如何使用graphql-java上传文件? [英] How to upload files with graphql-java?

问题描述

如果我使用graphql-java，我不知道如何上传文件，有人可以给我演示吗?我将不胜感激！

I can't find out how to upload files if i use graphql-java, can someone show me a demo? I will be appreciated!

参考: https://github.com/graphql -java-kickstart/graphql-java-tools/issues/240

我在springboot中通过使用graphql-java-kickstart graphql-java-tools进行了尝试，但是没有用

I tried it in springboot by using graphql-java-kickstart graphql-java-tools, but it didn't work

@Component
public class FilesUpload implements GraphQLMutationResolver {

    public Boolean testMultiFilesUpload(List<Part> parts, DataFetchingEnvironment env) {
        // get file parts from DataFetchingEnvironment, the parts parameter is not used
        List<Part> attchmentParts = env.getArgument("files");
        System.out.println(attchmentParts);
        return true;
    }
}

这是我的模式

type Mutation {
    testSingleFileUpload(file: Upload): UploadResult
}

我希望这个解析器可以打印attchmentParts，所以我可以获取文件的一部分.

I expect this resolver can print attchmentParts,so i can get the file part.

推荐答案

1. 在我们的架构中定义标量类型

1. define a scalar type in our schema

scalar Upload

我们应该为上载配置GraphQLScalarType，请在下面使用它:

and we should configure GraphQLScalarType for Upload, use this below:

@Configuration
public class GraphqlConfig {

   @Bean
   public GraphQLScalarType uploadScalarDefine() {
      return ApolloScalars.Upload;
   } 
}

然后我们将在方案中定义一个突变，并为testMultiFilesUpload定义一个GraphQLMutationResolver

then we would define a mutation in schema and a GraphQLMutationResolver for testMultiFilesUpload

type Mutation {
  testMultiFilesUpload(files: [Upload!]!): Boolean
}

这是解析器:

public Boolean testMultiFilesUpload(List<Part> parts, DataFetchingEnvironment env) {
    // get file parts from DataFetchingEnvironment, the parts parameter is not use
    List<Part> attachmentParts = env.getArgument("files");
    int i = 1;
    for (Part part : attachmentParts) {
      String uploadName = "copy" + i;
      try {
        part.write("your path:" + uploadName);
      } catch (IOException e) {
        e.printStackTrace();
      }
      i++;
    }
    return true;   
  }
}

1. 为javax.servlet.http.Part配置jackson解串器并将其注册到ObjectMapper

1. configure a jackson deserializer for javax.servlet.http.Part and register it to ObjectMapper

public class PartDeserializer extends JsonDeserializer<Part> {

  @Override
  public Part deserialize(JsonParser p, DeserializationContext ctxt) throws IOException, JsonProcessingException {         
     return null;
  }
}

为什么我们返回null?因为List<Part> parts始终为null，所以在解析程序的方法中，从DataFetchingEnvironment中获取parts参数；

why we return null? because the List<Part> parts always null ,In the resolver's method, get the parts argument from the DataFetchingEnvironment;

environment.getArgument(文件")

environment.getArgument("files")

将其注册到ObjectMapper:

register it to ObjectMapper:

@Bean
public ObjectMapper objectMapper() {
  ObjectMapper objectMapper = new ObjectMapper();
  objectMapper.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false);
  SimpleModule module = new SimpleModule();
  module.addDeserializer(Part.class, new PartDeserializer());
  objectMapper.registerModule(module);
  return objectMapper;
}

1. 要对此进行测试，请将以下表单数据(我们使用Postman)发布到GraphQL端点

operations

{ "query": "mutation($files: [Upload!]!) {testMultiFilesUpload(files:$files)}", "variables": {"files": [null,null] } }

map

{ "file0": ["variables.files.0"] , "file1":["variables.files.1"]}

file0

your file

file1

your file

像这样:

请记住选择表单数据选项

remember to select the form-data option

通过此操作，我们可以上传多个文件

这篇关于如何使用graphql-java上传文件?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！