environment.getArgument 无法在 graphql-java 中转换为我自己的 java 对象
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【中文标题】environment.getArgument 无法在 graphql-java 中转换为我自己的 java 对象【英文标题】:environment.getArgument can't cast to my own java object in graphql-java 【发布时间】:2017-12-22 14:32:59 【问题描述】:由于以下错误 ExecutionStrategy.resolveField() - 获取数据时出现异常 java.lang.ClassCastException: java.util.LinkedHashMap 与 com.fathome.graphql.OffersDto 不兼容,我无法将输入对象转换为 DTO
OffersDto inputObject = environment.getArgument("offersInput");
请让我知道下面的代码有什么问题,在此先感谢。
package com.fathome.graphql;
import graphql.schema.*;
import static graphql.Scalars.*;
import static graphql.schema.GraphQLFieldDefinition.newFieldDefinition;
import static graphql.schema.GraphQLInputObjectField.newInputObjectField;
import static graphql.schema.GraphQLInputObjectType.newInputObject;
import static graphql.schema.GraphQLList.list;
import static graphql.schema.GraphQLObjectType.newObject;
public class ManualGraphQLQuerySchema
public static GraphQLObjectType offersResponse = newObject()
.name("OffersResponse")
.field(newFieldDefinition()
.name("offerName")
.type(GraphQLString))
.field(newFieldDefinition()
.name("offerId")
.type(GraphQLString))
.build();
public static GraphQLInputObjectType offersRequestType = GraphQLInputObjectType.newInputObject()
.name("OffersDto")
.field(newInputObjectField()
.name("offerName")
.type(GraphQLString))
.field(newInputObjectField()
.name("offerId")
.type(GraphQLString))
.build();
public static GraphQLObjectType queryType = newObject()
.name("QueryType")
.field(newFieldDefinition()
.name("offers")
.type(offersResponse)
.argument(GraphQLArgument.newArgument()
.name("offersInput")
.type(offersRequestType))
.dataFetcher(new OffersFetcher()))
.build();
package com.fathome.graphql;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonPropertyOrder;
@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonPropertyOrder(
"offerName",
"offerId"
)
public class OffersDto
@JsonProperty("offerName")
private String offerName;
@JsonProperty("offerName")
public String getOfferName()
return offerName;
@JsonProperty("offerName")
public void setOfferName(String offerName)
this.offerName = offerName;
@JsonProperty("offerId")
private String offerId;
@JsonProperty("offerId")
public String getOfferId()
return offerId;
@JsonProperty("offerId")
public void setOfferId(String offerId)
this.offerId = offerId;
package com.fathome.graphql;
import graphql.schema.DataFetcher;
import graphql.schema.DataFetchingEnvironment;
public class OffersFetcher implements DataFetcher<OffersDto>
@Override
public OffersDto get(DataFetchingEnvironment environment)
//Can't cast input object DTO this is error in below line
//ExecutionStrategy.resolveField() - Exception while fetching data
//java.lang.ClassCastException: java.util.LinkedHashMap incompatible with com.fathome.graphql.OffersDto
OffersDto inputObject = environment.getArgument("offersInput");
//calling service to get offerdetails using inputObject
//for testing not calling service just returning mock object.
OffersDto offersDto = new OffersDto();
offersDto.setOfferName("123");
offersDto.setOfferId("456");
return offersDto;
在下面的参考链接中类似于我的代码工作正常。
剧集情节 = environment.getArgument("episode"); ReviewInput review = environment.getArgument("review");
http://graphql-java.readthedocs.io/en/latest/execution.html
【问题讨论】:
【参考方案1】:如果是对象 GraphQL 输入类型(如您的情况),您从 environment.getArgument(...)
获得的值将是标量值(字符串、数字等)或 Map
。
然后,您需要自己进行反序列化。由于您使用的是 Jackson,它看起来像这样:
private final ObjectMapper objectMapper;
...
Object rawInput = environment.getArgument("offersInput");
OffersDto inputObject = objectMapper.convertValue(rawInput, OffersDto.class);
查看graphql-java-tools 了解架构优先方法,或查看graphql-spqr 了解代码优先方法,两者都使DataFetcher
s 完全透明,因此不需要像上面那样的手动步骤。
【讨论】:
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