静态数据获取器返回 null (GraphQL/Java)答案

【问题标题】：Static data fetcher returns null (GraphQL/Java)静态数据获取器返回 null (GraphQL/Java)
【发布时间】：2019-06-21 22:24:48
【问题描述】：

我有以下简单的模式/查询示例，其中包含 Java 中的编程模式创建。在这里，我正在尝试创建以下架构：

query{
  board {
   name: string
 }
}

代码：

GraphQLObjectType queryType = GraphQLObjectType.newObject()
                .name("BoardQuery")
                .field(GraphQLFieldDefinition.newFieldDefinition()
                        .name("board")
                        .type(GraphQLObjectType.newObject().name("boardType")
                        .field(GraphQLFieldDefinition.newFieldDefinition()
                                .name("name")
                                .type(GraphQLString).build()))

                        .build())

                .build();

        GraphQLCodeRegistry graphQLCodeRegistry = GraphQLCodeRegistry.newCodeRegistry()
                .dataFetcher(FieldCoordinates.coordinates("boardType","name"),
                        new StaticDataFetcher("hello")).build();
        GraphQLSchema graphQLSchema = GraphQLSchema.newSchema()
                .query(queryType)
                .codeRegistry(graphQLCodeRegistry)
                .build();
        GraphQL graphQl = GraphQL.newGraphQL(graphQLSchema).build();
        ExecutionResult executionResult = graphQl.execute("query { board { name } }");
        System.out.println(executionResult.getData().toString());

预期输出：

{name:hello}

实际输出：

{name:null}

我错过了什么吗？

【问题讨论】：

标签： java graphql-java

【解决方案1】：

我自己是新手，但我会试一试。

    //The dataFetcher used to fetch a board object.
    DataFetcher boardDataFetcher() {
        return environment -> {
            Object board = new Object() {
                String name = "board Name";
            };
            return board;
        };
    }
    //Your deffinition of what a board type contains/what of the board type you want to expose
    public GraphQLObjectType boardType = newObject()
            .name("boardType")
            .field(newFieldDefinition()
                    .name("name")
                    .type(GraphQLString)
            )
            .build();
    // Define your query types 
    public GraphQLObjectType queryType = newObject()
            .name("Query")
            .field(newFieldDefinition()
                    .name("board")
                    .type(boardType)
            )
            .build();

    // wire the query, board and datafetcher together
    public GraphQLCodeRegistry codeRegistry = newCodeRegistry()
            .dataFetcher(
                    coordinates("Query", "board"), boardDataFetcher()
            )
            .build();
    //create the schema
    GraphQLSchema graphQLSchema = GraphQLSchema.newSchema()
            .query(queryType)
            .codeRegistry(codeRegistry)
            .build();

这适用于像

这样的查询

board{name}

应该给你答复：

"board": {
      "name": "board Name"
    }

【讨论】：