Question

我的id类如下，

public class EmployeeId implements Serializable{
    public EmployeeId(){}
    public EmployeeId(Integer id, String country){
        this.id = id;
        this.country = country;
    }

    private Integer id;
    private String country;

    @Override
    public int hashCode(){        
        return this.getCountry().hashCode() + getId();
    }

    @Override
    public boolean equals(Object o){
        boolean flag = false;
        EmployeeId myId = (EmployeeId) o;

        if((o instanceof EmployeeId) 
                && (this.getCountry().equals(myId.getCountry()))
                && (this.id == myId.getId())){
            flag = true;
        }
        return flag;
    }
// rest of the code with getters only
}

以下是我的实体使用

@Entity
@IdClass(EmployeeId.class)
@Table(name="TBL_EMPLOYEE_FOUR")
public class EmployeeEntityTwo {

    public EmployeeEntityTwo(){}
    public EmployeeEntityTwo(Integer id,String country, String empName){
        this.country = country;
        this.employeeId = id;
        this.empName = empName;
    }

    @Id
    @Column(name="ID")
    private Integer employeeId;

    @Id
    @Column(name="COUNTRY",length=50)
    private String country;

    @Column(name="NAME",length=50)
    private String empName;
// getters and setters
}

这是我的表

create table TBL_EMPLOYEE_FOUR(
    ID integer, 
    COUNTRY varchar(50),
    NAME varchar(50),
    constraint PK_EMP_00239 primary key(ID,COUNTRY)
)

这就是我想要运行的

 private static void idClassStore(EntityManager em) throws Exception{
     List<EmployeeEntityTwo> employees = Arrays.asList(new EmployeeEntityTwo(12, "KENYA", "Ridushi Ogambe"),
                                                       new EmployeeEntityTwo(13, "GHANA", "Mikila Hanza"),
                                                       new EmployeeEntityTwo(14, "EGYPT", "Abdul Hameed Fagdaul"),
                                                       new EmployeeEntityTwo(15, "MOROCCO", "Jamil Mahmoud"),
                                                       new EmployeeEntityTwo(16, "LIBERIA", "Robert Damus"));

     for(EmployeeEntityTwo employee : employees){
         em.persist(employee);            
       }
}

但我得到一个例外

Caused by: org.hibernate.AnnotationException: Property of @IdClass not found in entity com.entities.EmployeeEntityTwo: id

我使用JPA和Hibernate作为持久性提供程序，

但我使用的@IdClass是导入javax.persistence.IdClass;

所以哪里出错了，

Answer 1

我发现了解决方案：

班级EmployeeEntityTwo和EmployeeId中的“id”字段应相同。

// EmployeeId.java;
private Integer id;

应该是

// EmployeeId.java;
private Integer employeeId;

我分别调整了吸气剂，它起作用了。

来自javax.persistence.IdClass JavaDocs：

主键类中的字段或属性的名称以及实体的主键字段或属性必须对应，并且它们的类型必须相同。

使用@IdClass存储具有复合主键的实体，但无法持久化

1 个答案: