我想在我的Spring Boot项目中使用Spring Data Rest但是我遇到了困难 . 我使用的是Spring启动版2.0.0.M2 . 我也试过版本1.5.4.RELEASE但是得到了同样的错误
我在我的pom中使用以下导入
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
<exclusions>
<exclusion>
<groupId>org.apache.tomcat</groupId>
<artifactId>tomcat-jdbc</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-rest</artifactId>
</dependency>
我的DB对象如下
@Entity
@Table(name = "T_PUBLICATION")
public class PublicationDBO implements Serializable{
private static final long serialVersionUID = -8883649751668748295L;
@Id
@Column(name = "id")
private Long id;
@Column(name = "publication_name")
private String publicationName;
@Column(name = "number_of_pages")
private Long numberOfPages;
@Column(name = "storage_key")
private String storageKey;
@Column(name = "processing_complete")
private Boolean processingComplete;
@Column(name = "date_added")
private LocalDateTime dateAdded;
@Column(name = "date_updated")
private LocalDateTime dateUpdated;
}
数据库SQL(MySQL DB)
CREATE TABLE `T_PUBLICATION` (
`id` int(11) NOT NULL,
`publication_name` varchar(255) NOT NULL,
`number_of_pages` int(11) NOT NULL,
`storage_key` varchar(255) NOT NULL,
`processing_complete` tinyint(1) NOT NULL,
`date_added` datetime NOT NULL,
`date_updated` datetime NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
存储库类
import org.springframework.data.repository.PagingAndSortingRepository;
import org.springframework.data.rest.core.annotation.RepositoryRestResource;
import com.dao.vo.PublicationDBO;
@RepositoryRestResource(collectionResourceRel = "publication", path = "publication")
public interface PublicationRepository extends PagingAndSortingRepository<PublicationDBO, Long>{
}
当我尝试访问Spring Data和此对象的 endpoints 时 - 我收到以下错误
2017-07-17 16:03:28 [http-nio-8080-exec-1] DEBUG org.hibernate.SQL - select publicatio0_.id as id1_1_0_, publicatio0_.date_added as date_add2_1_0_, publicatio0_.date_updated as date_upd3_1_0_, publicatio0_.number_of_pages as number_o4_1_0_, publicatio0_.processing_complete as processi5_1_0_, publicatio0_.publication_name as publicat6_1_0_, publicatio0_.storage_key as storage_7_1_0_ from T_PUBLICATION publicatio0_ where publicatio0_.id=?
Hibernate: select publicatio0_.id as id1_1_0_, publicatio0_.date_added as date_add2_1_0_, publicatio0_.date_updated as date_upd3_1_0_, publicatio0_.number_of_pages as number_o4_1_0_, publicatio0_.processing_complete as processi5_1_0_, publicatio0_.publication_name as publicat6_1_0_, publicatio0_.storage_key as storage_7_1_0_ from T_PUBLICATION publicatio0_ where publicatio0_.id=?
2017-07-17 16:03:28 [http-nio-8080-exec-1] WARN o.s.w.s.m.s.DefaultHandlerExceptionResolver - Failed to write HTTP message: org.springframework.http.converter.HttpMessageNotWritableException: Could not write JSON: java.lang.String cannot be cast to java.lang.Long; nested exception is com.fasterxml.jackson.databind.JsonMappingException: java.lang.String cannot be cast to java.lang.Long (through reference chain: org.springframework.data.rest.webmvc.json.PersistentEntityJackson2Module$PersistentEntityResourceSerializer$1["content"]->com.dao.vo.PublicationDBO["publicationName"])
2017-07-17 16:03:28 [http-nio-8080-exec-1] WARN o.s.w.s.m.s.DefaultHandlerExceptionResolver - Resolved exception caused by Handler execution: org.springframework.http.converter.HttpMessageNotWritableException: Could not write JSON: java.lang.String cannot be cast to java.lang.Long; nested exception is com.fasterxml.jackson.databind.JsonMappingException: java.lang.String cannot be cast to java.lang.Long (through reference chain: org.springframework.data.rest.webmvc.json.PersistentEntityJackson2Module$PersistentEntityResourceSerializer$1["content"]->com.dao.vo.PublicationDBO["publicationName"])
Note: 我尝试使用标准服务类进行JPA调用,并且他们第一次工作,因此映射到我的数据库表的实体是正确的
任何人都可以提供任何帮助,说明为什么会这样吗?我检查了我的数据库映射,看起来没问题
谢谢Damien
2 回答
我认为你不是发送'id'作为你的JSON的一部分 . 您可能已经假定id是自动创建的,并且假设您想要在JSON对象中发送id)在您的Entity定义中将id添加
@JsonIgnore
到id . 如果这样做,在查询时也不会在返回对象中包含Id字段 . 如果你想要id,在你的JSON中发送一个null或“”(空字符串) . 有时,Spring引导可能会忽略这些空字段 . 应该有另一个@Json ...注释来指示它不要忽略null / empty值 . 我无法理解它,你必须谷歌它 .根据这篇文章 - https://github.com/spring-projects/spring-boot/issues/9756将Spring Boot版本从2.0.0.M1更改为2.0.0.BUILD-SNAPSHOT已解决问题