Spring REST JSON serialization/deserialization 复合多态类型

Question

我使用 Spring/Spring Boot 和 Spring MVC with @RestController

我有一个复合模型对象：

public abstract class BaseQuery {

    private final Long characteristicId;

...

}

public abstract class ComparableQuery extends BaseQuery {

    private final Object value;

    private final String comparisonOperator;

...

}

public class GreaterOrEqualQuery extends ComparableQuery {

    public GreaterOrEqualQuery(Long characteristicId, Object value) {
        super(characteristicId, value, ">=");
    }

}

public class EqualQuery extends ComparableQuery {

    public EqualQuery(Long characteristicId, Object value) {
        super(characteristicId, value, "=");
    }

}

public class GreaterQuery extends ComparableQuery {

    public GreaterQuery(Long characteristicId, Object value) {
        super(characteristicId, value, ">");
    }

}

public class CompositQuery extends BaseQuery {

    private final String operator;
    private final BaseQuery[] queries;

    public CompositQuery(Long characteristicId, Operator operator, BaseQuery... queries) {
        super(characteristicId);
        this.operator = operator.value;
        this.queries = queries;
    }

...

}

等等

此模型的示例用法如下所示：

Set<BaseQuery> queries = new HashSet<>();

BaseQuery megapixelCharacteristicQuery = new CompositQuery(megapixelCharacteristic.getCharacteristicId(), CompositQuery.Operator.AND, new GreaterOrEqualQuery(megapixelCharacteristic.getCharacteristicId(), 10), new LessOrEqualQuery(megapixelCharacteristic.getCharacteristicId(), 50));
queries.add(megapixelCharacteristicQuery);
queries.add(new EqualQuery(androidCharacteristic.getCharacteristicId(), true));

Set<BaseQuery> queries 的序列化 JSON 对象看起来像：

[
   {
      "operator":"AND",
      "queries":[
         {
            "value":10,
            "comparisonOperator":"\u003e\u003d",
            "characteristicId":391
         },
         {
            "value":50,
            "comparisonOperator":"\u003c\u003d",
            "characteristicId":391
         }
      ],
      "characteristicId":391
   },
   {
      "value":true,
      "comparisonOperator":"\u003d",
      "characteristicId":383
   }
]

我必须将此或类似的 JSON 从客户端应用程序 (AngularJS) 传递到我的后端 REST API 端点，以便获得如上所述的正确反序列化模型（设置使用适当的条目，例如 CompositQuery 或 EqualQuery).

现在，我的 Rest 控制器中的 Spring 应用程序后端逻辑无法使用适当的类.

正确反序列化此 JSON

Spring 中是否有任何方法可以为此 JSON 提供一些元信息（或其他信息）以帮助 Spring 正确反序列化此结构？

Answer 1

您可以在超类上使用 jackson 注释来实现此目的，如下所示：

import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonSubTypes;
import com.fasterxml.jackson.annotation.JsonSubTypes.Type;
import com.fasterxml.jackson.annotation.JsonTypeInfo;

@JsonTypeInfo(use = JsonTypeInfo.Id.CLASS, include = JsonTypeInfo.As.PROPERTY, property = "javaclass")
@JsonSubTypes({
    @Type(value = GreaterOrEqualQuery.class),
    @Type(value = EqualQuery.class)
    //and so on...
})
public abstract class BaseQuery {
    ...
}

这会将 javaclass 属性添加到 json 表示中，这是 use = JsonTypeInfo.Id.CLASS 情况下的完全限定名称。为了简化此属性的值，请考虑 @JsonTypeInfo 的 use 参数的不同选项（例如 JsonTypeInfo.Id.NAME）。

Spring REST JSON serialization/deserialization 复合多态类型

Spring REST JSON serialization/deserialization of composite polymorphic types

java

spring

json

jackson

spring-restcontroller