JAVAlang.ClassCastException:JobEntity不能转换为JobExtrapt（使用Spring数据投影）

Question

使用投影获取实体类JobEntity的特定字段，使用JobExtrapt

作业实体类：https://pastebin.com/GPeQDiRp

作业摘录类：

@Projection(
        name = "jobProjection",
        types = { JobEntity.class })
public interface JobExcerpt {
    Long getId();

    JobEntity.Status getStatus();

    List<BatchEntity> getBatches();

    Date getCreatedOn();

    Long getRetailerId();
}

非常简单的作业摘录存储库类：

@RepositoryRestResource(excerptProjection = JobExcerpt.class)
public interface JobExcerptRepository extends JpaRepository<JobEntity, Long> {

    JobExcerpt findByIdAndRetailerId(Long jobId, Long retailerId);

}

失败的代码行：

JobExcerpt jobExcerpt = jobExcerptRepository.findByIdAndRetailerId(jobId, retailerId);

问题是。。。这行代码中没有可见的（强制转换）类运算符。它不应该被显示，对吗

堆栈跟踪： https://pastebin.com/iNG8h5dn

Answer 1

你似乎重新运行了一个工作摘要预测。这就是为什么你有ClassCastException。应该是这样的

@RepositoryRestResource(excerptProjection = JobExcerpt.class)
public interface JobExcerptRepository extends JpaRepository<JobEntity, Long> {

    JobEntity findByIdAndRetailerId(Long jobId, Long retailerId);

}

JobEntity jobEntity = jobExcerptRepository.findByIdAndRetailerId(jobId, retailerId);

Answer 2

如果你想从你的领域获得特定的领域。然后你可以简单地做这些事情

// JobExcerpt.java

public interface JobExcerpt {

    Long getId();

    Status getStatus();

    List<BatchEntity> getBatches();

    Date getCreatedOn();

    Long getRetailerId();
}

//  JobExcerptRepository.java
@RepositoryRestResource(excerptProjection = JobExcerpt.class)
public interface JobExcerptRepository extends JpaRepository<JobEntity, Long> {

    JobExcerpt findByIdAndRetailerId(Long jobId, Long retailerId);

}

JobExcerpt jobExcerpt = jobExcerptRepository.findByIdAndRetailerId(jobId, retailerId)