亲爱的开发者。列不能为null无法插入
我想问你一个问题，我觉得很难为我解决，只是因为我不知道基本上为什么要回答， 我的意思是？让我们来看看。 JBoss文档中的关联没有得到全面的答案：为什么我应该使用JoinTable而不是外键，并且我不完全了解映射的工作原理， 这是什么意思？我知道什么是ManyToMany或ManyToOne等的关联，以及它们的目的是什么，但它们是如何工作的并且彼此协作不需要关于双向或单向或joinTable或关联的答案，我想有链接在哪里可以找到我的两个问题充分信息：
1）为什么我要使用JoinTable而不是外键 ????
2）实体如何工作并彼此协作（没有解释什么是manyToMany等等协会和双向或单向协会）???
所以，我有一段代码，我坚持，因为误会，我只是想将数据插入我MYSQL数据库：Name_INSTITUTION和TYPE_NAME（机构类型）：*
我的实体类：
@Entity @Table(name="INSTITUTION") public class Institution implements Serializable{ private static final long serialVersionUID = -7636394097858726922L; private int Id; @Id @GeneratedValue(strategy=IDENTITY) @Column(name="ID") public int getId() { return Id; } public void setId(int id) { Id = id; } private int Version; @javax.persistence.Version @Column(name="VERSION") public int getVersion() { return Version; } public void setVersion(int version) { Version = version; } private String Name_Institution; @Column(name="NAME_INSTITUTION") public String getName_Institution() { return Name_Institution; } public void setName_Institution(String name_Institution) { Name_Institution = name_Institution; } private Type type_inInstitution; @ManyToOne @Cascade(org.hibernate.annotations.CascadeType.ALL) @JoinTable(name="TYPE_INSTITUTION", [email protected](name="INSTITUTION_ID"), [email protected](name="TYPE_ID")) public Type getType_inInstitution() { return type_inInstitution; } public void setType_inInstitution(Type type_inInstitution) { this.type_inInstitution = type_inInstitution; }}
我的第二个实体类：
@Entity @Table(name="TYPE") public class Type implements Serializable { private static final long serialVersionUID = -4246217431412815552L; private String type; public Type(){} public Type(String type) { this.type = type; } private int Type_Id; @Id @GeneratedValue(strategy=IDENTITY) @Column(name="ID") public int getType_Id() { return Type_Id; } public void setType_Id(int type_Id) { Type_Id = type_Id; } private String Type_Name; @Column(name="TYPE_NAME") public String getType_Name() { return Type_Name; } public void setType_Name(String type_Name) { Type_Name = type_Name; } private int Version; @Version @Column(name="VERSION") public int getVersion() { return Version; } public void setVersion(int version) { Version = version; } private Set<Institution> set_Institution_inType = new HashSet<Institution>(); @OneToMany @JoinTable(name="TYPE_INSTITUTION", [email protected](name="TYPE_ID"), [email protected](name="INSTITUTION_ID")) public Set<Institution> getSet_Institution_inType() { return set_Institution_inType; } public void setSet_Institution_inType(Set<Institution> set_Institution_inType) { this.set_Institution_inType = set_Institution_inType; } public void addType(Institution institution) { institution.setType_inInstitution(this); getSet_Institution_inType().add(institution); }}
在DAO类：
@Repository("daoInsertDataInterface") @Transactional public class InsertDataService implements DaoInsertDataInterface{ private org.apache.commons.logging.Log log= LogFactory.getLog(InsertDataService.class); private SessionFactory sessionFactory; public SessionFactory getSessionFactory() { return sessionFactory; } @Resource(name="sessionFactory") public void setSessionFactory(SessionFactory sessionFactory) { this.sessionFactory = sessionFactory; } @Override public Institution insertData(Institution institution) { sessionFactory.getCurrentSession().saveOrUpdate(institution); log.info(institution.getId()); return institution; }}
我metada配置：
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"> <property name="driverClassName"><value>${jdbc.driverClassName}</value></property> <property name="url"><value>${jdbc.connectionValues}</value></property> <property name="username"><value>${jdbc.userName}</value></property> <property name="password"><value>${jdbc.password}</value></property> </bean> <bean id="transactionManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager"> <property name="sessionFactory" ref ="sessionFactory"/> </bean> <context:property-placeholder location="connection.properties"/> <tx:annotation-driven transaction-manager="transactionManager"/> <context:component-scan base-package="edu.demidov.dom, edu.demidov.dao" /> <context:annotation-config /> <bean id="sessionFactory" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean"> <property name="dataSource" ref ="dataSource"/> <property name="packagesToScan" value="edu.demidov.dom"/> <property name="hibernateProperties"> <props> <prop key="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</prop> <prop key="hibernate.max_fetch_depth">3</prop> <prop key="hibernate.jdbc.fetch_size">50</prop> <prop key="hibernate.jdbc.batch_size">10</prop> <prop key="hibernate.show_sql">true</prop> </props> </property> </bean>和错误：
INFO : org.springframework.beans.factory.xml.XmlBeanDefinitionReader - Loading XML bean definitions from class path resource [app-context.xml] INFO : org.springframework.context.annotation.ClassPathBeanDefinitionScanner - JSR-330 'javax.inject.Named' annotation found and supported for component scanning INFO : org.springframework.context.support.GenericXmlApplicationContext - Refreshing o[email protected]c93274: startup date [Thu May 09 11:38:23 EDT 2013]; root of context hierarchy INFO : org.springframework.beans.factory.config.PropertyPlaceholderConfigurer - Loading properties file from class path resource [connection.properties] INFO : org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor - JSR-330 'javax.inject.Inject' annotation found and supported for autowiring INFO : org.springframework.beans.factory.support.DefaultListableBeanFactory - Pre-instantiating singletons in org.s[email protected]1b9c2f0: defining beans [dataSource,transactionManager,org.springframework.beans.factory.config.PropertyPlaceholderConfigurer#0,org.springframework.aop.config.internalAutoProxyCreator,org.springframework.transaction.annotation.AnnotationTransactionAttributeSource#0,org.springframework.transaction.interceptor.TransactionInterceptor#0,org.springframework.transaction.config.internalTransactionAdvisor,daoInsertDataInterface,org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalRequiredAnnotationProcessor,org.springframework.context.annotation.internalCommonAnnotationProcessor,org.springframework.context.annotation.internalPersistenceAnnotationProcessor,sessionFactory,org.springframework.context.annotation.ConfigurationClassPostProcessor.importAwareProcessor];
root of factory hierarchy Hibernate: insert into TYPE (TYPE_NAME, VERSION) values (?, ?) WARN : org.hibernate.util.JDBCExceptionReporter - SQL Error: 1048, SQLState: 23000 ERROR: org.hibernate.util.JDBCExceptionReporter - Column 'TYPE_NAME' cannot be null Exception in thread "main" org.hibernate.exception.ConstraintViolationException: could not insert: [edu.demidov.dom.Type] at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:96) at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66) at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:64) at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2327) at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2834) at org.hibernate.action.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:71) at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:273) at org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:320) at org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:203) at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:129) at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:210) at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:195) at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.performSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:117) at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:93) at org.hibernate.impl.SessionImpl.fireSaveOrUpdate(SessionImpl.java:685) at org.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:677) at org.hibernate.engine.CascadingAction$5.cascade(CascadingAction.java:252) at org.hibernate.engine.Cascade.cascadeToOne(Cascade.java:392) at org.hibernate.engine.Cascade.cascadeAssociation(Cascade.java:335) at org.hibernate.engine.Cascade.cascadeProperty(Cascade.java:204) at org.hibernate.engine.Cascade.cascade(Cascade.java:161) at org.hibernate.event.def.AbstractSaveEventListener.cascadeBeforeSave(AbstractSaveEventListener.java:450) at org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:282) at org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:203) at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:129) at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:210) at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:195) at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.performSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:117) at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:93) at org.hibernate.impl.SessionImpl.fireSaveOrUpdate(SessionImpl.java:685) at org.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:677) at org.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:673) at edu.demidov.dao.InsertDataService.insertData(InsertDataService.java:32) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:601) at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317) at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150) at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:96) at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:260) at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:94) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204) at $Proxy22.insertData(Unknown Source) at edu.demidov.dao.AppTEst.main(AppTEst.java:22) Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Column 'TYPE_NAME' cannot be null at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:525) at com.mysql.jdbc.Util.handleNewInstance(Util.java:411) at com.mysql.jdbc.Util.getInstance(Util.java:386) at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1041) at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4120) at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4052) at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2503) at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2664) at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2815) at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2155) at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2458) at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2375) at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2359) at org.hibernate.id.IdentityGenerator$GetGeneratedKeysDelegate.executeAndExtract(IdentityGenerator.java:94) at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:57) ... 44 more SS
谢谢你，伙计们。
+1为非常详细的问题。 – Jops 2013-05-09 15:26:04