Java中的Dgraph。如何运行原始字符串突变查询？

Question

我需要能够在不使用 newBuilder() 的情况下运行原始字符串突变查询：

Gson gson = new Gson();
String json = gson.toJson(newEmployer);
Transaction newTransaction = this.dgraphClient.newTransaction();
Mutation mu = Mutation.newBuilder().setSetJson(ByteString.copyFromUtf8(json.toString())).build();
newTransaction.mutate(mu);

我想跑步：

String email = "ba@a.aa";
String userType = "JOB_SEEKER";
Transaction newTransaction = this.dgraphClient.newTransaction();
String query = 
        "{\n" +
        "    set { \n" +
        "       _:user <label> \"USER\" . \n" +
        "      _:user <userType> \"" + email + "\" . \n" +
        "      _:user <email> \"" + userType + "\" . \n" +
        "    }\n" +
        "}";
Mutation mu = Mutation.parseFrom(ByteString.copyFromUtf8(query));
newTransaction.mutate(mu);

但我在运行时收到错误消息：“在解析协议消息时，输入意外在字段中间结束。这可能意味着输入已被截断或嵌入的消息误报了自己的长度。”

Answer 1

在 gRPC 客户端（例如 dgraph4j）中为突变设置 N-Quad Triples 时，您只需自己指定换行符分隔的三元组并将它们传递给Mutation#setSetNquads。他们没有被set包围。换句话说，而不是这样：

{
  set {
    _:user <label> "USER" .
    _:user <userType> "USER_TYPE" .
    _:user <email> "ba@a.aa" .
  }
}

你只需要三元组：

_:user <label> "USER" .
_:user <userType> "USER_TYPE" .
_:user <email> "ba@a.aa" .

下面是它在 Java 代码中的样子：

String email = "ba@a.aa";
String userType = "JOB_SEEKER";
Transaction newTransaction = this.dgraphClient.newTransaction();
String triples = 
        "_:user <label> \"USER\" .\n" +
        "_:user <userType> \"" + email + "\" .\n" +
        "_:user <email> \"" + userType + "\" .";
Mutation mu =
    Mutation.newBuilder()
        .setSetNquads(ByteString.copyFromUtf8(triples))
        .build();
Assigned assigned = newTransaction.mutate(mu);

{ set { ... } } 的第一个突变格式用于 HTTP 客户端，其中包括 Dgraph Ratel 或 curl 中的突变。

有关 Dgraph 突变的更多信息，请参阅突变文档：https://docs.dgraph.io/mutations/

Answer 2

我找到了一些解决方案，它不是字符串，但它有效。

JSONObject query = new JSONObject();
query.put("label", "USER");
query.put("userType", userType);
query.put("email", email);
Mutation mu = Mutation.newBuilder().setSetJson(ByteString.copyFromUtf8(query.toJSONString())).build();