Hibernate 无法通过注解方式获取实体

Question

org.hibernate.MappingException: Unknown entity: com.me.pojo.Cat
at org.hibernate.internal.SessionFactoryImpl.getEntityPersister(SessionFactoryImpl.java:1096)
at org.hibernate.internal.SessionImpl.getEntityPersister(SessionImpl.java:1488)
at org.hibernate.engine.internal.ForeignKeys.isTransient(ForeignKeys.java:242)
at org.hibernate.event.internal.AbstractSaveEventListener.getEntityState(AbstractSaveEventListener.java:521)
at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:116)
at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:75)
at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:811)
at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:784)
at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:789)

hibernate.cfg.xml

oracle.jdbc.driver.OracleDriver
tiger
jdbc:oracle:thin:@localhost:1521:ORCL
scott
org.hibernate.dialect.Oracle10gDialect
true

sessionfactory获取方式：
Configuration configuration = new Configuration().configure();
ServiceRegistry serviceRegistry= new StandardServiceRegistryBuilder().applySettings(configuration.getProperties()).build();
sessionFactory = configuration.buildSessionFactory(serviceRegistry);

import java.math.BigDecimal;
import java.util.Date;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;

/**

• Cat generated by hbm2java
  */
  @Entity
  @Table(name = "CAT", schema = "SCOTT")
  public class Cat implements java.io.Serializable {

  private BigDecimal id;
  private String name;
  private String description;
  private Date createdate;
  private BigDecimal motherId;

  public Cat() {
  }

  public Cat(BigDecimal id) {
  this.id = id;
  }

  public Cat(BigDecimal id, String name, String description, Date createdate, BigDecimal motherId) {
  this.id = id;
  this.name = name;
  this.description = description;
  this.createdate = createdate;
  this.motherId = motherId;
  }

  @Id

  @Column(name = "ID", unique = true, nullable = false, precision = 22, scale = 0)
  public BigDecimal getId() {
  return this.id;
  }

  public void setId(BigDecimal id) {
  this.id = id;
  }

  @Column(name = "NAME", length = 32)
  public String getName() {
  return this.name;
  }

  public void setName(String name) {
  this.name = name;
  }

  @Column(name = "DESCRIPTION", length = 100)
  public String getDescription() {
  return this.description;
  }

  public void setDescription(String description) {
  this.description = description;
  }

  @Temporal(TemporalType.DATE)
  @Column(name = "CREATEDATE", length = 7)
  public Date getCreatedate() {
  return this.createdate;
  }

  public void setCreatedate(Date createdate) {
  this.createdate = createdate;
  }

  @Column(name = "MOTHER_ID", precision = 22, scale = 0)
  public BigDecimal getMotherId() {
  return this.motherId;
  }

  public void setMotherId(BigDecimal motherId) {
  this.motherId = motherId;
  }

}

我在网上查了很多都是说的注解包引用错了，但是我的注解包引用的都是javax.persistence.*;请各位大神指点

Answer 1

1,检查你的映射文件的名字是否和你的pojo（*.java）的名字是否相同。
2.映射文件的名字是*.hbm.xml而不是*.xml
3.你是否加载了你的映射文件。
加载的方法有两种
（1）在你的Hibernate.cfg.xml配置文件中加载映射文件
<?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">

…………
…………
<!-- 用于记载映射文件Student.hbm.xml-->



（2）在你的测试代码的加载映射文件
Configuration cfg = new Configuration();
cfg.configure();
cfg.addClass(*.class); 这里的*.class是你的映射文件的名字*.hbm.class中的*。。。
但是你要注意，用第二种方法加载的时候，你的*.hbm.class文件必须位于classpath下面。