JPA @EmbeddedId没有生成序列

问题描述

我有一个表，该表具有由一个序列和两个外键组成的复合主键我可以保留我的实体类，但是它不是按照顺序生成的.具有由一个序列和两个外键组成的复合主键的表，在maven中的hbm2java提供了以下实体

I have a table which has composite primary key consisting one sequence and two foreign keysI am able to persist My entity class but it is not generating according to the sequence. The table which has composite primary key consisting one sequence and two foreign keys, hbm2java in maven gives following entities

这是主要实体

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;
 }

}

这是嵌入式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ID会自动生成...我只添加了

Here I am expecting the Id to be autogenerated...I have only added

@NaturalId

和

@GeneratedValue(strategy=GenerationType.SEQUENCE)

我也尝试过GenerationType.AUTO但没有用.请提出建议.

I have also tried with GenerationType.AUTObut did not work.Please suggest.

推荐答案

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

Just wanna to add my 2c. This works with composite and single primary keys. Prevent for creating sequences, instead, select max + 1 from the table.

Identifiable.java

Identifiable.java

package my.app.hibernate;

import java.io.Serializable;

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

CompositeKeyEntity.java

CompositeKeyEntity.java

 package my.app.hibernate;

 import java.io.Serializable;

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

SingleKeyEntity.java

SingleKeyEntity.java

package my.app.hibernate;

import java.io.Serializable;

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

AssignedIdentityGenerator.java

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

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(在SingleKeyEntity示例之后省略了Item.java)

CustomerItemsId.java (Item.java ommited as it follows SingleKeyEntity example)

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

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;
}

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