获取HBase中的筛选行

在应用一些过滤器后，我正在尝试从HBase中获取行中的选定列。考虑一个表格：

ename:fname ename:lname工资总额：da工资：ta

我想获得总工资>1500的所有员工的列表。为此，我编写了以下代码。我面临的问题是，当我筛选列时，我只会在输出中得到该筛选器，这是有意义的，因为这是创建这些列的目的，但如果我希望得到所需的列，但只希望根据特定列进行筛选，如我刚才提到的—所有薪资>1500的员工列表

输出应为以下一组列：

lname，fname，薪水：总额，薪水：ta

迄今为止的代码 解决方案1

---

ValueFilter 此筛选器允许仅包含具有特定值的列

这就是为什么您只能获得在筛选器中指定的列

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如果我错了，请告诉我，但您要做的是在薪资>1500时检索所有列，不是吗？

您的要求是相关的。因此，我建议您在HBase上使用包装器，以使生活更轻松

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考虑使用：。它是一个针对HBase的高性能SQL包装器，使用它可以运行如下查询：

select*from emp where salary>1500

您应该使用and（或addColumn）的组合

见下表（目前我无法在我的终端进行测试）：

---

您的工资真的保存为表示字符串的字节吗？这可能是个问题，因为字符串

“900”

大于字符串

“1500”

。我建议将参数

CompareOp.greater

替换为

CompareOperator.greater

，因为第一个参数已被弃用。

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.KeyValue;
import org.apache.hadoop.hbase.client.Get;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.ResultScanner;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.filter.BinaryComparator;
import org.apache.hadoop.hbase.filter.RegexStringComparator;
import org.apache.hadoop.hbase.filter.SubstringComparator;
import org.apache.hadoop.hbase.filter.CompareFilter;
import org.apache.hadoop.hbase.filter.Filter;
import org.apache.hadoop.hbase.filter.QualifierFilter;
import org.apache.hadoop.hbase.filter.FamilyFilter;
import org.apache.hadoop.hbase.filter.FilterList;
import org.apache.hadoop.hbase.filter.ValueFilter;
import org.apache.hadoop.hbase.util.Bytes;


import java.io.IOException;
import java.util.ArrayList;
import java.util.List;


public class MyQualifierFilterExample {

  public static void main(String[] args) throws IOException {
    Configuration conf = HBaseConfiguration.create();

    HTable table = new HTable(conf, "emp");

    List<Filter> filters = new ArrayList<Filter>();

    Filter famFilter = new FamilyFilter(CompareFilter.CompareOp.EQUAL,
              new BinaryComparator(Bytes.toBytes("salary")));
    filters.add(famFilter);

    Filter colFilter = new QualifierFilter(CompareFilter.CompareOp.EQUAL,
      new BinaryComparator(Bytes.toBytes("gross")));

    filters.add(colFilter);

    Filter valFilter = new ValueFilter(CompareFilter.CompareOp.GREATER_OR_EQUAL,
              new BinaryComparator(Bytes.toBytes("1500")));

    filters.add(valFilter);

    FilterList fl = new FilterList( FilterList.Operator.MUST_PASS_ALL, filters);


    Scan scan = new Scan();
    scan.setFilter(fl);
    ResultScanner scanner = table.getScanner(scan);
    System.out.println("Scanning table... ");
    for (Result result : scanner) {
        //System.out.println("getRow:"+Bytes.toString(result.getRow()));
        for (KeyValue kv : result.raw()) {
            //System.out.println("Family - "+Bytes.toString(kv.getFamily()));
            //System.out.println("Qualifier - "+Bytes.toString(kv.getQualifier() ));
            System.out.println("kv:"+kv +", Key: " + Bytes.toString(kv.getRow())  + ", Value: " +Bytes.toString(kv.getValue()));
        }
    }   

    scanner.close();
    System.out.println("Completed ");
  }
}

Scanning table... 
kv:101/salary:gross/1339876269770/Put/vlen=4, Key: 101, Value: 2000
kv:102/salary:gross/1339876277659/Put/vlen=4, Key: 102, Value: 2400
kv:105/salary:gross/1339876300585/Put/vlen=4, Key: 105, Value: 2300
kv:106/salary:gross/1339876310004/Put/vlen=4, Key: 106, Value: 2900
Completed 

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.KeyValue;
import org.apache.hadoop.hbase.client.Get;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.ResultScanner;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.filter.BinaryComparator;
import org.apache.hadoop.hbase.filter.RegexStringComparator;
import org.apache.hadoop.hbase.filter.SubstringComparator;
import org.apache.hadoop.hbase.filter.CompareFilter;
import org.apache.hadoop.hbase.filter.Filter;
import org.apache.hadoop.hbase.filter.QualifierFilter;
import org.apache.hadoop.hbase.filter.SingleColumnValueFilter;
import org.apache.hadoop.hbase.filter.FamilyFilter;
import org.apache.hadoop.hbase.filter.FilterList;
import org.apache.hadoop.hbase.filter.ValueFilter;
import org.apache.hadoop.hbase.util.Bytes;


import java.io.IOException;
import java.util.ArrayList;
import java.util.List;


public class MyQualifierFilterExample {

  public static void main(String[] args) throws IOException {
    Configuration conf = HBaseConfiguration.create();

    HTable table = new HTable(conf, "emp");

    List<Filter> filters = new ArrayList<Filter>();

    SingleColumnValueFilter colValFilter = new SingleColumnValueFilter(Bytes.toBytes("salary"), Bytes.toBytes("gross")
            , CompareFilter.CompareOp.GREATER_OR_EQUAL, new BinaryComparator(Bytes.toBytes("1300")));
    colValFilter.setFilterIfMissing(false);
    filters.add(colValFilter);          

    Filter colValFilter2 = new SingleColumnValueFilter(Bytes.toBytes("salary"), Bytes.toBytes("da")
            , CompareFilter.CompareOp.GREATER_OR_EQUAL, new BinaryComparator(Bytes.toBytes("150")));
    filters.add(colValFilter2);

    //Filter colValFilter3 = new SingleColumnValueFilter(Bytes.toBytes("ename"), Bytes.toBytes("fname")
    //      , CompareFilter.CompareOp.GREATER_OR_EQUAL, new SubstringComparator("jack"));
    //filters.add(colValFilter3);

    FilterList fl = new FilterList( FilterList.Operator.MUST_PASS_ALL, filters);


    Scan scan = new Scan();
    scan.setFilter(fl);
    scan.addColumn(Bytes.toBytes("ename"), Bytes.toBytes("fname"));
    scan.addColumn(Bytes.toBytes("ename"), Bytes.toBytes("lname"));
    scan.addColumn(Bytes.toBytes("salary"), Bytes.toBytes("gross"));
    scan.addColumn(Bytes.toBytes("salary"), Bytes.toBytes("da"));

    ResultScanner scanner = table.getScanner(scan);
    String key = new String("~");
    String keyFlag = new String("~");
    System.out.println("Scanning table... ");
    for (Result result : scanner) {
        //System.out.println("getRow:"+Bytes.toString(result.getRow()));
        key = "~";
        for (KeyValue kv : result.raw()) {

            if (key.compareTo(keyFlag)==0)
            {
                key = Bytes.toString(kv.getRow());
                System.out.print("Key: " + key);
            }
            //System.out.print("Family - "+Bytes.toString(kv.getFamily()));

            //System.out.print(", Buffer - "+Bytes.toString(kv.getBuffer() ));
            //System.out.print(", FamilyOffset - " + kv.getFamilyOffset() );
            System.out.print(", "+Bytes.toString(kv.getFamily())+"."+Bytes.toString(kv.getQualifier()));
            System.out.print("=" +Bytes.toString(kv.getValue()));
        }
        System.out.println("");
        System.out.println("-------------------");
    }   

    scanner.close();
    System.out.println("Completed ");
  }
}

Scanning table... 
Key: 103, ename.fname=peter, ename.lname=parker, salary.da=190, salary.gross=1400
-------------------
Key: 105, ename.fname=harry, ename.lname=potter, salary.da=154, salary.gross=2300
-------------------
Completed 

SingleColumnValueFilter filter = new SingleColumnValueFilter(
    Bytes.toBytes("salary"),
    Bytes.toBytes("gross"),
    CompareOp.GREATER,
    Bytes.toBytes("1500")
);
//To prevent the entire row from being emitted
//if the column is not found on a row
scan.setFilterIfMissing(true)
scan.setFilter(filter);

scan.addFamily(Bytes.toBytes("ename"))
scan.addColumn(Bytes.toBytes("salary"), Bytes.toBytes("da"))
scan.addColumn(Bytes.toBytes("salary"), Bytes.toBytes("gross"))