Java 使用 spring 数据 jpa 更新单个字段
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Update single field using spring data jpa
提问by Dmitrii Borovoi
I'm using spring-data's repositories - very convenient thing but I faced an issue. I easily can update whole entity but I believe it's pointless when I need to update only a single field:
我正在使用 spring-data 的存储库 - 非常方便，但我遇到了一个问题。我可以轻松地更新整个实体，但我相信当我只需要更新一个字段时它毫无意义：
@Entity
@Table(schema = "processors", name = "ear_attachment")
public class EARAttachment {
private Long id;
private String originalName;
private String uniqueName;//yyyy-mm-dd-GUID-originalName
private long size;
private EARAttachmentStatus status;
to update I just call method save. In log I see the followwing:
更新我只是调用方法保存。在日志中，我看到以下内容：
batching 1 statements: 1: update processors.ear_attachment set message_id=100,
original_name='40022530424.dat',
size=506,
status=2,
unique_name='2014-12-16-8cf74a74-e7f3-40d8-a1fb-393c2a806847-40022530424.dat'
where id=1
I would like to see some thing like this:
我想看到这样的事情：
batching 1 statements: 1: update processors.ear_attachment set status=2 where id=1
Spring's repositories have a lot of facilities to select something using name conventions, maybe there is something similar for update like updateForStatus(int status);
Spring 的存储库有很多工具可以使用名称约定来选择某些内容，也许有类似 updateForStatus(int status); 之类的更新功能。
采纳答案by Bruno César
You can try something like this on your repository interface:
您可以在存储库界面上尝试这样的操作：
@Modifying
@Query("update EARAttachment ear set ear.status = ?1 where ear.id = ?2")
int setStatusForEARAttachment(Integer status, Long id);
You can also use named params, like this:
您还可以使用命名参数，如下所示：
@Modifying
@Query("update EARAttachment ear set ear.status = :status where ear.id = :id")
int setStatusForEARAttachment(@Param("status") Integer status, @Param("id") Long id);
The int return value is the number of rows that where updated. You may also use voidreturn.
int 返回值是更新的行数。您也可以使用void返回。
See more in referencedocumentation.
在参考文档中查看更多信息。
回答by Vijai
Hibernate offers the @DynamicUpdate annotation. All we need to do is to add this annotation at the entity level:
Hibernate 提供了 @DynamicUpdate 注释。我们需要做的就是在实体层面添加这个注解：
@Entity(name = "EARAttachment ")
@Table(name = "EARAttachment ")
@DynamicUpdate
public class EARAttachment {
//Code omitted for brevity
}
Now, when you use EARAttachment.setStatus(value)and executing "CrudRepository" save(S entity), it will update only the particular field. e.g. the following UPDATE statement is executed:
现在，当您使用EARAttachment.setStatus(value)和执行 "CrudRepository" 时save(S entity)，它只会更新特定字段。例如，执行以下 UPDATE 语句：
UPDATE EARAttachment
SET status = 12,
WHERE id = 1
回答by Fabricio Souza
You can update use databind to map @PathVariable T entity and @RequestBody Map body. And them update body -> entity.
您可以更新使用数据绑定来映射 @PathVariable T 实体和 @RequestBody 映射主体。然后他们更新 body -> entity。
public static void applyChanges(Object entity, Map<String, Object> map, String[] ignoreFields) {
map.forEach((key, value) -> {
if(!Arrays.asList(ignoreFields).contains(key)) {
try {
Method getMethod = entity.getClass().getMethod(getMethodNameByPrefix("get", key));
Method setMethod = entity.getClass().getMethod(getMethodNameByPrefix("set", key), getMethod.getReturnType());
setMethod.invoke(entity, value);
} catch (IllegalAccessException | NoSuchMethodException | InvocationTargetException e) {
e.printStackTrace();
}
}
});
}
