使用H2OApi Java绑定来检索H2O帧 [英] Using H2OApi Java bindings to retrieve H2O Frame
问题描述
我使用H2O Java绑定提供的H2O（3.10.4.7）REST Api处理Java项目，我遇到以下问题：
I work on a Java project using the H2O (3.10.4.7) REST Api provided by the H2O Java bindings and I have the following problem:
我们需要从现有H2O框架中检索元数据，例如：
We need to retrieve Metadata from existing H2O Frames like:
- 列名称和
- 这些列的数据类型，
最好使用H2oApi.class。
preferrably using the H2oApi.class.
我们的方法是获取一个从H2O框架行，然后使用它来获取我们需要的元数据。
Our approach is to fetch one Row from the H2O Frame and then use it to get the Metadata we need.
到目前为止，我尝试了以下内容：
So far I tried the following:
FramesV3 targetFrame = new FramesV3();
targetFrame.frameId = frameKey; // key provided by import process - works
targetFrame.rowCount = 1; // get one row to figure out specs of all cols
H2OApi h2oApi = new H2OApi("http://localhost:54321/");
FramesV3 result = h2oApi.frames(targetFrame);
我得到这个例外：
java.lang.IllegalArgumentException: @Field parameters can only be used with form encoding. (parameter #1)
for method Frames.list
at retrofit2.ServiceMethod$Builder.methodError(ServiceMethod.java:695)
at retrofit2.ServiceMethod$Builder.methodError(ServiceMethod.java:686)
at retrofit2.ServiceMethod$Builder.parameterError(ServiceMethod.java:704)
at retrofit2.ServiceMethod$Builder.parseParameterAnnotation(ServiceMethod.java:476)
at retrofit2.ServiceMethod$Builder.parseParameter(ServiceMethod.java:328)
at retrofit2.ServiceMethod$Builder.build(ServiceMethod.java:201)
at retrofit2.Retrofit.loadServiceMethod(Retrofit.java:166)
at retrofit2.Retrofit$1.invoke(Retrofit.java:145)
at com.sun.proxy.$Proxy14.list(Unknown Source)
at water.bindings.H2oApi.frames(H2oApi.java:882)
at H2ORestCloudTests.getSpecFromFrameTest(H2ORestCloudTests.java:388)
如果我使用REST API框架端点通过浏览器它的工作原理。
示例：
If I use the REST API Frames Endpoint via Browser it works. Example:
"http://localhost:54321/3/Frames/89a05762-4bcd-41d8-a800-f9cfc3ac73dd?row_count=1"
浏览器中的结果：
{
"__meta": {
"schema_version": 3,
"schema_name": "FramesV3",
"schema_type": "Frames"
},
"_exclude_fields": "",
"row_offset": 0,
"row_count": 1,
"column_offset": 0,
"column_count": 0,
"job": null,
"frames": [
{
"__meta": {
"schema_version": 3,
"schema_name": "FrameV3",
"schema_type": "Frame"
},
"_exclude_fields": "",
"frame_id": {
"__meta": {
"schema_version": 3,
"schema_name": "FrameKeyV3",
"schema_type": "Key<Frame>"
},
"name": "89a05762-4bcd-41d8-a800-f9cfc3ac73dd",
"type": "Key<Frame>",
"URL": "/3/Frames/89a05762-4bcd-41d8-a800-f9cfc3ac73dd"
},
"byte_size": 1928,
"is_text": false,
"row_offset": 0,
"row_count": 1,
"column_offset": 0,
"column_count": 5,
"total_column_count": 5,
"checksum": -7731554748204616990,
"rows": 150,
"num_columns": 5,
"default_percentiles": [
0.001,
0.01,
0.1,
0.2,
0.25,
0.3,
0.3333333333333333,
0.4,
0.5,
0.6,
0.6666666666666666,
0.7,
0.75,
0.8,
0.9,
0.99,
0.999
],
"columns": [
{
"__meta": {
"schema_version": 3,
"schema_name": "ColV3",
"schema_type": "Vec"
},
"label": "sepal_length",
"missing_count": 0,
"zero_count": 0,
"positive_infinity_count": 0,
"negative_infinity_count": 0,
"mins": [
4.3,
4.4,
4.4,
4.4,
4.5
],
"maxs": [
7.9,
7.7,
7.7,
7.7,
7.7
],
"mean": 5.843333333333334,
"sigma": 0.8280661279778637,
"type": "real",
"domain": null,
"domain_cardinality": 0,
"data": [
5.1000000000000005
],
"string_data": null,
"precision": 1,
"histogram_bins": null,
"histogram_base": 0.0,
"histogram_stride": 0.0,
"percentiles": null
},
...
}
我是否遗漏了某些内容，或者是否有更好的方法可以通过H2O Java Rest API获取这些Frame信息？
Am I missing something or is there maybe a better way to get those Frame infos via the H2O Java Rest API?
提前感谢您，祝您愉快！
Thank you in advance and have a nice day!
Nico
推荐答案
回答原始问题（例外）这确实是H2O中的一个错误，目前除了从此分支。
To answer the original question (exception) this is indeed a bug in H2O, currently there's no workaround besides building from this branch.
如指出的那样out此方法不返回元数据，将在中回答此部分这个问题。
As pointed out this method does not return the metadata, will answer this part in this question.
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