Why does Hibernate detect null values when I am trying to add a new object? I have a Product class that has a field object Category. Category in Product is stored in the database as category_id. Here is my Product class.
@Entity
@Table(name = "PRODUCT")
public class Product implements java.io.Serializable {
/**
*
*/
private static final long serialVersionUID = 1L;
private long id;
private String upc;
private Category category;
private String name;
private String description;
private BigDecimal price;
public Product(){
}
public Product(String upc){
this.upc = upc;
}
public Product(String upc, String name, BigDecimal price){
this.upc = upc;
this.name = name;
this.price = price;
}
public Product(String upc, Category category, String name, String description, BigDecimal price) {
super();
this.upc = upc;
this.category = category;
this.name = name;
this.description = description;
this.price = price;
}
public void setId(long id) {
this.id = id;
}
@Id @GeneratedValue
@Column(name = "id")
public long getId() {
return id;
}
@Column(name = "upc", nullable = false)
public String getUpc() {
return upc;
}
public void setUpc(String upc) {
this.upc = upc;
}
@ManyToOne @NotNull
@JoinColumn(name = "category_id", referencedColumnName = "category_id")
public Category getCategory() {
return category;
}
public void setCategory(Category category) {
this.category = category;
}
@Column(name = "name")
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Column(name = "description")
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
@Column(name = "price")
public BigDecimal getPrice() {
return price;
}
public void setPrice(BigDecimal price) {
this.price = price;
}
}
And here is my Category class:
@Entity
@Table(name = "CATEGORY")
public class Category implements Serializable{
/**
*
*/
private static final long serialVersionUID = 1L;
private long id;
private String categoryId;
private String name;
private Set<Product> products;
public Category(){}
public Category(String categoryId, String name) {
super();
this.categoryId = categoryId;
this.name = name;
}
public void setId(long id) {
this.id = id;
}
@Id @GeneratedValue
@Column(name = "id")
public long getId() {
return id;
}
@Column(name = "category_id")
public String getCategoryId() {
return categoryId;
}
public void setCategoryId(String categoryId) {
this.categoryId = categoryId;
}
@Column(name = "name")
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@OneToMany
@JoinColumn(name = "category_id", insertable = false, updatable = false)
public Set<Product> getProducts() {
return products;
}
public void setProducts(Set<Product> products) {
this.products = products;
}
}
Now, when I am using the session.save(product) method, it gets a null value for the Category field but when using native sql in runs perfectly. I tried to print the category id and its there. Here is my code for add product:
@Override
public void addProduct(Product product) {
System.out.println(product.getCategory().getCategoryId());
Session session = sessionFactory.openSession();
Transaction transaction = null;
try {
transaction = session.beginTransaction();
// Query query = session.createSQLQuery(DAOQuery.HQL_ADD_PRODUCT).setParameter("upc", product.getUpc())
// .setParameter("category", product.getCategory().getCategoryId())
// .setParameter("name", product.getName()).setParameter("description", product.getDescription())
// .setParameter("price", product.getPrice());
//
// query.executeUpdate();
session.save(product);
transaction.commit();
} catch (HibernateException e) {
if (transaction != null)
transaction.rollback();
e.printStackTrace();
} finally {
session.close();
}
}
Here is the error:
WARN: SQL Error: 1048, SQLState: 23000
Oct 20, 2016 8:30:15 PM org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions
ERROR: Column 'category_id' cannot be null
org.hibernate.exception.ConstraintViolationException: could not execute statement
at org.hibernate.exception.internal.SQLStateConversionDelegate.convert(SQLStateConversionDelegate.java:112)
at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:42)
at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:111)
at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:97)
at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:207)
at org.hibernate.dialect.identity.GetGeneratedKeysDelegate.executeAndExtract(GetGeneratedKeysDelegate.java:57)
at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:42)
at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2840)
at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:3411)
at org.hibernate.action.internal.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:81)
at org.hibernate.engine.spi.ActionQueue.execute(ActionQueue.java:597)
at org.hibernate.engine.spi.ActionQueue.addResolvedEntityInsertAction(ActionQueue.java:232)
at org.hibernate.engine.spi.ActionQueue.addInsertAction(ActionQueue.java:213)
at org.hibernate.engine.spi.ActionQueue.addAction(ActionQueue.java:256)
at org.hibernate.event.internal.AbstractSaveEventListener.addInsertAction(AbstractSaveEventListener.java:318)
at org.hibernate.event.internal.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:275)
at org.hibernate.event.internal.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:182)
at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:113)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:192)
at org.hibernate.event.internal.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:38)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:177)
at org.hibernate.event.internal.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:32)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:73)
at org.hibernate.internal.SessionImpl.fireSave(SessionImpl.java:667)
at org.hibernate.internal.SessionImpl.save(SessionImpl.java:659)
at org.hibernate.internal.SessionImpl.save(SessionImpl.java:654)
at com.qbryx.dao.ProductDaoHQLImpl.addProduct(ProductDaoHQLImpl.java:138)
at com.qbryx.service.ManagerServiceImpl.addProduct(ManagerServiceImpl.java:24)
at com.qbryx.controller.ManagementController.createProduct(ManagementController.java:62)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:180)
at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:440)
at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:428)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:648)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
at org.springframework.orm.hibernate5.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:151)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:528)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1100)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:687)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1520)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1476)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Unknown Source)
Caused by: java.sql.SQLException: Column 'category_id' cannot be null
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2975)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1600)
at com.mysql.jdbc.ServerPreparedStatement.serverExecute(ServerPreparedStatement.java:1129)
at com.mysql.jdbc.ServerPreparedStatement.executeInternal(ServerPreparedStatement.java:681)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1368)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1283)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1268)
at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:204)
... 63 more
I cant seem to find what's wrong. I need help. Thanks.
答案 0 :(得分：3)
The error says that categoryId is null, while your database is configured to be not null.
You tagged id with @Id @GeneratedValue and Hibernate generate a new long value for that, but if you don't provide a value for categoryId it won't be generated.
You should either move the @Id @GeneratedValue to categoryId or provide a value when you build it.
Furthermore, I suggest you to review your design, because it's confusing to have both id and categoryId in your class; at the end of the day everybody will refer to the property id as "category id` and you won't know if they're referring to that id or to "categoryId".
答案 1 :(得分：0)
您未提供为类别生成Id的正确策略。
如果您的数据库使用序列，您可以将id映射为：
@GeneratedValue(strategy = GenerationType.IDENTITY)
如果不是
，那么创建生成策略@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "category_generator")
@SequenceGenerator(name="category_generator", sequenceName = "category_seq")