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我一直在使用Morphia，因为我在使用Spring Data for Mongodb的参考文档时遇到了问题。下面是我拥有的数据和代码的快照...使用Morphia检索引用的文档会返回奇怪的错误
这里是我的用户和组班（getter和setter方法省略）
用户类别
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import org.mongodb.morphia.annotations.Entity;
import org.mongodb.morphia.annotations.Id;
import org.mongodb.morphia.annotations.Reference;
@Entity(value="users")
public class User {
@Id
private String id;
private String username;
private String firstname;
private String lastname;
private String email;
private long cellnumber;
private Date datejoined;
private boolean active;
private Account account;
@Reference(value="usergroups", lazy=true)
private List<Group> usergroups = new ArrayList<>();
}
的组类。
@Entity(value="groups")
public class Group {
@Id
private String id;
private String name;
private String description;
private long creationdate;
@Reference
private User user;
}
我现在正在主要方法中运行以下方法，名为scenario1（）和scenario2（）。
private void scenario1() {
User newUser = setupUser(new User());
datastore.save(newUser);
Query<User> query = datastore.createQuery(User.class)
.field("firstname").equal("Jome");
User user = query.get();
Account account = new Account();
account.setBalance(0.0);
account.setSmsvalue(0.18);
UpdateOperations<User> update = datastore
.createUpdateOperations(User.class);
update.set("account", account);
user.setAccount(account);
datastore.save(user);
List<Group> groups = query.get().getUsergroups();
Group group1 = new Group();
group1.setCreationdate(new Date().getTime());
group1.setDescription("test group for first user");
group1.setName("Group One");
group1.setUser(query.get());
datastore.save(group1);
groups.add(group1);
update.add("usergroups", group1);
datastore.update(query, update);
Group group2 = new Group();
group2.setCreationdate(new Date().getTime());
group2.setDescription("Another test group for first user");
group2.setName("Group Two");
group2.setUser(query.get());
datastore.save(group2);
groups.add(group2);
update.add("usergroups", group2);
datastore.update(query, update);
System.out.println(user);
List<Group> savedgroups = user.getUsergroups();
System.out.println(savedgroups);
}
这是低于输出
User [id=52e8894ef148a7f866b9f1ac, username=jomski2013, firstname=Jome, lastname=Akpoduado, [email protected], cellnumber=123456789]
[Group [id=52e8894ef148a7f866b9f1ad, name=Group One, description=test group for first user, creationdate=1390971214880, owner=User [id=52e8894ef148a7f866b9f1ac, username=jomski2013, firstname=Jome, lastname=Akpoduado, [email protected], cellnumber=123456789]], Group [id=52e8894ef148a7f866b9f1ae, name=Group Two, description=Another test group for first user, creationdate=1390971214884, owner=User [id=52e8894ef148a7f866b9f1ac, username=jomski2013, firstname=Jome, lastname=Akpoduado, [email protected], cellnumber=123456789]]]
并从蒙戈控制台视图
> db.users.find().pretty()
{
"_id" : ObjectId("52e8894ef148a7f866b9f1ac"),
"account" : {
"balance" : 0,
"smsvalue" : 0.18
},
"active" : true,
"cellnumber" : NumberLong("123456789"),
"className" : "org.imanmobile.sms.core.domain.User",
"datejoined" : ISODate("2014-01-29T04:53:34.746Z"),
"email" : "[email protected]",
"firstname" : "Jome",
"lastname" : "Akpoduado",
"password" : "$2a$10$c0SAy7eJZv06eqmAWQNUP.YrXtB7tDOdi11lkZqlAVgzVGU9RCbCS",
"usergroups" : [
DBRef("groups", "52e8894ef148a7f866b9f1ad"),
DBRef("groups", "52e8894ef148a7f866b9f1ae")
],
"username" : "jomski2013"
}
> db.groups.find().pretty()
{
"_id" : ObjectId("52e8894ef148a7f866b9f1ad"),
"className" : "org.imanmobile.sms.core.domain.Group",
"name" : "Group One",
"description" : "test group for first user",
"creationdate" : NumberLong("1390971214880"),
"user" : DBRef("users", "52e8894ef148a7f866b9f1ac")
}
{
"_id" : ObjectId("52e8894ef148a7f866b9f1ae"),
"className" : "org.imanmobile.sms.core.domain.Group",
"name" : "Group Two",
"description" : "Another test group for first user",
"creationdate" : NumberLong("1390971214884"),
"user" : DBRef("users", "52e8894ef148a7f866b9f1ac")
}
然而，当我随后运行scenario2（）
private void scenario2() {
Query<User> query = datastore.createQuery(User.class);
User user = query.field("username").equal("jomski2013").get();
System.out.println("Number of groups: " + user.getUsergroups().size());
}
我得到错误...
Caused by: org.mongodb.morphia.mapping.MappingException: The reference({ "$ref" : "groups", "$id" : "52e8894ef148a7f866b9f1ad" }) could not be fetched for org.imanmobile.sms.core.domain.User.usergroups
at org.mongodb.morphia.mapping.ReferenceMapper.resolveObject(ReferenceMapper.java:304)
at org.mongodb.morphia.mapping.ReferenceMapper$1.eval(ReferenceMapper.java:243)
at org.mongodb.morphia.utils.IterHelper.loopOrSingle(IterHelper.java:89)
at org.mongodb.morphia.mapping.ReferenceMapper.readCollection(ReferenceMapper.java:239)
at org.mongodb.morphia.mapping.ReferenceMapper.fromDBObject(ReferenceMapper.java:163)
at org.mongodb.morphia.mapping.Mapper.readMappedField(Mapper.java:602)
at org.mongodb.morphia.mapping.Mapper.fromDb(Mapper.java:584)
at org.mongodb.morphia.mapping.Mapper.fromDBObject(Mapper.java:294)
at org.mongodb.morphia.query.MorphiaIterator.convertItem(MorphiaIterator.java:71)
at org.mongodb.morphia.query.MorphiaIterator.processItem(MorphiaIterator.java:58)
at org.mongodb.morphia.query.MorphiaIterator.next(MorphiaIterator.java:53)
at org.mongodb.morphia.query.QueryImpl.get(QueryImpl.java:408)
at org.imanmobile.sms.PlayClass.scenario2(PlayClass.java:35)
at org.imanmobile.sms.PlayClass.run(PlayClass.java:29)
at org.springframework.boot.SpringApplication.runCommandLineRunners(SpringApplication.java:644)
我的问题是，为什么是吗啡能够获取该是围绕保存第一次组，但随后不进行？有什么不同，或者我真的应该寻找什么或缺少什么？
我仍然遇到同样的问题。我编辑了原始问题并添加了更多代码。奇怪的是，当我运行名为scenario1（）的方法时，我得到了代码后面的结果。运行该方法，scenario2（）仍然会给出我最初讨论的参考错误。 – Jome
好吧，我最终做的是将User和Group类的id设置为ObjectId'private ObjectId id;'这似乎解决了问题。不过，我的印象是ID可以是String，int，Long等吗？ Morphia没有意识到这一点？ 投票这个答案反正...... :) – Jome
你的发现显示_id属性作为ObjectId，但你的代码显示他们作为字符串。你的收藏中是否有混合数据？作为ID的字符串非常好。 – evanchooly