JPA Hibernate一对一关系错误

Question

我正在尝试实现 OneToOne 关系 bw 3 个实体，但面临这个与哈希码相关的错误。我在 2 个类中有 3 个类，我正在尝试访问一个 companyaccessright 实体。

公司访问权限-

@Entity
@Table(name = "company_access_rights")
@Data
@EqualsAndHashCode(callSuper = true)
@NoArgsConstructor
public class CompanyAccessRights{

}

@Entity
@Table(name = "companies")
@Data
@EqualsAndHashCode(callSuper = true)
@NoArgsConstructor
public class Company{
    @OneToOne
    @JoinColumn(name = "company_access_rights")
    private  CompanyAccessRights companyAccessRights;
}

@Entity
@Table(name = "company_employment_settings")
@Data
@EqualsAndHashCode(callSuper = true)
@NoArgsConstructor
public class CompanyEmploymentSettings{
   @OneToOne
    @JoinColumn(name = "company_access_rights")
    private  CompanyAccessRights companyAccessRights;
}

ERROR [28.02.2023 11:12:10,974]: [] [] org.apache.catalina.core.ContainerBase.[Tomcat].[localhost].[/].[dispatcherServlet] - Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Filter execution threw an exception] with root cause
java.lang.StackOverflowError: null
    at ch.talmatch.app.domain.company.Company.hashCode(Company.java:19) ~[classes/:?]
    at ch.talmatch.app.domain.company.CompanyEmploymentSettings.hashCode(CompanyEmploymentSettings.java:33) ~[classes/:?]
    at ch.talmatch.app.domain.company.Company.hashCode(Company.java:19) ~[classes/:?]
    at ch.talmatch.app.domain.company.CompanyEmploymentSettings.hashCode(CompanyEmploymentSettings.java:33) ~[classes/:?]
    at ch.talmatch.app.domain.company.Company.hashCode(Company.java:19) ~[classes/:?]
    at ch.talmatch.app.domain.company.CompanyEmploymentSettings.hashCode(CompanyEmploymentSettings.java:33) ~[classes/:?]
    at ch.talmatch.app.domain.company.Company.hashCode(Company.java:19) ~[classes/:?]
    at ch.talmatch.app.domain.company.CompanyEmploymentSettings.hashCode(CompanyEmploymentSettings.java:33) ~[classes/:?]
    at ch.talmatch.app.domain.company.Company.hashCode(Company.java:19) ~[classes/:?]
    at ch.talmatch.app.domain.company.CompanyEmploymentSettings.hashCode(CompanyEmploymentSettings.java:33) ~[classes/:?]
    at ch.talmatch.app.domain.company.Company.hashCode(Company.java:19) ~[classes/:?]
    at ch.talmatch.app.domain.company.CompanyEmploymentSettings.hashCode(CompanyEmploymentSettings.java:33) ~[classes/:?]
    at ch.talmatch.app.domain.company.Company.hashCode(Company.java:19) ~[classes/:?]
    at ch.talmatch.app.domain.company.CompanyEmploymentSettings.hashCode(CompanyEmploymentSettings.java:33) ~[classes/:?]
    at ch.talmatch.app.domain.company.Company.hashCode(Company.java:19) ~[classes/:?]
    at ch.talmatch.app.domain.company.CompanyEmploymentSettings.hashCode(CompanyEmploymentSettings.java:33) ~[classes/:?]
    at ch.talmatch.app.domain.company.Company.hashCode(Company.java:19) ~[classes/:?]
    at ch.talmatch.app.domain.company.CompanyEmploymentSettings.hashCode(CompanyEmploymentSettings.java:33) ~[classes/:?]

Answer 1

问题不在于

CompanyAccessRights

，而在于两者：

• Company

  包含对

  CompanyAccessRights

  和
的引用

• CompanyAccessRights

  包含对

  Company

的引用

lomboks

@EqualsAndHashCode

正在通过在所有复杂类型字段上调用

hashCode()

方法来计算哈希码，所以问题是

CompanyAccessRights.hashCode()

正在调用

Company.hashCode()

然后

Company.hashCode()

正在调用

CompanyAccessRights.hashCode()

一次又一次，直到你用完所有的堆栈内存——StackOverflowException。

要解决这个问题，您可以删除其中一个字段，或者您可以用

@EqualsAndHashCode.Exclude

标记这些字段以在 hashCode 计算中排除该字段

Answer 2

尝试使用

fetch = FetchType.LAZY

来建立

@OneToOne

关系；

@OneToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "company_access_rights")
private  CompanyAccessRights companyAccessRights;

希望能解决你的问题