Spring Data Rest (SDR) 错误?持久实体不能为空 [英] Spring Data Rest (SDR ) bug? Persistent Entity Must not be null
问题描述
目前我正在为 Spring Data Rest 开发 POC.试图从存储库中获取可行的 JSONout.
Currently I am working on a POC for Spring Data Rest. Trying to get workable JSONout of a repository.
我有一个实体类(NewTask)
I have an Entity Class (NewTask)
@Entity
@Table(name="newtable")
public class NewTask {
@Id
@Column(name="newid")
private int id;
@Column(name="newage")
private int age;
@Column(name="newaddress")
private String address;
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
}
和相应的存储库..
@RepositoryRestResource
@PreAuthorize("hasRole('ROLE_ADMIN')")
public interface NewTaskRepository extends CrudRepository<NewTask, Serializable>{
@Query("SELECT t.address FROM NewTask t where t.id = :id")
String findByMyId(@Param("id") int id);
}
每当我点击
http://localhost:8080/POCDB/newTasks/search/findByMyId?id=1
我收到以下错误:{"cause":null,"message":"PersistentEntity 不能为空!"}
I get the following error: {"cause":null,"message":"PersistentEntity must not be null!"}
现在这是我的存储库的外观:请阅读每个方法的评论
Now here is how my repository looks: Please read the comments on each method
//Gives- PersistentEntity must not be null!!!
@Query("SELECT t.address FROM NewTask t where t.id = :id")
String findByMyId(@Param("id") int id);
//WORKS FINE
@Query("SELECT t.id FROM NewTask t where t.id = :id")
int findId(@Param("id") int id);
//WORKS FINE
@Query("SELECT t.id FROM NewTask t where t.id = :id")
Integer findIdTwo(@Param("id") int id);
//Gives- PersistentEntity must not be null!!!
@Query("SELECT t.id FROM NewTask t")
List<Integer> findIds();
我不确定返回类型有什么问题.我参考了下面的链接以获得一些解决方案:
I am not sure what are the issues with return types.I referred the link below for some solution:
如何在 jparepository 中创建自定义查询但返回实体以外的对象?
并向我的 Repository 添加了另外 2 个方法,这些方法对我不起作用
and added 2 more methods to my Repository, which don't work for me
// returns in some weird format
@Query("SELECT t.address FROM NewTask t where t.id = :id")
PString findByMyId(@Param("id") int id);
//Gives- PersistentEntity must not be null!!!
@Query("SELECT t.address FROM NewTask t")
List<PString> findAddress();
我有预感这是 SDR 中的错误,还是我遗漏了什么?
I have a hunch this is a bug in SDR, or am I missing something?
推荐答案
Spring Data REST 只能返回已注册存储库的数据.在您引用的另一个问题中,您会注意到他们专门为他们需要的类型创建了一个自定义存储库.这不是 SDR 中的错误,而是它的运作方式.它还保持 RESTful.
Spring Data REST can only return data for which the repository is registered for. In the other question that you reference, you'll notice that they created a custom repository specifically for the type that they needed. This isn't a bug in SDR, it's just how it functions. It also keeps it RESTful.
因此,在您的情况下,SDR 只能返回 NewTask 或 NewTask 的集合.
So in your case, SDR can only return NewTask or collections of NewTask.
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