Question

我有一个表单，此表单需要更新我的记录，但显然没有更新，我收到以下错误消息。在4天内处理此异常，我决定提问。如果您需要额外的信息，我可以添加一些。

JSP异常;

MergeContext#attempt to create managed -> managed mapping with different entities: [main.model.Users#1]; [main.model.Users#1]; nested exception is java.lang.IllegalStateException: MergeContext#attempt to create managed -> managed mapping with different entities: [main.model.Users#1]; [main.model.Users#1]

Java异常;

java.lang.IllegalStateException: MergeContext#attempt to create managed -> managed mapping with different entities: [main.model.Users#1]; [main.model.Users#1]

控制器;它从表单获取位置用户和域信息并将其保存到DB;

@PostMapping("/save-personel-info")
public String savePersonelInfo(@RequestParam int id, HttpServletRequest request, @ModelAttribute("Users") Users users, @ModelAttribute("Positions") Positions positions, @ModelAttribute("Domains") Domains domains, ModelMap model){
    usersService.save(users);
    request.setAttribute("mode", "MODE_USERS");
    return "redirect:/index";
}

服务;

@Service
@Transactional
public class UsersService {

    public void save(Users users){
        usersRepository.save(users);
    }
}

表;

<form:form method="POST" action="/save-personel-info" modelAttribute="Users">
    <tr>
        <form:input id="1-1-0" type="hidden" class="form-control" path="id"/>
            <td><form:input id="1-1-0" type="text" class="form-control" path="username" /></td>
            <td><form:input id="1-1-0" type="text" class="form-control" path="mail" /></td>
        <td>
            <form:select path="Positions" class="form-control">
                <form:options items="${Pst}"  itemValue="id" itemLabel="position_name" />
            </form:select> 
        </td>                                   
        <td>
            <form:select path="Domains" class="form-control">
                <form:options items="${Domains}"  itemValue="id" itemLabel="domain_name" />
            </form:select> 
        </td>
    </tr>
    <input type="submit" value="Submit" />
</form:form>

用户类;

@Component
@Entity
public class Users {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    public long id;
    public String username;
    public String mail;

    @Temporal(TemporalType.DATE)
    public Date enrolment_date;

    @ManyToOne(cascade = CascadeType.ALL)
    public Domains domains;

    @ManyToOne(cascade = CascadeType.ALL)
    public Positions positions;

    @OneToMany(targetEntity = UserLanguages.class, mappedBy = "users", cascade = CascadeType.ALL, fetch = FetchType.EAGER)
    public Set<UserLanguages> userlanguages = new HashSet<UserLanguages>();

    @OneToMany(targetEntity = UserCertificates.class, mappedBy = "users", cascade = CascadeType.ALL, fetch = FetchType.EAGER)
    public Set<UserCertificates> usercertificates = new HashSet<UserCertificates>();

    @OneToMany(targetEntity = UserKnowledge.class, mappedBy = "users", cascade = CascadeType.ALL, fetch = FetchType.EAGER)
    public Set<UserKnowledge> userknowledge = new HashSet<UserKnowledge>();

＆＃34;与不同实体的托管映射是什么意思＆＃34;我研究这个错误消息，但我想没有人得到这个错误。 Hibernate-orm

Answer 1

此错误消息表明Hibernate已检测到无效的管理实体＆＃39; - ＆GT; ＆＃39;管理实体＆＃39;映射键！=值。

MergeContext存储托管实体到合并实体的映射（反之亦然），我猜你有两个不同的托管实体同时加载，表示数据库中的相同记录（＆＃39;为什么你会得到这个错误）。 ^{（来源：internal source code of Hibernate Core分析）}

从提供的示例中很难说另一个Users实体。所以我在这里写了一些想法：

Users实体可以在Domains，Positions，UserLanguages，UserCertificates或UserKnowledge类中定义。如果您使用CascadeType.ALL / CascadeType.PERSIST找到它，请删除cascade属性。

如果某个地方您正在使用集合中的Users个实体并尝试保留它，则可能还会遇到此错误。覆盖equals()类的hashCode()和Users方法，并使用Set来确保对象的唯一性。 equals()方法可能与比较ID一样简单：

@Override
public boolean equals(Object o) {
    if (this == o) {
        return true;
    }
    if (o == null || getClass() != o.getClass()) {
        return false;
    }

    Users that = (Users) o;

    return getId() == that.getId();
}

@Override
public int hashCode() {
    return Long.valueOf(getId()).hashCode();
}

仔细查看程序中的其他Users个实体，然后session.evict(users)从会话缓存中删除对象实例。

Answer 2

有时它只是Hibernate中的一个错误：

https://hibernate.atlassian.net/browse/HHH-12439?attachmentViewMode=gallery

说明
根据实体的初始化顺序级联合并失败，并出现IllegalStateException，如：

08:26:15,502 ERROR [org.jboss.as.ejb3.invocation] (default task-1) WFLYEJB0034: 
EJB Invocation failed on component Bean for method public abstract void 
org.jboss.playground.BeanRemote.errorTest(java.lang.Long,java.lang.String):
javax.ejb.EJBException: java.lang.IllegalStateException:  
MergeContext#attempt to create managed -> managed mapping with different entities:    
[org.jboss.playground.Frd#9]; [org.jboss.playground.Frd#9]

...

JPA管理的映射具有不同的实体错误

2 个答案: