Spring Data JPA- Hibernate多对多关系在链接实体表中插入null [英] Spring data JPA- Hibernate Many to Many relation is inserting null in link entity table
本文介绍了Spring Data JPA- Hibernate多对多关系在链接实体表中插入null的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我与用户之间有很多关系
I have many to many relation between user to role
用户实体:
import java.util.HashSet;
import java.util.Set;
import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import lombok.Data;
import lombok.EqualsAndHashCode;
import lombok.NoArgsConstructor;
import lombok.ToString;
@Entity
@Data
@EqualsAndHashCode(callSuper = false, exclude = {"roles"})
@ToString( exclude = {"roles"})
@NoArgsConstructor
public class User {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String lanId;
@OneToMany(mappedBy = "user", cascade = CascadeType.ALL)
private Set<UserRole> roles = new HashSet<>();
public User(String lanId) {
this.lanId = lanId;
}
// Utility Method to sync on both sides
public void addRole(Role role, boolean isPrivileged) {
UserRole userRole = new UserRole();
userRole.setUser(this);
userRole.setRole(role);
userRole.setPrivileged(isPrivileged);
roles.add(userRole);
role.getUsers().add(userRole);
}
}
角色实体:
import java.util.HashSet;
import java.util.Set;
import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import lombok.Data;
import lombok.EqualsAndHashCode;
import lombok.NoArgsConstructor;
import lombok.ToString;
@Entity
@Data
@EqualsAndHashCode(callSuper = false, exclude = {"users"})
@ToString( exclude = {"users"})
@NoArgsConstructor
public class Role {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String roleName;
@OneToMany(mappedBy = "role" ,cascade = CascadeType.ALL)
private Set<UserRole> users = new HashSet<>();
public Role(String roleName) {
this.roleName =roleName;
}
}
用户角色实体:
import java.io.Serializable;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.ManyToOne;
import lombok.Data;
import lombok.EqualsAndHashCode;
import lombok.NoArgsConstructor;
@Entity
@Data
@EqualsAndHashCode(callSuper = false ,exclude = {"privileged"})
@NoArgsConstructor
public class UserRole implements Serializable {
/**
*
*/
private static final long serialVersionUID = 1L;
@Id
@ManyToOne
private User user;
@Id
@ManyToOne
private Role role;
private boolean privileged;
}
服务等级:
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import com.sample.m2m.dto.RolesDto;
import com.sample.m2m.repository.Role;
import com.sample.m2m.repository.RoleRepository;
import com.sample.m2m.repository.User;
import com.sample.m2m.repository.UserRepository;
@Service
public class SampleService {
@Autowired
private UserRepository userRepo;
@Autowired
private RoleRepository roleRepo;
public void addEntity(String lanId,List<RolesDto> roles) {
// adding roles to DB first
addNewRoles(lanId,roles);
addUserRole(lanId,roles);
}
@Transactional
public void addNewRoles(String lanId,List<RolesDto> roles) {
//Set<String> roles = Set.of("admin", "read","write");
// Set<String> roles = Set.of("opr");
Set<Role> roleSet = new HashSet<Role>();
for(RolesDto role :roles)
{
Role roleDB = roleRepo.findByRoleName(role.getRoleName());
if(roleDB ==null) {
roleDB = new Role(role.getRoleName());
roleSet.add(roleDB);
}
}
roleRepo.saveAll(roleSet);
}
@Transactional
public void addUserRole(String lanId,List<RolesDto> roles) {
//Set<String> roles = Set.of("admin", "read","write");
//Set<String> roles = Set.of("opr");
User userDB = userRepo.findByLanId(lanId);
if(userDB == null) {
userDB = new User(lanId);
for(RolesDto role : roles) {
Role roledb = roleRepo.findByRoleName(role.getRoleName());
userDB.addRole(roledb, true);
}
}
else
{
for(RolesDto role : roles) {
Role roledb = roleRepo.findByRoleName(role.getRoleName());
userDB.addRole(roledb, true);
}
}
userRepo.save(userDB);
}
}
样品输入:1:首次保存-成功
SAMPLE INPUT: 1 : Saving for first time - SUCCESS
{
"lanId":"ABC123",
"roles" :[{
"roleName" : "opr"
}
]
}
样本输入2:将其他角色保存到同一用户-失败
SAMPLE INPUT 2 : Saving additional roles to the same user - FAILURE
{
"lanId":"AB123",
"roles" :[{
"roleName" : "admin"
},{
"roleName" : "read"
},
{
"roleName" : "write"
}
]
}
异常:(试图将null插入用户和链接实体中的角色)
Exception: (Trying to insert null into user and role in link entity)
2020-09-18 11:12:34.379 DEBUG 24862 --- [nio-8080-exec-5] org.hibernate.SQL :
select
userrole0_.user_id as user_id2_2_0_,
userrole0_.role_id as role_id3_2_0_,
userrole0_.privileged as privileg1_2_0_
from
pam.user_role userrole0_
where
userrole0_.user_id=?
and userrole0_.role_id=?
2020-09-18 11:12:34.379 TRACE 24862 --- [nio-8080-exec-5] o.h.type.descriptor.sql.BasicBinder : binding parameter [1] as [BIGINT] - [1739260]
2020-09-18 11:12:34.379 TRACE 24862 --- [nio-8080-exec-5] o.h.type.descriptor.sql.BasicBinder : binding parameter [2] as [BIGINT] - [1739261]
2020-09-18 11:12:34.393 ERROR 24862 --- [nio-8080-exec-5] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.dao.DataIntegrityViolationException: A different object with the same identifier value was already associated with the session : [com.sample.m2m.repository.UserRole#UserRole(user=null, role=null, privileged=true)]; nested exception is javax.persistence.EntityExistsException: A different object with the same identifier value was already associated with the session : [com.sample.m2m.repository.UserRole#UserRole(user=null, role=null, privileged=true)]] with root cause
javax.persistence.EntityExistsException: A different object with the same identifier value was already associated with the session : [com.sample.m2m.repository.UserRole#UserRole(user=null, role=null, privileged=true)]
at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:123) ~[hibernate-core-5.4.20.Final.jar:5.4.20.Final]
at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:181) ~[hibernate-core-5.4.20.Final.jar:5.4.20.Final]
我在映射或用户实体的Utility方法中缺少某些内容吗?非常感谢您的帮助.
Am I missing something in the mapping or in the utility method of user entity . Any help is much appreciated.
推荐答案
UserRole属性不是表的主要ID，因此@Id不应位于表2上.
UserRole attributes aren’t the table’s primary ID so @Id should not be on these 2.
您应该向UserRole添加一个ID属性，并使用@Id和@GeneratedValue对其进行注释.
You should add an ID attribute to UserRole and annotate that with @Id and @GeneratedValue.
@ManyToOne将在数据库中产生外键
The @ManyToOne will result in a foreign key in the database
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