/01/2016 02:10:41.317 [main] DEBUG o.h.cfg.SettingsFactory - Named query checking : enabled
17/01/2016 02:10:41.317 [main] DEBUG o.h.cfg.SettingsFactory - Check Nullability in Core (should be disabled when Bean Validation is on): enabled
17/01/2016 02:10:41.331 [main] DEBUG o.h.cfg.SettingsFactory - Allow initialization of lazy state outside session : : disabled
17/01/2016 02:10:41.332 [main] DEBUG o.h.cfg.SettingsFactory - JTA Track by Thread: enabled
17/01/2016 02:10:41.357 [main] DEBUG o.h.i.SessionFactoryImpl - Session factory constructed with filter configurations : {}
17/01/2016 02:10:41.384 [main] DEBUG o.h.s.spi.JaccIntegrator - Skipping JACC integration as it was not enabled
17/01/2016 02:10:41.592 [main] DEBUG o.h.i.SessionFactoryRegistry - Initializing SessionFactoryRegistry : org.hibernate.internal.SessionFactoryRegistry@36916eb0
17/01/2016 02:10:41.597 [main] DEBUG o.h.i.SessionFactoryRegistry - Registering SessionFactory: 6757530c-07f1-45bd-8c6f-a3a9697d6341 (<unnamed>)
17/01/2016 02:10:41.597 [main] DEBUG o.h.i.SessionFactoryRegistry - Not binding SessionFactory to JNDI, no JNDI name configured
17/01/2016 02:10:41.597 [main] DEBUG o.h.i.SessionFactoryImpl - Instantiated session factory
17/01/2016 02:10:41.598 [main] DEBUG o.h.i.NamedQueryRepository - Checking 0 named HQL queries
17/01/2016 02:10:41.598 [main] DEBUG o.h.i.NamedQueryRepository - Checking 0 named SQL queries
17/01/2016 02:10:41.610 [main] DEBUG o.h.s.i.StatisticsInitiator - Statistics initialized [enabled=false]
sessionfactory made, now creating session
made session
17/01/2016 02:10:41.739 [main] DEBUG o.h.e.t.s.AbstractTransactionImpl - begin
17/01/2016 02:10:41.740 [main] DEBUG o.h.e.j.i.LogicalConnectionImpl - Obtaining JDBC connection
17/01/2016 02:10:41.740 [main] DEBUG o.h.e.j.i.LogicalConnectionImpl - Obtained JDBC connection
17/01/2016 02:10:41.740 [main] DEBUG o.h.e.t.i.j.JdbcTransaction - initial autocommit status: false

我需要做什么来解决这个问题并能够将对象保存到数据库中？

Answer 1

已修复，我必须以不同的方式创建 session 工厂，就像这样

private static SessionFactory buildSessionFactory() {
    try{
        Configuration configuration = new Configuration();
        configuration.configure("hibernate.cfg.xml");
        StandardServiceRegistryBuilder ssrb = new StandardServiceRegistryBuilder().applySettings(configuration.getProperties());
        SessionFactory sess = configuration.buildSessionFactory(ssrb.build());
        return sess;
    } catch (Throwable ex) {
        System.err.println("SessionFactory creation failed." + ex);
        ex.printStackTrace();
        throw new ExceptionInInitializerError(ex);
    }
}

我不完全确定为什么会这样，但我猜它不是以另一种方式读取 hibernate.cfg.xml