在聚合中使用展开操作时，我遇到映射结果的问题。
以下是我的依赖项。在依赖项下面我提到了两个模型类，我在最后使用聚合代码。我在本机查询以及Spring查询中获取结果中的数据。但不同的是，Spring查询结果即使有文件，orgMap数组也是空的。而本机查询返回的文档对orgMap数组中的每个文档都有一个数据。
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>4.3.7.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>4.3.7.RELEASE</version>
</dependency>
<!-- mongodb java driver -->
<dependency>
<groupId>org.mongodb</groupId>
<artifactId>mongo-java-driver</artifactId>
<version>3.0.0</version>
</dependency>
<!-- Spring data mongodb -->
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-mongodb</artifactId>
<version>1.10.3.RELEASE</version>
</dependency>
package com.mongodb.model.user;
import java.util.HashSet;
import org.springframework.data.annotation.Id;
import org.springframework.data.annotation.PersistenceConstructor;
import org.springframework.data.mongodb.core.mapping.Document;
import com.alta.mongodb.model.user.UserOrgMap;
@Document(collection = "users")
public class Users {
public Users() {
super();
}
@PersistenceConstructor
public Users(String userId, String login, String firstName, String lastName,
HashSet<UserOrg> userOrg) {
super();
this.userId = userId;
this.login = login;
this.firstName = firstName;
this.lastName = lastName;
this.userOrgMap = userOrgMap;
}
@Id
private String userId;
private String login;
private String firstName;
private String lastName;
private HashSet<UserOrgMap> userOrgMap;
public String getUserId() {
return userId;
}
public void setUserId(String userId) {
this.userId = userId;
}
public String getLogin() {
return login;
}
public void setLogin(String login) {
this.login = login;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public HashSet<UserOrgMap> getUserOrgMap() {
return userOrgMap;
}
public void setUserOrgMap(HashSet<UserOrgMap> userOrgMap) {
this.userOrgMap = userOrgMap;
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((firstName == null) ? 0 : firstName.hashCode());
result = prime * result + ((lastName == null) ? 0 : lastName.hashCode());
result = prime * result + ((login == null) ? 0 : login.hashCode());
result = prime * result + ((userId == null) ? 0 : userId.hashCode());
result = prime * result + ((userOrgMap == null) ? 0 : userOrgMap.hashCode());
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
Users other = (Users) obj;
if (firstName == null) {
if (other.firstName != null)
return false;
} else if (!firstName.equals(other.firstName))
return false;
if (lastName == null) {
if (other.lastName != null)
return false;
} else if (!lastName.equals(other.lastName))
return false;
if (login == null) {
if (other.login != null)
return false;
} else if (!login.equals(other.login))
return false;
if (userId == null) {
if (other.userId != null)
return false;
} else if (!userId.equals(other.userId))
return false;
if (userOrgMap == null) {
if (other.userOrgMap != null)
return false;
} else if (!userOrgMap.equals(other.userOrgMap))
return false;
return true;
}
@Override
public String toString() {
return "Users [userId=" + userId + ", login=" + login + ", firstName=" + firstName + ", lastName=" + lastName
+ ", userOrgMap=" + userOrgMap + "]";
}
}
package com.mongodb.model.user;
import org.springframework.data.annotation.PersistenceConstructor;
public class UserOrg {
private String orgId;
private String createdbyuser;
public UserOrg() {
super();
}
public UserOrg(String orgId, String createdbyuser) {
super();
this.orgId = orgId;
this.createdbyuser = createdbyuser;
}
public String getOrgId() {
return orgId;
}
public void setOrgId(String orgId) {
this.orgId = orgId;
}
public String getCreatedbyuser() {
return createdbyuser;
}
public void setCreatedbyuser(String createdbyuser) {
this.createdbyuser = createdbyuser;
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((createdbyuser == null) ? 0 : createdbyuser.hashCode());
result = prime * result + ((orgId == null) ? 0 : orgId.hashCode());
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
UserOrg other = (UserOrg) obj;
if (createdbyuser == null) {
if (other.createdbyuser != null)
return false;
} else if (!createdbyuser.equals(other.createdbyuser))
return false;
if (orgId == null) {
if (other.orgId != null)
return false;
} else if (!orgId.equals(other.orgId))
return false;
return true;
}
@Override
public String toString() {
return "UserOrg [orgId=" + orgId + ", createdbyuser=" + createdbyuser + "]";
}
}
Aggregation aggregation = newAggregation(
unwind("userOrgMap")
);
AggregationResults<User> groupResults = mongoOperation.aggregate(aggregation,"users", User.class);
System.out.println(" groupResults raw result "+groupResults.getRawResults().get("result"));
List<User> result = groupResults.getMappedResults();
System.out.println(" result "+result);
Output :
groupResults raw result
[ { "_id" : "user_1" , "login" : "123" , "firstName" : "abc" , "lastName" : "xyz" , "userOrgMap" : { "orgId" : "org_1" , "createdbyuser" : "user_2" } ,
{ "_id" : "user_2" , "login" : "789" , "firstName" : "qqq" , "lastName" : "aaa" , "userOrgMap" : { "orgId" : "org_1" , "createdbyuser" : "user_3" }
]
result
[
User [userId=user_1, login=123, firstName=abc, lastName=xyz, userOrgMap=[] ],
User [userId=user_2, login=789, firstName=qqq, lastName=aaa, userOrgMap=[],]
]
I want to know why userOrgMap array is empty instead of having value similar to the output shown for raw results.
答案 0 :(得分：0)
userOrgMap不是原始结果中的数组，而只是单个文档。
你必须有两个选择。
在userOrgMap模型中添加额外字段userOrgMapSingle User，并在汇总查询中将unwind别名添加为userOrgMapSingle。
或
添加project阶段，将单个文档转换为具有单个文档的数组，以将其映射到现有的userOrgMap集合类型。
像
这样的东西{$project:{userOrgMap:["$userOrgMap"]}}
Spring Mongo Data Equivalent
Aggregation aggregation = newAggregation(
unwind("userOrgMap"),
new AggregationOperation() {
@Override
public DBObject toDBObject(AggregationOperationContext aggregationOperationContext) {
return new BasicDBObject("$addFields", new BasicDBObject("userOrgMap", Arrays.asList("$userOrgMap")));
}
}
);