如何从HBase表中获取包含（或等于）特定ID的所有行？ [英] How to get all rows containing (or equaling) a particular ID from an HBase table?

问题描述

  HTable table = new HTable（Bytes）
我有一个方法可以选择rowkey包含传入参数的行。 .toBytes（objectsTableName），连接）; 
 
 public List< ObjectId> lookUp（String partialId）{
 if（partialId.matches（[a-fA-F0-9] +））{
 //从partialId创建一个正则表达式，它可以是
 //将任何包含partialId的rowkey作为子字符串，
 //然后获得具有指定rowkey的所有行
} else {
 throw new IllegalArgumentException（
query must只能用十六进制值完成）; 
} 
} 
  

我不知道如何完成上面的代码。

我只知道以下代码可以在Hbase中获得具有指定rowkey的行。

 字符串rowkey =123; 
 Get get = new Get（Bytes.toBytes（rowkey））; 
结果结果= table.get（get）; 
  

解决方案

您可以使用 RowFilter 使用 RegexStringComparator 来做到这一点。或者，如果只是获取匹配给定子字符串的行，您可以将RowFilter与 SubstringComparator 。这是你如何使用HBase过滤器：

  public static void main（String [] args）throws IOException {
 
 Configuration conf = HBaseConfiguration.create（）; 
 HTable表=新的HTable（conf，demo）; 
扫描s =新扫描（）; 
 Filter f = new RowFilter（CompareOp.EQUAL，new SubstringComparator（abc））; 
 s.setFilter（f）; 
 ResultScanner rs = table.getScanner（s）; 
 for（Result r：rs）{
 System.out.println（RowKey：+ Bytes.toString（r.getRow（）））; 
 //其余的逻辑
} 
 rs.close（）; 
 table.close（）; 
} 
  

上面这段代码会给你所有包含 abc 作为其行键的一部分。

HTH

I have a method which select the row whose rowkey contains the parameter passed into.

HTable table = new HTable(Bytes.toBytes(objectsTableName), connection);

public List<ObjectId> lookUp(String partialId) {
    if (partialId.matches("[a-fA-F0-9]+")) {
        // create a regular expression from partialId, which can 
        //match any rowkey that contains partialId as a substring, 
        //and then get all the row with the specified rowkey 
    } else {
        throw new IllegalArgumentException(
                "query must be done with hexadecimal values only");
    }
}

I don't know how to finish code above.

I just know the following code can get the row with specified rowkey in Hbase.

String rowkey = "123";
Get get = new Get(Bytes.toBytes(rowkey));
Result result = table.get(get);

解决方案

You can use RowFilter filter with RegexStringComparator to do that. Or, if it is just to fetch the rows which match a given substring you can use RowFilter with SubstringComparator. This is how you use HBase filters :

public static void main(String[] args) throws IOException {

        Configuration conf = HBaseConfiguration.create();
        HTable table = new HTable(conf, "demo");
        Scan s = new Scan();
        Filter f = new RowFilter(CompareOp.EQUAL, new SubstringComparator("abc"));
        s.setFilter(f);
        ResultScanner rs = table.getScanner(s);
        for(Result r : rs){
            System.out.println("RowKey : " + Bytes.toString(r.getRow()));
            //rest of your logic            
        }
        rs.close();
        table.close();
}

The above piece of code will give you all the rows which contain abc as a part of their rowkeys.

HTH

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