JPA @EmbeddedId 不生成序列

Question

我有一个表，其中包含一个序列和两个外键的复合主键
我能够持久化我的实体类，但它没有按照顺序生成。由一个序列和两个外键组成的复合主键的表，maven中的hbm2java给出了以下实体

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，我希望自动生成 Id...
我只添加了

@NaturalId

和

@GeneratedValue(strategy=GenerationType.SEQUENCE)

我也试过 GenerationType.AUTO
但没有用。
请建议。

Answer 1

此问题有一种解决方法。我遇到了同样的情况，有 4 个字段作为复合键，其中 1 个需要按顺序生成。
我根本没有创建嵌入式类，只有 1 个需要按顺序生成的 @Id 字段。其余所有字段值将是简单列，因为在 DB 中强制执行参照完整性，而且我正在检查代码中其余 3 个字段的值是否为空。

如果出现错误，事务将回滚。