Spring Data Rest歧义关联异常 [英] Spring Data Rest Ambiguous Association Exception
问题描述
由于域类中的关联不明确，新添加的LinkCollectingAssociationHandler抛出了MappingException.
The newly added LinkCollectingAssociationHandler is throwing a MappingException due to an ambiguous association in my domain class.
links数组看起来像这样:
The links array looks like this:
[<http://localhost:8080/rooms/2/roomGroups>;rel="roomGroups", <http://localhost:8080/rooms/2/userGroup>;rel="userGroup", <http://localhost:8080/rooms/2/room>;rel="room", <http://localhost:8080/rooms/2/originatingConferences>;rel="originatingConferences", <http://localhost:8080/rooms/2/user>;rel="user"]
当它引发异常时，它正在尝试添加另一个房间"关系.
And it is trying to add another 'room' relation when it throws the exception.
问题在于，它似乎正在向我用@RestResource(exported = false)
The issue is that it seems to be adding links to relations which I have explicitly marked with @RestResource(exported = false)
以下是我认为导致此问题的一种关系示例:
Here is an example of a relation which I believe is causing this issue:
@JsonIgnore
@RestResource(exported = false)
@OneToMany(fetch = FetchType.LAZY, mappedBy = "pk.room", cascade = {CascadeType.REMOVE})
private Set<RoomsByUserAccessView> usersThatCanDisplay = new HashSet<>();
类型RoomsByUserAccessView具有由Room和User组成的嵌入式ID.
The type RoomsByUserAccessView has an embedded id made up of a Room and a User.
我还用以下注释了嵌入式id属性:
I have also annotated the embedded id property with:
@JsonIgnore
@RestResource(exported = false)
private RoomsByUserAccessViewId pk = new RoomsByUserAccessViewId();
及其属性如下:
@JsonIgnore
@RestResource(exported = false)
private Room room;
@JsonIgnore
@RestResource(exported = false)
private User userWithAccess;
public RoomsByUserAccessViewId() {
//
}
在序列化为JSON时如何正确忽略这些关系?
How can I get it to ignore these relations properly when serializing to JSON?
我的代码在DATAREST-262( https://github.com/spring -projects/spring-data-rest/commit/1d53e84cae3d09b09c4b5a9a4caf438701527550 )
My code was working prior to DATAREST-262 (https://github.com/spring-projects/spring-data-rest/commit/1d53e84cae3d09b09c4b5a9a4caf438701527550)
当我尝试访问房间/端点时返回的完整错误消息如下:
The full error message returned when I try to visit the rooms/ endpoint is as follows:
{
timestamp: "2014-03-17T13:38:05.481-0500"
error: "Internal Server Error"
status: 500
exception: "org.springframework.http.converter.HttpMessageNotWritableException"
message: "Could not write JSON: Detected multiple association links with same relation type! Disambiguate association @com.fasterxml.jackson.annotation.JsonIgnore(value=true) @javax.persistence.ManyToOne(fetch=EAGER, cascade=[], optional=true, targetEntity=void) @org.springframework.data.rest.core.annotation.RestResource(description=@org.springframework.data.rest.core.annotation.Description(value=), path=, exported=false, rel=) private com.renovo.schedulerapi.domain.Room com.renovo.schedulerapi.domain.RoomsByUserAccessViewId.room using @RestResource! (through reference chain: org.springframework.hateoas.PagedResources["content"]->java.util.UnmodifiableCollection[0]); nested exception is com.fasterxml.jackson.databind.JsonMappingException: Detected multiple association links with same relation type! Disambiguate association @com.fasterxml.jackson.annotation.JsonIgnore(value=true) @javax.persistence.ManyToOne(fetch=EAGER, cascade=[], optional=true, targetEntity=void) @org.springframework.data.rest.core.annotation.RestResource(description=@org.springframework.data.rest.core.annotation.Description(value=), path=, exported=false, rel=) private com.renovo.schedulerapi.domain.Room com.renovo.schedulerapi.domain.RoomsByUserAccessViewId.room using @RestResource! (through reference chain: org.springframework.hateoas.PagedResources["content"]->java.util.UnmodifiableCollection[0])"
}
{
timestamp: "2014-03-17T13:38:05.481-0500"
error: "Internal Server Error"
status: 500
exception: "org.springframework.http.converter.HttpMessageNotWritableException"
message: "Could not write JSON: Detected multiple association links with same relation type! Disambiguate association @com.fasterxml.jackson.annotation.JsonIgnore(value=true) @javax.persistence.ManyToOne(fetch=EAGER, cascade=[], optional=true, targetEntity=void) @org.springframework.data.rest.core.annotation.RestResource(description=@org.springframework.data.rest.core.annotation.Description(value=), path=, exported=false, rel=) private com.renovo.schedulerapi.domain.Room com.renovo.schedulerapi.domain.RoomsByUserAccessViewId.room using @RestResource! (through reference chain: org.springframework.hateoas.PagedResources["content"]->java.util.UnmodifiableCollection[0]); nested exception is com.fasterxml.jackson.databind.JsonMappingException: Detected multiple association links with same relation type! Disambiguate association @com.fasterxml.jackson.annotation.JsonIgnore(value=true) @javax.persistence.ManyToOne(fetch=EAGER, cascade=[], optional=true, targetEntity=void) @org.springframework.data.rest.core.annotation.RestResource(description=@org.springframework.data.rest.core.annotation.Description(value=), path=, exported=false, rel=) private com.renovo.schedulerapi.domain.Room com.renovo.schedulerapi.domain.RoomsByUserAccessViewId.room using @RestResource! (through reference chain: org.springframework.hateoas.PagedResources["content"]->java.util.UnmodifiableCollection[0])"
}
推荐答案
我有一个非常相似的问题.在两个实体之间添加双向关系时
I had a very similar problem . When adding a bidirectional relationship between two entities
我遇到一个异常"无法编写JSON:检测到多个具有相同关联的关联链接
I got an exception ""Could not write JSON: Detected multiple association links with same
关系类型！"，尝试一些我在这里找到的解决方案
relation type!" , While trying some solutions that i found here
(@JsonIgnore, @JsonIdentity, @RestResource，我还尝试做(该关系已使用@JsonManagedReference和@JsonBackReference正确定义)
(The relation was properly defined with @JsonManagedReference and @JsonBackReference)
没有帮助.
最后，我设法了解到spring数据余量正在尝试
At the end i managed to understand that spring data rest is trying to
弄清楚相关实体是否可链接(在尝试构建
figure out if the related entity is linkable ( while trying to build the json of the
请求的实体
(LinkCollectingAssociationHandler : doWithAssociation -> isLinkableAssociation)
，为此，他正在寻找可处理
, For doing that he is looking for a repository that deals with the
相关实体.在为相关实体添加存储库之后..就像一个超级按钮..
related entity. After adding a repository for the related entity.. works like a charm..
(我想在添加一个仓库之后，正在映射一个RepositoryAwareResourceInformation
(I suppose that after adding a repo a mapping RepositoryAwareResourceInformation is being
为此实体创建的(这是我在调试时看到的).
created for this entity (that is what I saw at debug).
这篇关于Spring Data Rest歧义关联异常的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
