HBase REST过滤器（SingleColumnValueFilter） [英] HBase REST Filter ( SingleColumnValueFilter )

问题描述

我无法弄清楚如何在HBase REST界面中使用过滤器（HBase 0.90.4-cdh3u3）。文档只是给了我一个字符串的模式定义，但没有说明如何使用它。

I cannot figure out how to use filters in the HBase REST interface (HBase 0.90.4-cdh3u3). The documentation just gives me a schema definition for a "string", but doesn't show how to use it.

所以，我可以这样做：

curl -v -H 'Content-Type: text/xml' -d '<Scanner startRow="ddo" stopRow="ddp" batch="1024"/>' 'http://hbasegw:8080/table/scanner'

，然后用

and then retrieve with

curl -s -H "Content-Type: text/xml" http://hbasegw:8080/table/scanner/13293426893883128482b | tidy -i -q -xml

但是现在我想使用SingleColumnValueFilter并且必须以某种方式进行编码在XML中。
有没有人有这样的例子？

But now I want to use a SingleColumnValueFilter and have to encode that somehow in the XML. Does anyone have an example for this?

感谢，
马里奥

Thanks, Mario

推荐答案

扫描器XML中的过滤器字段是格式化为JSON的字符串。由于过滤器的JSON中包含许多引号，因此建议使用单独的文件来卷曲-d参数，以避免单引号。

Filter fields in the Scanner XML are strings formatted as JSON. Since the JSON for the filter has many quotes in it, I recommend using a separate file for curl's -d parameter, to avoid the single quote.

curl -v -HContent-Type：text / xml-d @ args.txt http ：// hbasegw：8080 / table / scanner

文件 args.txt 是：

Where the file args.txt is:

<Scanner startRow="cm93MDE=" endRow="cm93MDg=" batch="1024">
    <filter>
    {
        "latestVersion":true, "ifMissing":true, 
        "qualifier":"Y29sMQ==", "family":"ZmFtaWx5", 
        "op":"EQUAL", "type":"SingleColumnValueFilter", 
        "comparator":{"value":"MQ==","type":"BinaryComparator"}
    }
    </filter>
</Scanner>

您如何发现JSON过滤器字符串的外观？一种简单的方法，通过Java代码，从HBase的Java API给出一个标准的Filter对象，将字符串化的过滤器分离出来。

How do you discover how the JSON filter string should look like? Here's an easy way through Java code that spits out the stringified filter given a standard Filter object from HBase's Java API.

SingleColumnValueFilter filter = new SingleColumnValueFilter(
    Bytes.toBytes("family"),
    Bytes.toBytes("col1"),
    CompareFilter.CompareOp.EQUAL,
    Bytes.toBytes("1")
);
System.out.println(ScannerModel.stringifyFilter(filter));

请注意，JSON和XML需要使用Base64编码的数据。我已经在桌上测试了上面的curl命令，它工作得很好。

Notice that the JSON and the XML require data encoded in Base64. I've tested the above curl command on a table and it worked just fine.

如果您想知道，是的，扫描仪的REST API尚不像开发人员友好，因为它可以得到。

In case you are wondering, yes, the REST API for scanners is not yet as developer-friendly as it can get.

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