@Document(collection = "test_person")
public class Person {
 private String name;
 @DBRef
 private EmailAddress emailAddress;
 ... getter setter 方法
}

@Document(collection = "test_email")
public class EmailAddress {
 @Id
 private String id;
 private String value;
 ... getter setter 方法
}

public Person test() {
 Person person = new Person();
 person.setName("test");
 EmailAddress emailAddress = new EmailAddress();
 emailAddress.setId("5a05108d4dcc5dece03c9e69");
 person.setEmailAddress(emailAddress);
 testRepository.save(person);
 return person;
}

public Person test() {
 Person person = new Person();
 person.setName("test");
 EmailAddress emailAddress = new EmailAddress();
 emailAddress.setName("afafa");
 person.setEmailAddress(emailAddress);
 testRepository.save(person);
 return person;
}

/**
 * MongoDB级联控制
 * Created by guanzhenxing on 2017/11/9.
 */
public class CascadeControlMongoEventListener extends AbstractMongoEventListener<Object> {
 @Autowired
 private MongoOperations mongoOperations;
 @Override
 public void onAfterSave(AfterSaveEvent<Object> event) {
 super.onAfterSave(event);
 Object source = event.getSource();
 ReflectionUtils.doWithFields(source.getClass(), new CascadeAfterSaveCallback(source, mongoOperations));
 }
 @Override
 public void onBeforeConvert(BeforeConvertEvent<Object> event) {
 super.onBeforeConvert(event);
 Object source = event.getSource();
 ReflectionUtils.doWithFields(source.getClass(), new CascadeBeforeConvertCallback(source, mongoOperations));
 }
}

/**
 * 级联控制的回调
 * Created by guanzhenxing on 2017/11/10.
 */
public class CascadeAfterSaveCallback implements ReflectionUtils.FieldCallback {
 private Object source;
 private MongoOperations mongoOperations;
 public CascadeAfterSaveCallback(final Object source, final MongoOperations mongoOperations) {
  this.source = source;
  this.mongoOperations = mongoOperations;
 }
 @Override
 public void doWith(final Field field) throws IllegalArgumentException, IllegalAccessException {
  ReflectionUtils.makeAccessible(field);
  if (field.isAnnotationPresent(DBRef.class)) {
   final Object fieldValue = field.get(source); //获得值
   if (fieldValue != null) {
    doCascadeLoad(field);
   }
  }
 }
 /**
  * 级联查询
  *
  * @param field
  */
 private void doCascadeLoad(Field field) throws IllegalAccessException {
  Object fieldValue = field.get(source);
  List<Field> idFields = ReflectionUtil.getAnnotationField(fieldValue, Id.class); //该方法是为了获得所有的被@Id注解的属性
  if (idFields.size() == 1) { //只处理一个Id
   Object idValue = ReflectionUtil.getFieldValue(fieldValue, idFields.get(0).getName());
   Object value = mongoOperations.findById(idValue, fieldValue.getClass()); //查询获得值
   ReflectionUtil.setFieldValue(source, field.getName(), value);
  }
 }
}

public class CascadeBeforeConvertCallback implements ReflectionUtils.FieldCallback {
 private Object source;
 private MongoOperations mongoOperations;
 public CascadeBeforeConvertCallback(Object source, MongoOperations mongoOperations) {
  this.source = source;
  this.mongoOperations = mongoOperations;
 }
 @Override
 public void doWith(Field field) throws IllegalArgumentException, IllegalAccessException {
  ReflectionUtils.makeAccessible(field);
  if (field.isAnnotationPresent(DBRef.class)) {
   final Object fieldValue = field.get(source); //获得值
   if (fieldValue != null) {
    doCascadeSave(field);
   }
  }
 }
 /**
  * 级联保存
  *
  * @param field
  * @throws IllegalAccessException
  */
 private void doCascadeSave(Field field) throws IllegalAccessException {
  if (field.isAnnotationPresent(CascadeSave.class)) { //如果有标识@CascadeSave注解
   Object fieldValue = field.get(source);
   List<Field> idFields = ReflectionUtil.getAnnotationField(fieldValue, Id.class);
   if (idFields.size() == 1) {
    mongoOperations.save(fieldValue);
   }
  }
 }
}

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.FIELD)
public @interface CascadeSave {
}

@Configuration
public class MongoConfig {
 @Bean
 public CascadeControlMongoEventListener userCascadingMongoEventListener() {
  return new CascadeControlMongoEventListener();
 }
}