java - 使用 hibernate 将枚举值插入表

Question

我需要用可能的值 1--> 男性，2 --> 女性填充具有性别字段的员工表

表的 Hibernate 映射:

package test.hib.entity;

import java.io.Serializable;

import javax.persistence.Column;
import javax.persistence.Convert;
import javax.persistence.Entity;
import javax.persistence.EnumType;
import javax.persistence.Enumerated;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

import test.hib.enumtest.GenderConverter;

@Entity
@Table(name="Employee")
public class Employee implements Serializable {

    /**
     * 
     */
    private static final long serialVersionUID = -2531499686831259894L;

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private int employeeId;

    @Column
    private String employeeName;

    @Column
    @Convert(converter=GenderConverter.class)
    private Gender gender;

    public int getEmployeeId() {
        return employeeId;
    }

    public void setEmployeeId(int employeeId) {
        this.employeeId = employeeId;
    }

    public String getEmployeeName() {
        return employeeName;
    }

    public void setEmployeeName(String employeeName) {
        this.employeeName = employeeName;
    }

    public Gender getGender() {
        return gender;
    }

    public void setGender(Gender gender) {
        this.gender = gender;
    }




}

性别枚举:

package test.hib.entity;

public enum Gender {
    MALE(1),
    FEMALE(2);

    private int value;

    private Gender(int value){
        this.value = value;
    }

    public int getValue() {
        return value;
    }



    public static Gender getGender(Integer id) {
        if (id == null)
            return null;
        for (Gender g : values()) {
            if (g.getValue() == id)
                return g;
        }
        return null;
    }

}

转换器:

package test.hib.enumtest;

import javax.persistence.AttributeConverter;
import javax.persistence.Converter;

import test.hib.entity.Gender;

@Converter
public class GenderConverter implements AttributeConverter<Gender, Integer>{

    @Override
    public Integer convertToDatabaseColumn(Gender arg0) {
        if(arg0 != null) return arg0.getValue();
        return null;
    }

    @Override
    public Gender convertToEntityAttribute(Integer arg0) {
        // TODO Auto-generated method stub
        return Gender.getGender(arg0);
    }

}

我使用下面的代码来修改实体，

ApplicationContext applicationContext = new ClassPathXmlApplicationContext("springConfig.xml");
HibEnumRepo repository = (HibEnumRepo)applicationContext.getBean(HibEnumRepo.class);

Employee employee = new Employee();
employee.setEmployeeName("Renjith");
employee.setGender(Gender.MALE);


repository.insertEmployee(employee);

Employee employee2 = new Employee();
employee2.setEmployeeName("Renju");
employee2.setGender(Gender.FEMALE);


repository.insertEmployee(employee2);

内部存储库 bean。

package test.hib.enumtest;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;
import org.springframework.transaction.annotation.Transactional;

import test.hib.entity.Employee;

    @Repository
    public class HibEnumRepo {

        @Autowired
        private SessionFactory sessionFactory;

        @Transactional
        public void insertEmployee(Employee employee){
            Session session = sessionFactory.getCurrentSession();

            session.save(employee);
        }
    }

但是在将值插入表时，枚举设置了男性和女性的默认值，即。分别为 0 和 1。

mysql> select * from Employee;
+------------+--------------+--------+
| employeeId | employeeName | gender |
+------------+--------------+--------+
|          1 | Renjith      |      0 |
|          2 | Renju        |      1 |
+------------+--------------+--------+
2 rows in set (0.00 sec)

我如何设置值 1 和 2？

Answer 1

最好将 enum 作为 String 存储在数据库中，并使用 enum 从应用程序中检索它的 id。

您正在保留从 0 开始的 enum 的 EnumType.ORDINAL，这就是 0 和 1 在 DB 中保留的原因

如果你希望枚举的 id 被持久化，你可以使用 Coverter 注释

转换在 JPA2.1 (Hibernate 4.3+) 中添加

实体

@Entity
public class Employee {

    @Id
    @GeneratedValue
    Long id;

    @Column
    String name;

    @Column
    int age;

    @Column
    @Convert(converter = GenderConverter.class)
    Gender gender;
}

转换器

public class GenderConverter implements AttributeConverter<Gender, Integer> {

    @Override
    public Integer convertToDatabaseColumn(Gender gender) {
        if (gender == null)
            return null;
        return gender.getId();
    }

    @Override
    public Gender convertToEntityAttribute(Integer id) {
        return Gender.getGender(id);
    }

}

枚举

public enum Gender {
    MALE(1), FEMALE(2);
    int id;

    private Gender(int id) {
        this.id = id;
    }

    public int getId() {
        return id;
    }

    public static Gender getGender(Integer id) {
        if (id == null)
            return null;
        for (Gender g : values()) {
            if (g.getId() == id)
                return g;
        }
        return null;
    }
}

由hibernate创建的DDL

Hibernate: create table employee (id bigint generated by default as identity, age integer, gender integer, name varchar(255), primary key (id))