Java Json与jackson的动态反序列化

我已经看过问题“”，但它并没有真正回答我的问题

我想反序列化如下内容：

public class Response<T> {
    private String status;
    private Error error;
    private T data;
}

或

我希望将我的响应对象一般化如下：

public class UserResponse extends Response<User> {}

最后，我创建了一个自定义反序列化程序。它可以工作，但我不满意：

public class ResponseDeserializer extends JsonDeserializer<Response> {
@Override
public Response deserialize(JsonParser jp, DeserializationContext ctxt) throws IOException {
    ObjectMapper mapper = new ObjectMapper();
    Response responseData = new Response();
    Object data = null;

    for (; jp.getCurrentToken() != JsonToken.END_OBJECT; jp.nextToken()) {
        String propName = jp.getCurrentName();
        // Skip field name:
        jp.nextToken();

        if ("contract".equals(propName)) {
            data = mapper.readValue(jp, Contract.class);
        } else if ("user".equals(propName)) {
            data = mapper.readValue(jp, User.class);
        } else if ("status".equals(propName)) {
            responseData.setStatus(jp.getText());
        } else if ("error".equals(propName)) {
            responseData.setError(mapper.readValue(jp, com.ingdirect.dg.business.object.community.api.common.Error.class));
        }
    }

    if (data instanceof Contract) {
        Response<Contract> response = new Response<Ranking>(responseData);
        return response;
    }

    if (data instanceof User) {
        Response<User> response = new Response<User>(responseData);
        return response;
    }

    // in all other cases, the type is not yet managed, add it when needed
    throw new JsonParseException("Cannot parse this Response", jp.getCurrentLocation());
}

公共类ResponseDeserializer扩展JsonDeserializer{
@凌驾
公共响应反序列化（JsonParser jp，反序列化上下文ctxt）引发IOException{
ObjectMapper mapper=新的ObjectMapper（）；
响应数据=新响应（）；
对象数据=null；
对于（；jp.getCurrentToken（）！=JsonToken.END_对象；jp.nextToken（））{
字符串propName=jp.getCurrentName（）；
//跳过字段名：
jp.nextToken（）；
如果（“合同”。等于（名称））{
data=mapper.readValue（jp，Contract.class）；
}else if（“user”.equals（propName））{
data=mapper.readValue（jp，User.class）；
}else if（“status”.equals（propName））{
responseData.setStatus（jp.getText（））；
}else if（“error”.equals（propName））{
setError（mapper.readValue（jp，com.ingdirect.dg.business.object.community.api.common.Error.class））；
}
}
if（合同的数据实例）{
响应=新响应（响应数据）；
返回响应；
}
if（用户的数据实例）{
响应=新响应（响应数据）；
返回响应；
}
//在所有其他情况下，该类型尚未管理，请在需要时添加它
抛出新的JsonParseException（“无法解析此响应”，jp.getCurrentLocation（））；
}

}

有没有办法用注释来完成这项工作？提前谢谢

您是否尝试过：

public class AnyResponse {
    private String status;
    private Error error;
    private Contract contract;
    private User user;
    // And all other possibilities.
}
// ...
mapper.configure(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES, false);

这将填充JSON中出现的任何对象，并将其余对象保留为空

---

然后，您可以使用相关对象填写响应。

Jackson框架提供了对动态类型的内置支持

//Base type
@JsonTypeInfo(property = "type", use = Id.NAME)
@JsonSubTypes({ @Type(ValidResponse.class), 
                @Type(InvalidResponse.class) 
              })
public abstract class Response<T> {

} 
//Concrete type 1
public class ValidResponse extends Response<T>{

}
//Concrete type 2
public class InvalidResponse extends Response<T>{

}

main {
    ObjectMapper mapper = new ObjectMapper();
    //Now serialize
    ValidResponse response = (ValidResponse)(mapper.readValue(jsonString,      Response.class));

    //Deserialize
    String jsonString = mapper.writeValueAsString(response);
}

//基类型
@JsonTypeInfo（property=“type”，use=Id.NAME）
@JsonSubTypes（{@Type（ValidResponse.class）），
@类型（InvalidResponse.class）
})
公共抽象类响应{
} 
//混凝土类型1
公共类ValidResponse扩展了响应{
}
//混凝土类型2
公共类InvalidResponse扩展响应{
}
主要{
ObjectMapper mapper=新的ObjectMapper（）；
//现在连载
ValidResponse-response=（ValidResponse）（mapper.readValue（jsonString，response.class））；
//反序列化
字符串jsonString=mapper.writeValueAsString（响应）；
}

我就是这么做的。不过，谢谢你。

public class ResponseDeserializer extends JsonDeserializer<Response> {
@Override
public Response deserialize(JsonParser jp, DeserializationContext ctxt) throws IOException {
    ObjectMapper mapper = new ObjectMapper();
    Response responseData = new Response();
    Object data = null;

    for (; jp.getCurrentToken() != JsonToken.END_OBJECT; jp.nextToken()) {
        String propName = jp.getCurrentName();
        // Skip field name:
        jp.nextToken();

        if ("contract".equals(propName)) {
            data = mapper.readValue(jp, Contract.class);
        } else if ("user".equals(propName)) {
            data = mapper.readValue(jp, User.class);
        } else if ("status".equals(propName)) {
            responseData.setStatus(jp.getText());
        } else if ("error".equals(propName)) {
            responseData.setError(mapper.readValue(jp, com.ingdirect.dg.business.object.community.api.common.Error.class));
        }
    }

    if (data instanceof Contract) {
        Response<Contract> response = new Response<Ranking>(responseData);
        return response;
    }

    if (data instanceof User) {
        Response<User> response = new Response<User>(responseData);
        return response;
    }

    // in all other cases, the type is not yet managed, add it when needed
    throw new JsonParseException("Cannot parse this Response", jp.getCurrentLocation());
}

public class AnyResponse {
    private String status;
    private Error error;
    private Contract contract;
    private User user;
    // And all other possibilities.
}
// ...
mapper.configure(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES, false);

//Base type
@JsonTypeInfo(property = "type", use = Id.NAME)
@JsonSubTypes({ @Type(ValidResponse.class), 
                @Type(InvalidResponse.class) 
              })
public abstract class Response<T> {

} 
//Concrete type 1
public class ValidResponse extends Response<T>{

}
//Concrete type 2
public class InvalidResponse extends Response<T>{

}

main {
    ObjectMapper mapper = new ObjectMapper();
    //Now serialize
    ValidResponse response = (ValidResponse)(mapper.readValue(jsonString,      Response.class));

    //Deserialize
    String jsonString = mapper.writeValueAsString(response);
}