转自:http://blog.chinaunix.net/uid-77311-id-4617954.html
RowFilter是用来对rowkey进行过滤的,比较符如下:
Operator
|
Description
|
LESS
|
小于
|
LESS_OR_EQUAL
|
小于等于
|
EQUAL
|
等于
|
NOT_EQUAL
|
不等于
|
GREATER_OR_EQUAL
|
大于等于
|
GREATER
|
大于
|
NO_OP
|
排除所有
|
Comparator
|
Description
|
BinaryComparator
|
使用
Bytes.compareTo()
比较
|
BinaryPrefixComparator
|
和
BinaryComparator
差不多,从前面开始比较
|
NullComparator
|
Does not compare against an actual value but whether a given one is null, or not null.
|
BitComparator
|
Performs a bitwise comparison, providing a BitwiseOp class with AND, OR, and XOR operators.
|
RegexStringComparator
|
正则表达式
|
SubstringComparator
|
把数据当成字符串,用
contains()
来判断
|
下面是相关比较符的例子
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- package com.hxl;
- import java.io.IOException;
- import org.apache.hadoop.conf.Configuration;
- import org.apache.hadoop.hbase.Cell;
- import org.apache.hadoop.hbase.CellUtil;
- import org.apache.hadoop.hbase.KeyValue;
- 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.CompareFilter;
- import org.apache.hadoop.hbase.filter.Filter;
- import org.apache.hadoop.hbase.filter.RowFilter;
- import org.apache.hadoop.hbase.util.Bytes;
- import com.hxl.ConnectDB;
- public class RowFilterTest {
- public void rowfilter(String tablename, String rowkeyvalue) {
- Configuration configuration = null;
- configuration = new ConnectDB().getConf(); //根据自己需要自行更换
- try {
- HTable table = new HTable(configuration, tablename);
- Filter filter1 = new RowFilter(CompareFilter.CompareOp.EQUAL,
- new BinaryComparator(Bytes.toBytes(rowkeyvalue)));
- // EQUAL =
- Scan s = new Scan();
- s.setFilter(filter1);
- ResultScanner rs = table.getScanner(s);
- for (Result r : rs) {
- System.out.println("rowkey:" + new String(r.getRow()));
- for (KeyValue keyValue : r.raw()) {
- System.out.println("列族:" + new String(keyValue.getFamily())
- + " 列:" + new String(keyValue.getQualifier()) + ":"
- + new String(keyValue.getValue()));
- }
- }
- } catch (IOException e) {
- // TODO Auto-generated catch block
- e.printStackTrace();
- }
- }
- }
相关的过滤方法使用:
提取rowkey以01结尾数据
Filter filter = new RowFilter(CompareFilter.CompareOp.EQUAL,new RegexStringComparator(".*01$"));
提取rowkey以包含201407的数据
Filter filter = new RowFilter(CompareFilter.CompareOp.EQUAL,new SubstringComparator("201407"));
提取rowkey以123开头的数据
Filter filter = new RowFilter(CompareFilter.CompareOp.EQUAL,new BinaryPrefixComparator("123".getBytes()));
-- The End --