我有两个实体 AppUser
和 UserGroup
。他们有一个 @ManyToMany
关系。
我目前正在尝试为现有用户创建和关联一个新组,如下所示:
POST http://localhost:8080/groups
{
"name": "Group 1",
"users": ["http://localhost:8080/users/1"]
}
问题是只有组被创建 - 但没有与列出的用户关联 - 服务器仍然响应 201 Created
?!
这是两个存储库:
@RepositoryRestResource(collectionResourceRel = "users", path = "users")
public interface AppUserRepository extends JpaRepository<AppUser, Long> {
AppUser findByUsername(@Param("username") String username);
}
@RepositoryRestResource(collectionResourceRel = "groups", path = "groups")
public interface UserGroupRepository extends JpaRepository<UserGroup, Long> {
List<UserGroup> findByName(@Param("name") String name);
}
下面你可以看到关系是如何定义的:
应用用户.java
@Column(name="user_group_id")
@ManyToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
@JoinTable(name = "app_user__user_group",
joinColumns = {
@JoinColumn(name = "app_user_id", nullable = false, updatable = false) },
inverseJoinColumns = {
@JoinColumn(name = "user_group_id", nullable = false, updatable = false)})
private Set<UserGroup> groups;
用户组.java
@Column(name = "app_user_id")
@ManyToMany(fetch = FetchType.LAZY, mappedBy = "groups")
private Set<AppUser> users;
注意:
如果我只传递一个字符串,而不是 users
的列表:
POST http://localhost:8080/groups
{
"name": "Group 1",
"users": "http://localhost:8080/users/1"
}
我得到的是:
{
"cause": {
"cause": null,
"message": "Cannot deserialize instance of java.util.Set out of VALUE_STRING token at [Source: (org.apache.catalina.connector.CoyoteInputStream); line: 7, column: 12] (through reference chain: mahlzeit.api.hibernate.model.UserGroup["users"])"
},
"message": "JSON parse error: Cannot deserialize instance of java.util.Set out of VALUE_STRING token; nested exception is com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize instance of java.util.Set out of VALUE_STRING token at [Source: (org.apache.catalina.connector.CoyoteInputStream); line: 7, column: 12] (through reference chain: mahlzeit.api.hibernate.model.UserGroup["users"])"
}
最佳答案
尝试
@Column(name = "app_user_id")
@ManyToMany(fetch = FetchType.LAZY, mappedBy = "groups",cascade = CascadeType.ALL)
private Set<AppUser> users;
最终通过用户列表
{
"name": "Group 1",
"users": ["http://localhost:8080/users/1"]
}
对于 Cannot deserialize instance of java.util.Set 错误 它需要一个用户列表而不是单个用户的实例
关于spring - 创建新实体加关联不起作用,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/47376620/