JPA @EmbeddedId不生成序列

我有一张表，其中包含一个序列和两个外键的复合主键我可以坚持我的实体类，但它不是根据序列生成的。其具有由一个序列和两个外键，调用：hbm2java在行家复合主键表给出了以下实体JPA @EmbeddedId不生成序列

这里是主实体

 

package aop.web.teacher.rmodels; 

// Generated Dec 14, 2010 8:45:32 PM by Hibernate Tools 3.2.2.GA 

import java.util.Date; 
import javax.persistence.AttributeOverride; 
import javax.persistence.AttributeOverrides; 
import javax.persistence.Column; 
import javax.persistence.EmbeddedId; 
import javax.persistence.Entity; 
import javax.persistence.FetchType; 
import javax.persistence.JoinColumn; 
import javax.persistence.ManyToOne; 
import javax.persistence.Table; 
import javax.persistence.Temporal; 
import javax.persistence.TemporalType; 

/** 
* Schoolmaster generated by hbm2java 
*/ 
@Entity 
@Table(name = "schoolmaster", schema = "public") 
public class Schoolmaster implements java.io.Serializable { 

private SchoolmasterId id; 
     ... 


@EmbeddedId 
@AttributeOverrides({ 
    @AttributeOverride(name = "id", column = @Column(name = "id", nullable = false)), 
    @AttributeOverride(name = "districtId", column = @Column(name = "district_id", nullable = false)), 
    @AttributeOverride(name = "typeOfSchool", column = @Column(name = "type_of_school", nullable = false)) }) 
public SchoolmasterId getId() { 
    return this.id; 
} 

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

@ManyToOne(fetch = FetchType.LAZY) 
@JoinColumn(name = "type_of_school", nullable = false, insertable = false, updatable = false) 
public AopTeachersTypeMaster getAopTeachersTypeMaster() { 
    return this.aopTeachersTypeMaster; 
} 

public void setAopTeachersTypeMaster(
    AopTeachersTypeMaster aopTeachersTypeMaster) { 
    this.aopTeachersTypeMaster = aopTeachersTypeMaster; 
} 

@ManyToOne(fetch = FetchType.LAZY) 
@JoinColumn(name = "school_nature") 
public AopTeachersSchoolNatureMaster getAopTeachersSchoolNatureMaster() { 
    return this.aopTeachersSchoolNatureMaster; 
} 

public void setAopTeachersSchoolNatureMaster(
    AopTeachersSchoolNatureMaster aopTeachersSchoolNatureMaster) { 
    this.aopTeachersSchoolNatureMaster = aopTeachersSchoolNatureMaster; 
} 

@ManyToOne(fetch = FetchType.EAGER) 
@JoinColumn(name = "district_id", nullable = false, insertable = false, updatable = false) 
public AopTeachersDistrictMaster getAopTeachersDistrictMaster() { 
    return this.aopTeachersDistrictMaster; 
} 

public void setAopTeachersDistrictMaster(
    AopTeachersDistrictMaster aopTeachersDistrictMaster) { 
    this.aopTeachersDistrictMaster = aopTeachersDistrictMaster; 
} 

@Column(name = "school_name", length = 50) 
public String getSchoolName() { 
    return this.schoolName; 
} 

public void setSchoolName(String schoolName) { 
    this.schoolName = schoolName; 
} 

@Column(name = "school_address") 
public String getSchoolAddress() { 
    return this.schoolAddress; 
} 

public void setSchoolAddress(String schoolAddress) { 
    this.schoolAddress = schoolAddress; 
} 

@Column(name = "school_phone_number", length = 12) 
public String getSchoolPhoneNumber() { 
    return this.schoolPhoneNumber; 
} 

public void setSchoolPhoneNumber(String schoolPhoneNumber) { 
    this.schoolPhoneNumber = schoolPhoneNumber; 
} 

@Temporal(TemporalType.DATE) 
@Column(name = "establishment_date", length = 13) 
public Date getEstablishmentDate() { 
    return this.establishmentDate; 
} 

public void setEstablishmentDate(Date establishmentDate) { 
    this.establishmentDate = establishmentDate; 
} 

@Column(name = "school_no_of_teachers") 
public Integer getSchoolNoOfTeachers() { 
    return this.schoolNoOfTeachers; 
} 

public void setSchoolNoOfTeachers(Integer schoolNoOfTeachers) { 
    this.schoolNoOfTeachers = schoolNoOfTeachers; 
} 

@Column(name = "school_no_of_students") 
public Integer getSchoolNoOfStudents() { 
    return this.schoolNoOfStudents; 
} 

public void setSchoolNoOfStudents(Integer schoolNoOfStudents) { 
    this.schoolNoOfStudents = schoolNoOfStudents; 
} 

}

这里是嵌入PK类。

 

/** 
* SchoolmasterId generated by hbm2java 
*/ 
@Embeddable 
public class SchoolmasterId implements java.io.Serializable { 


    private long id; 
    private long districtId; 
    private long typeOfSchool; 

    public SchoolmasterId() { 
    } 

    public SchoolmasterId(long id, long districtId, long typeOfSchool) { 
     this.id = id; 
     this.districtId = districtId; 
     this.typeOfSchool = typeOfSchool; 
    } 


    @Column(name="id", nullable=false) 
    @GeneratedValue(strategy=GenerationType.SEQUENCE) 
    public long getId() { 
     return this.id; 
    } 

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

    @NaturalId 
    @Column(name="district_id", nullable=false) 
    public long getDistrictId() { 
     return this.districtId; 
    } 

    public void setDistrictId(long districtId) { 
     this.districtId = districtId; 
    } 
    @NaturalId 
    @Column(name="type_of_school", nullable=false) 
    public long getTypeOfSchool() { 
     return this.typeOfSchool; 
    } 

    public void setTypeOfSchool(long typeOfSchool) { 
     this.typeOfSchool = typeOfSchool; 
    } 


    public boolean equals(Object other) { 
     if ((this == other)) return true; 
    if ((other == null)) return false; 
    if (!(other instanceof SchoolmasterId)) return false; 
    SchoolmasterId castOther = (SchoolmasterId) other; 

    return (this.getId()==castOther.getId()) 
&& (this.getDistrictId()==castOther.getDistrictId()) 
&& (this.getTypeOfSchool()==castOther.getTypeOfSchool()); 
    } 

    public int hashCode() { 
     int result = 17; 

     result = 37 * result + (int) this.getId(); 
     result = 37 * result + (int) this.getDistrictId(); 
     result = 37 * result + (int) this.getTypeOfSchool(); 
     return result; 
    } 


}

在这里，我希望对ID进行自动生成...... 我只加

 

@NaturalId

和

 

@GeneratedValue(strategy=GenerationType.SEQUENCE)

我也试图与GenerationType.AUTO 但没有不行。请建议。

来源

2010-12-15 nightfly

我怀疑你还没有收到一个答案，因为它不能完成。我有一个类似的用例（三个中的一个主键字段是自动生成的（PostgreSQL中的bigserial）），并且发现@GeneratedValue只能与@Id一起使用。 – 2011-06-12 11:15:09

令人惊讶的是，由于我见过的帖子数量太多，所以无法完成。我将其归咎于不想提供某种常见用例的hibernate/jpa/eclipselink开发人员的顽固态度。其中一个'我们知道更好'的态度。 – BillR 2012-06-05 18:17:00

这个问题有一个解决方法。我面临同样的情况，有4个字段作为组合键，其中1个需要按顺序生成。我还没有创建嵌入类，只有1个@Id字段需要按顺序生成。其余的所有字段值都是简单的列，因为在数据库中实施了引用完整性，并且我正在检查代码中其余3个字段的值是否为空。

如果发生错误，事务将回滚。

来源

2011-08-23 14:20:20

只想添加我的2c。这适用于复合主键和单主键。防止创建序列，而是从表中选择max + 1。

Identifiable.java

package my.app.hibernate; 

import java.io.Serializable; 

public interface Identifiable<T extends Serializable> { 
    T getId(); 
}

CompositeKeyEntity.java

package my.app.hibernate; 

import java.io.Serializable; 

public interface CompositeKeyEntity<T extends Serializable> extends Identifiable<T> { 
}

SingleKeyEntity.java

package my.app.hibernate; 

import java.io.Serializable; 

public interface SingleKeyEntity<T extends Serializable> extends Identifiable<T> { 
}

AssignedIdentityGenerator.java

package my.app.hibernate; 

import java.io.Serializable; 
import java.lang.reflect.Field; 
import java.util.Arrays; 
import java.util.List; 

import org.hibernate.Criteria; 
import org.hibernate.criterion.Projections; 
import org.hibernate.criterion.Restrictions; 
import org.hibernate.engine.spi.SessionImplementor; 
import org.hibernate.id.IdentityGenerator; 
import org.hibernate.internal.CriteriaImpl; 
import org.slf4j.Logger; 
import org.slf4j.LoggerFactory; 
import org.springframework.security.util.FieldUtils; 

public class AssignedIdentityGenerator extends IdentityGenerator { 
    private static final String ID_FIELD_NAME = "id"; 
    private final Logger LOG = LoggerFactory.getLogger(this.getClass()); 
    private Field sequenceField; 
    private String entityClassName; 

    @Override 
    public Serializable generate(SessionImplementor session, Object obj) { 
     @SuppressWarnings("unchecked") 
     Identifiable<Serializable> identifiable = (Identifiable<Serializable>)obj; 

     entityClassName = obj.getClass().getName(); 
     Criteria criteria = new CriteriaImpl(entityClassName, session); 
     criteria.setReadOnly(true); 
     Object toSet = null; 

     if (identifiable instanceof CompositeKeyEntity) { 
      Serializable id = identifiable.getId(); 
      if (id != null) { 
       String embaddebleClassName = id.getClass().getName(); 
       buildCriteriaForEmbeddedId(id, embaddebleClassName, criteria); 
       toSet = id; 
      } 
     } else if (obj instanceof SingleKeyEntity) { 
      toSet = identifiable; 
      sequenceField = FieldUtils.getField(identifiable.getClass(), ID_FIELD_NAME); 
      buildCriteriaForSingleId(criteria); 
     } 

     Number one = castToSequenceNumberType(1L); 
     Number value = (Number) criteria.uniqueResult(); 

     if(value != null) { 
      value = castToSequenceNumberType(value.longValue() + one.longValue()); 

      setFieldValue(sequenceField, value, toSet); 
     } else { 
      value = one; 
      setFieldValue(sequenceField, value, toSet); 
     } 

     return identifiable.getId(); 
    } 

    private void buildCriteriaForSingleId(Criteria criteria) { 
     criteria.setProjection(Projections.max(ID_FIELD_NAME).as("seq")); 
    } 

    private void buildCriteriaForEmbeddedId(Serializable id, String embaddebleClassName, Criteria criteria) { 
     List<Field> fields = Arrays.asList(id.getClass().getDeclaredFields()); 

     class Utils { 
      Field field; 
      boolean numberFound = false; 
     } 
     final Utils utils = new Utils(); 

     for (Field field : fields) { 
      if ("serialVersionUID".equals(field.getName()) || "$jacocoData".equals(field.getName())) { 
       continue; 
      } 

      if (Number.class.isAssignableFrom(field.getType())) { 
       if (utils.numberFound) { 
        throw new IllegalArgumentException(
          embaddebleClassName + " has more then one sequence field: " + field.getName() + ", " 
            + utils.field.getName() + ",..."); 
       } 

       utils.numberFound = true; 
       utils.field = field; 
       sequenceField = field; 

       criteria.setProjection(Projections.max(ID_FIELD_NAME + "." + sequenceField.getName()).as("seq")); 
      } else { 
       criteria.add(Restrictions.eq(ID_FIELD_NAME + "." + field.getName(), getFieldValue(field, id))); 
      } 
     } 
    } 

    private Number castToSequenceNumberType(Number n) { 
     return (Number) sequenceField.getType().cast(n); 
    } 

    private void setFieldValue(Field field, Object value, Object to) { 
     try { 
      field.setAccessible(true); 
      field.set(to, value); 
     } catch (IllegalArgumentException | IllegalAccessException e) { 
      LOG.error(e.getMessage(), e); 
     } 
    } 

    private Object getFieldValue(Field field, Object from) { 
     try { 
      field.setAccessible(true); 
      return field.get(from); 
     } catch (IllegalArgumentException | IllegalAccessException e) { 
      LOG.error(e.getMessage(), e); 
     } 

     return null; 
    } 
}

Customer.java

package my.app.entities; 

import javax.persistence.Column; 
import javax.persistence.Entity; 
import javax.persistence.GeneratedValue; 
import javax.persistence.Id; 
import org.hibernate.annotations.GenericGenerator; 

import my.app.hibernate.SingleKeyEntity; 

@Entity(name = "whatever_entity_name") 
@GenericGenerator(name = "WHATEVER_NAMED_GENERATOR", strategy = "my.app.hibernate.AssignedIdentityGenerator") 
public class Customer implements SingleKeyEntity<Long> { 

    @Id 
    @GeneratedValue(generator = "WHATEVER_NAMED_GENERATOR") 
    private Long id; 
    @Column(nullable = false) 
    private String name; 
}

CustomerItemsId.java（Item.java中省略，因为它遵循SingleKeyEntity例子）

package my.app.entities; 

import javax.persistence.Embeddable; 
import javax.persistence.JoinColumn; 
import javax.persistence.ManyToOne; 

@Embeddable 
public class CustomerItemsId implements Serializable { 
    private static final long serialVersionUID = 1L; //generate one 

    @ManyToOne 
    @JoinColumn(name = "customer_id") 
    private Customer customer; 
    @ManyToOne 
    @JoinColumn(name = "item_id") 
    private Item item; 
    private Long seq; //name as you wish 
}

CustomerItems.java

package my.app.entities; 

import javax.persistence.Column; 
import javax.persistence.Entity; 
import javax.persistence.GeneratedValue; 
import javax.persistence.Id; 
import org.hibernate.annotations.GenericGenerator; 

import my.app.hibernate.CompositeKeyEntity; 

@Entity(name = "whatever_entity_name") 
@GenericGenerator(name = "WHATEVER_NAMED_GENERATOR", strategy = "my.app.hibernate.AssignedIdentityGenerator") 
public class CustomerItems implements CompositeKeyEntity<CustomerItemsId> { 

    @GeneratedValue(generator = "WHATEVER_NAMED_GENERATOR") 
    private CustomerItems id; 
    @Column(nullable = false) 
    private String randomColumn1; 
    @Column(nullable = false) 
    private String randomColumn2; 
}

来源

2018-02-01 13:46:52

JPA @EmbeddedId不生成序列

回答

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