指定字段对于 MongoDB 是暂时的，但对于 RestController 不是

Question

我正在使用 spring-boot 来提供一个与 MongoDB 保持一致的 REST 接口。我正在使用 'standard' 依赖项为其提供动力，包括 spring-boot-starter-data-mongodb 和 spring-boot-starter-web.

但是，在我的某些 classes 中，我对某些字段进行了注释 @Transient，以便 MongoDB 不会保留该信息。但是，我确实希望在我的休息服务中发送这些信息。不幸的是，MongoDB 和其余控制器似乎共享该注释。因此，当我的前端接收到 JSON 对象时，这些字段不会被实例化（但仍会声明）。删除注释允许字段在 JSON 对象中出现。

如何分别配置 MongoDB 和 REST 的瞬态？

这是我的 class

package com.clashalytics.domain.building;

import com.clashalytics.domain.building.constants.BuildingConstants;
import com.clashalytics.domain.building.constants.BuildingType;
import com.google.common.base.Objects;
import org.springframework.data.annotation.Id;
import org.springframework.data.annotation.Transient;

import java.util.*;

public class Building {

    @Id
    private int id;

    private BuildingType buildingType;
    private int level;
    private Location location;
    // TODO 
    @Transient
    private int hp;
    @Transient
    private BuildingDefense defenses;

    private static Map<Building,Building> buildings = new HashMap<>();

    public Building(){}
    public Building(BuildingType buildingType, int level){
        this.buildingType = buildingType;
        this.level = level;
        if(BuildingConstants.hpMap.containsKey(buildingType))
            this.hp = BuildingConstants.hpMap.get(buildingType).get(level - 1);

        this.defenses = BuildingDefense.get(buildingType, level);
    }

    public static Building get(BuildingType townHall, int level) {
        Building newCandidate = new Building(townHall,level);
        if (buildings.containsKey(newCandidate)){
            return buildings.get(newCandidate);
        }
        buildings.put(newCandidate,newCandidate);
        return newCandidate;
    }

    public int getId() {
        return id;
    }

    public String getName(){
        return buildingType.getName();
    }

    public BuildingType getBuildingType() {
        return buildingType;
    }

    public int getHp() {
        return hp;
    }

    public int getLevel() {
        return level;
    }

    public Location getLocation() {
        return location;
    }

    public void setLocation(Location location) {
        this.location = location;
    }

    public BuildingDefense getDefenses() {
        return defenses;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Building building = (Building) o;
        return Objects.equal(id, building.id) &&
                Objects.equal(hp, building.hp) &&
                Objects.equal(level, building.level) &&
                Objects.equal(buildingType, building.buildingType) &&
                Objects.equal(defenses, building.defenses) &&
                Objects.equal(location, building.location);
    }

    @Override
    public int hashCode() {
        return Objects.hashCode(id, buildingType, hp, level, defenses, location);
    }
}

照原样，hp 和 defenses 分别显示为 0 和 null。如果我删除 @Transient 标签，它就会通过。

Answer 1

您的问题似乎是 mongo 和 jackson 的行为都符合预期。 Mongo 不会保留数据，jackson 会忽略属性，因为它被标记为瞬态。我设法让 'tricking' jackson 忽略了瞬态场，然后用 @JsonProperty 注释了 getter 方法。这是我的示例 bean。

    @Entity
    public class User {

    @Id
    private Integer id;
    @Column
    private String username;

    @JsonIgnore
    @Transient
    private String password;

    @JsonProperty("password")
    public String getPassword() {
        return // your logic here;
    }
}

这与其说是一个合适的解决方案，不如说是一种变通方法，所以我不确定这是否会给您带来任何副作用。

Answer 2

只要您使用 org.springframework.data.annotation.Transient，它就会按预期工作。 Jackson 对 spring-data 一无所知，它忽略了它的注释。

有效的示例代码：

interface PersonRepository extends CrudRepository<Person, String> {}

import org.springframework.data.annotation.Id;
import org.springframework.data.annotation.Transient;
import org.springframework.data.mongodb.core.mapping.Document;

@Document
class Person {
    @Id
    private String id;
    private String name;
    @Transient
    private Integer age;

    // setters & getters & toString()
}

@RestController
@RequestMapping("/person")
class PersonController {
    private static final Logger LOG = LoggerFactory.getLogger(PersonController.class);
    private final PersonRepository personRepository;

    @Autowired
    PersonController(PersonRepository personRepository) {
        this.personRepository = personRepository;
    }

    @RequestMapping(method = RequestMethod.POST)
    public void post(@RequestBody Person person) {
        // logging to show that json deserialization works
        LOG.info("Saving person: {}", person);
        personRepository.save(person);
    }

    @RequestMapping(method = RequestMethod.GET)
    public Iterable<Person> list() {
        Iterable<Person> list = personRepository.findAll();
        // setting age to show that json serialization works
        list.forEach(foobar -> foobar.setAge(18));

        return list;
    }
}

正在执行 POST http://localhost:8080/person:

{
    "name":"John Doe",
    "age": 40
}

日志输出Saving person: Person{age=40, id='null', name='John Doe'}
person 集合中的条目： { "_id" : ObjectId("55886dae5ca42c52f22a9af3"), "_class" : "demo.Person", "name" : "John Doe" } - 年龄不持久化

正在执行 GET http://localhost:8080/person:

结果：[{"id":"55886dae5ca42c52f22a9af3","name":"John Doe","age":18}]

Answer 3

carlos-bribiescas, 你用的是什么版本。可能是版本问题。因为此临时注释仅用于不持久保存到 mongo 数据库。请尝试更改 version.Probably 类似于 Maciej one（1.2.4 版本）

其中一个版本中 json 对 spring 数据项目的解析存在问题。 http://www.widecodes.com/CyVjgkqPXX/fields-with-jsonproperty-are-ignored-on-deserialization-in-spring-boot-spring-data-rest.html

Answer 4

因为您没有将 MongoRepositories 公开为 restful 端点 Spring Data REST it makes more sense to have your Resources/endpoint responses decoupled from your domain model, that way your domain model could evolve without impacting your rest clients/consumers. For the Resource you could consider leveraging what Spring HATEOAS 必须提供。

Answer 5

我用@JsonSerialize解决了。您也可以选择 @JsonDeserialize 如果您希望它也被反序列化。

@Entity
public class Article {

@Column(name = "title")
private String title;

@Transient
@JsonSerialize
@JsonDeserialize
private Boolean testing;
}

// No annotations needed here
public Boolean getTesting() {
    return testing;
}

public void setTesting(Boolean testing) {
    this.testing = testing;
}

Answer 6

我通过实现自定义 JacksonAnnotationIntrospector:

解决了这个问题

@Bean
@Primary
ObjectMapper objectMapper() {
  Jackson2ObjectMapperBuilder builder = new Jackson2ObjectMapperBuilder();
  AnnotationIntrospector annotationIntrospector = new JacksonAnnotationIntrospector() {
    @Override
    protected boolean _isIgnorable(Annotated a) {
      boolean ignorable = super._isIgnorable(a);
      if (ignorable) {
        Transient aTransient = a.getAnnotation(Transient.class);
        JsonIgnore jsonIgnore = a.getAnnotation(JsonIgnore.class);

        return aTransient == null || jsonIgnore != null && jsonIgnore.value();
      }
      return false;
    }
  };
  builder.annotationIntrospector(annotationIntrospector);
  return builder.build();
}

此代码使 Jackson 的 org.springframework.data.annotation.Transient 注释不可见，但它适用于 mongodb。

Answer 7

您可以在字段中使用注释 org.bson.codecs.pojo.annotations.BsonIgnore 而不是 @transient，这样 MongoDB 将不会持续存在。

@BsonIgnore
private BuildingDefense defenses;

它也适用于吸气剂。

指定字段对于 MongoDB 是暂时的，但对于 RestController 不是

Specify field is transient for MongoDB but not for RestController

java

rest

spring

mongodb

spring-boot