使用mongoTemplate在嵌入式文檔字段上進行MongoDB投影

Question

在我的Java應用程序中，我想檢索嵌入式文檔的字段。 這是我的pojo：

我的User.class

public class User implements Comparable<User> {

    @Id
    private String username;

    private String ownerFirstname;

    private String ownerLastname;

    @DBRef
    @CascadeSave
    @JsonInclude(JsonInclude.Include.NON_NULL)
    private Role role;
}

Role.class

@Document
@JsonDeserialize(using = RoleDeserializer.class)
public interface Role {

    String getId();

    void setId(String id);

}

Society.class

@Document(collection = "role")
public class Society implements Role {

    @Id
    private String id;

    private String name;

    @JsonInclude(JsonInclude.Include.NON_NULL)
    private Address societyAddress;

    @JsonInclude(JsonInclude.Include.NON_NULL)
    private String vatNumber;

    @JsonInclude(JsonInclude.Include.NON_NULL)
    private long birthday;

    private List<ProductResearch> productResearches;

    @DBRef
    private List<Advertisement> advertisementOwnedList;

    @DBRef
    private List<OrderRequest> orderRequests;

    private UserType type;
}

我對adsOwnedList字段感興趣，但我無法獲取它。 我嘗試使用MongoTemplate進行投影：

Query query = Query.query(Criteria.where("_id").is(user.getUsername()));
query.fields().include("role.advertisementOwnedList;");
User user1 = mongoTemplate.findOne(query, User.class);

或使用MongoRepository：

@Query(value = "{ '_id' : ?0}", fields = "{ '_id': 0 , 'role' : 1 ,
'role.advertisementOwnedList' : 1 }") 
User getRoleAdvertisementOwnedList(String username);

但是角色是一個接口，我總​​是會遇到異常：

org.springframework.data.mapping.model.MappingInstantiationException: Failed to instantiate it.bmv.backend.model.Role using constructor NO_CONSTRUCTOR with arguments 

    at org.springframework.data.convert.ReflectionEntityInstantiator.createInstance(ReflectionEntityInstantiator.java:64)
    at org.springframework.data.convert.ClassGeneratingEntityInstantiator.createInstance(ClassGeneratingEntityInstantiator.java:83)
    at org.springframework.data.mongodb.core.convert.MappingMongoConverter.read(MappingMongoConverter.java:259)
    at org.springframework.data.mongodb.core.convert.MappingMongoConverter.read(MappingMongoConverter.java:239)
    at org.springframework.data.mongodb.core.convert.MappingMongoConverter.readValue(MappingMongoConverter.java:1222)
    at org.springframework.data.mongodb.core.convert.MappingMongoConverter.access$200(MappingMongoConverter.java:85)
    at org.springframework.data.mongodb.core.convert.MappingMongoConverter$MongoDbPropertyValueProvider.getPropertyValue(MappingMongoConverter.java:1170)
    at org.springframework.data.mongodb.core.convert.MappingMongoConverter.getValueInternal(MappingMongoConverter.java:880)
    at org.springframework.data.mongodb.core.convert.DefaultDbRefResolverCallback.resolve(DefaultDbRefResolverCallback.java:59)
    at org.springframework.data.mongodb.core.convert.DefaultDbRefResolver.resolveDbRef(DefaultDbRefResolver.java:98)
    at org.springframework.data.mongodb.core.convert.MappingMongoConverter$2.doWithAssociation(MappingMongoConverter.java:313)
    at org.springframework.data.mapping.model.BasicPersistentEntity.doWithAssociations(BasicPersistentEntity.java:360)
    at org.springframework.data.mongodb.core.convert.MappingMongoConverter.read(MappingMongoConverter.java:296)
    at org.springframework.data.mongodb.core.convert.MappingMongoConverter.read(MappingMongoConverter.java:239)
    at org.springframework.data.mongodb.core.convert.MappingMongoConverter.read(MappingMongoConverter.java:199)
    at org.springframework.data.mongodb.core.convert.MappingMongoConverter.read(MappingMongoConverter.java:195)
    at org.springframework.data.mongodb.core.convert.MappingMongoConverter.read(MappingMongoConverter.java:85)
    at org.springframework.data.mongodb.core.MongoTemplate$ReadDbObjectCallback.doWith(MongoTemplate.java:2324)
    at org.springframework.data.mongodb.core.MongoTemplate.executeFindOneInternal(MongoTemplate.java:1925)
    at org.springframework.data.mongodb.core.MongoTemplate.doFindOne(MongoTemplate.java:1736)
    at org.springframework.data.mongodb.core.MongoTemplate.findOne(MongoTemplate.java:606)
    at org.springframework.data.mongodb.core.MongoTemplate.findOne(MongoTemplate.java:601)
    at it.bmv.backend.UserTest.getAdvTest(UserTest.java:93)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
    at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
    at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:252)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:94)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:191)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
    at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:51)
    at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:237)
    at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [it.bmv.backend.model.Role]: Specified class is an interface
    at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:99)
    at org.springframework.data.convert.ReflectionEntityInstantiator.createInstance(ReflectionEntityInstantiator.java:61)
    ... 50 more

如何獲得角色嵌套文檔的字段？

Answer 1

由於我的評論可能不夠清楚，我將嘗試給出更詳盡的答案。

對於內部測試工具，如果有時間我要寫，我想出了包含一個或多個不同場景的任務的想法。 場景只是需要執行的某個預定義測試。 任務還包含測試用例列表，其中包含相應測試的當前狀態。

我們簡化的模型如下所示：

@Getter
@Setter
@Document(collection = "task")
public class TaskEntity implements Serializable, NamedResource {

  @Id
  private String id;
  private String name;
  private String testerName;
  ...
  @DBRef
  private List<ScenarioEntity> testsToExecute = new ArrayList<>();
  ...
  private List<TestCase> performedTests = new ArrayList<>();
  ...
}

方案實體保存在不同的集合中，並且僅可在任務條目中用作參考。 但是，測試用例是任務中的嵌入式文檔。

Spring Data允許通過引入一個單獨的接口來定義實體或子文檔的視圖，該接口包含您感興趣的實體getter方法的子集。

在示例中， TaskView包含以下內容：

public interface TaskView extends NamedResource {

  String getTesterName();

  @Value("#{target.testsToExecute}")
  List<ScenarioView> getTestsToExecute();
}

ScenarioView如下所示：

public interface ScenarioView extends NamedResource {

}

因為它僅繼承了NamedResource的方法：

public interface NamedResource {
  String getId();
  String getName();
}

另一方面， TestCaseView稍微復雜一點，因為它還從包含的條目中檢索屬性：

public interface TestCaseView {

  String getId();
  String getTaskId();
  Date getStart();
  Date getEnd();
  @Value("#{target.scenario.id}")
  String getScenarioId();
  @Value("#{target.secnario.name}")
  String getScenarioName();
  @Value("#{target.result.result.name()}")
  String getJobResult();
}

為了利用所有這些接口， TaskRepository確實定義了以下查詢：

public interface TaskRepository extends MongoRepository<TaskEntity, String> {

  @Query("{ '_id': ?0 }")
  TaskEntity findById(String id);

  @Query("{ }")
  Page<TaskView> findPageable(Pageable pageable);

  @Query("{ '_id': ?0, 'performedTests': { 'id': ?1 } }")
  TestCase findTestCaseByIdViaTaskId(String id, String uuid);

  @Query("{ '_id': ?0, 'performedTests': { } }")
  List<TestCase> findTestsCasesForTask(String id);

  @Query("{ '_id': ?0, 'performedTests': { } }")
  Page<TestCaseView> findTestCaseViews(String id, Pageable pageable);

  ...
}

從代碼中可以看到，Spring Data允許直接在存儲庫接口中定義視圖接口，而不是實體類，從而僅檢索數據的子集或集合。