Java Spring-Data-Jpa 存储库 - 实体列名称上的下划线
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Spring-Data-Jpa Repository - Underscore on Entity Column Name
提问by George Siggouroglou
I am using spring-data-jpa on a spring webmvc project. I am facing an issue using query creationon a Repository of one of my Entities. Below you can see my Entity, my Repository and the Exception.
我在 spring webmvc 项目上使用 spring-data-jpa。我在我的一个实体的存储库上使用查询创建时遇到问题。您可以在下面看到我的实体、我的存储库和异常。
My Entity:
我的实体：
@Entity
@Table(schema = "mainschema")
@XmlRootElement
public class Municipalperson implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Basic(optional = false)
@Column(nullable = false)
private Integer id;
@Basic(optional = false)
@Column(name = "municipal_id", nullable = false)
private Integer municipal_id;
@Basic(optional = false)
@Column(nullable = false, length = 60)
private String firstname;
public Municipalperson(Integer id, Integer municipal_id, String firstname) {
this.id = id;
this.municipal_id = municipal_id;
this.firstname = firstname;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public Integer getMunicipal_id() {
return municipal_id;
}
public void setMunicipal_id(Integer municipal_id) {
this.municipal_id = municipal_id;
}
public String getFirstname() {
return firstname;
}
public void setFirstname(String firstname) {
this.firstname = firstname;
}
}
my Repository:
我的存储库：
@Repository
public interface MunicipalpersonRepository extends JpaRepository<Municipalperson, Integer> {
List<Municipalperson> findByMunicipal_idOrderByLastnameDesc(int municipal_id);
}
and the exception,
和例外，
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'municipalpersonRepository': Invocation of init method failed; nested exception is org.springframework.data.mapping.PropertyReferenceException: No property municipal found for type Municipalperson!
I tried to set municipal_idas int, then as Integerand the same for the parameter municipal_idon my Repository, but none worked. Also, I renamed the Repository to findByMunicipalidOrderByLastnameDescand findByMunicipalIdOrderByLastnameDescbut it didn't work either.
我尝试将存储库上的参数设置municipal_id为 int，然后设置为Integer相同municipal_id，但没有任何效果。另外，我将 Repository 重命名为findByMunicipalidOrderByLastnameDescandfindByMunicipalIdOrderByLastnameDesc但它也不起作用。
Finally I renamedthe municipal_idto municipalId(underscore removed) and also renamed getters/setters and the Repository (findByMunicipalIdOrderByLastnameDesc) and the issue was resolved.
最后，我将其重命名municipal_id为municipalId（删除了下划线）并重命名了 getter/setter 和 Repository ( findByMunicipalIdOrderByLastnameDesc)，问题就解决了。
My question is why this is happening?
我的问题是为什么会这样？
采纳答案by Oliver Drotbohm
The underscore _is a reserved character in Spring Data query derivation (see the reference docsfor details) to potentially allow manual property path description. So there are two options you have:
下划线_是 Spring Data 查询派生中的保留字符（有关详细信息，请参阅参考文档）可能允许手动属性路径描述。所以你有两个选择：
- Stick to the Java naming conventions of using camel-casefor member variable names and everything will work as expected.
- Escape the
_by using an additional underscore, i.e. rename your query method tofindByMunicipal__idOrderByLastnameDesc(…).
- 坚持对成员变量名称使用驼峰命名的 Java 命名约定，一切都会按预期工作。
_使用额外的下划线转义，即将您的查询方法重命名为findByMunicipal__idOrderByLastnameDesc(…).
I'd recommend the former as you're not going to alienate fellow Java developers :).
我推荐前者，因为您不会疏远其他 Java 开发人员:)。
回答by Valentyn Kolesnikov
I solved this error by renaming field to the name without underscore.
我通过将字段重命名为不带下划线的名称解决了这个错误。
@Column(name = "municipal_id", nullable = false)
private Integer municipalId; // <-- field was renamed
回答by Jagannath Nanda
Please add the following properties to application.propertiesfile:
请将以下属性添加到application.properties文件：
spring.jpa.hibernate.naming-strategy=org.hibernate.cfg.ImprovedNamingStrategy
