无法转换实体中具有@IdClass的请求元素

java hibernate spring spring-data

2022-09-03 12:41:57

我有以下设置：

@Entity
@IdClass(MemberAttributePk.class)
public class MemberAttribute {
    @Id
    @ManyToOne @JoinColumn(name="member_id")
    protected Member member;

    @Id
    protected String name;

    private String value;

    public MemberAttribute() {}

    // get & set
}

和 id 类：

public class MemberAttributePk implements Serializable {
    protected Member member;
    protected String name;

    public MemberAttributePk() {}

    // get & set
}

我为以下位置定义了一个简单的 Spring Data 存储库：MemberAttribute

@Repository
public interface MemberAttributeRepo extends JpaRepository<MemberAttribute, MemberAttributePk> {
}

现在，我想做的就是将成员属性保存到数据库中：

public void saveAttribute(Member member, String name, String value) {
    MemberAttribute attr = new MemberAttribute(member, name, value);
    attributeRepo.save(attr);
}

但是，我最终会遇到此服务器异常：

2016-08-28 00:24:20.673  WARN 5656 --- [nio-8080-exec-8] .w.s.m.s.DefaultHandlerExceptionResolver : 
Failed to convert request element: org.springframework.beans.ConversionNotSupportedException: 
Failed to convert property value of type [java.lang.Long] to required type [com.example.Member] for property 'member'; nested exception is java.lang.IllegalStateException: 
Cannot convert value of type [java.lang.Long] to required type [com.example.Member] for property 'member': 
no matching editors or conversion strategy found

你知道我做错了什么吗？谢谢！

答案 1

只是你的代码不符合JPA。问题的原因是您用作 PK 的一部分。PK 只能由以下 Java 类型的字段组成。Member

基元：布尔值，字节，字符，整数，长整型，短整型

java.lang ：布尔值，字节，字符，整数，长整型，短整型，字符串，枚举，字符串缓冲区

java.math ： BigInteger java.sql ：日期，时间，时间戳

java.util ：日期，货币，区域设置，时区， UUID

java.net ： URI， URL

javax.jdo.spi ： PersistenceAbility

这应该有效：

@Embeddable
public class MemberAttributePk implements Serializable {
    @Column(name = "member_id")
    protected Long memberId;
    @Column(name = "name")
    protected String name;

    public MemberAttributePk() {}

    // get & set
}

@Entity
public class MemberAttribute {

    @EmbeddedId
    protected MemberAttributePk memberAttributePk;

    @ManyToOne 
    @JoinColumn(name="member_id")
    protected Member member;

    private String value;

    public MemberAttribute() {}

    // get & set
}

或与@ClassId

public class MemberAttributePk implements Serializable {
    protected Long memberId;
    protected String name;

    public MemberAttributePk() {}

    // get & set
}

@Entity
@IdClass(MemberAttributePk.class)
public class MemberAttribute {
    @Id
    @Column(name = "member_id")
    protected Long memberId;

    @Id
    @Column(name = "name")
    protected String name;

    @ManyToOne 
    @JoinColumn(name="member_id")
    protected Member member;

    private String value;

    public MemberAttribute() {}

    // get & set
}

答案 2

你可以尝试使用你的MemberRepository保存它，因为我相信你的Member类和MemberAttribute类有一对多的关系参考，下面是一个例子

成员类

@Entity
public class Member {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    public long id;

    @OneToMany(mappedBy = "Member", cascade = CascadeType.ALL)
     private Set<MemberAttribute> mMemberAttributes = new HashSet<>();

     public void setMemberAttributes(Set<MemberAttribute> mMemberAttributes){
        this.mMemberAttributes = mMemberAttributes;
     }

     public Set<MemberAttribute> getMemberAttributes(){
         return mMemberAttributes;
     }

     // other code
}

成员存储库类

public interface MemberRepository extends JpaRepository<Member, Long> {

}

保存函数中的代码

public void saveAttribute(Member member, String name, String value) {
    MemberAttribute attr = new MemberAttribute(member, name, value);
    member.getMemberAttributes().add(attr);
    memberRepository.save(member);
}