前言：本文详细介绍了 HBase QualifierFilter 过滤器 Java&Shell API 的使用，并贴出了相关示例代码以供参考。QualifierFilter 基于列名进行过滤，在工作中涉及到需要通过HBase 列名进行数据过滤时可以考虑使用它。比较器细节及原理请参照之前的更文：HBase Filter 过滤器之比较器 Comparator 原理及源码学习
一。Java Api
头部代码
/**
* 用于列名（Qualifier）过滤。
*/
public class QualifierFilterDemo {
private static boolean isok = false;
private static String tableName = "test";
private static String[] cfs = new String[]{"f"};
private static String[] data = new String[]{
"row-1:f:name:Wang", "row-1:f:age:20",
"row-2:f:name:Zhou", "row-2:f:age:10",
"row-3:f:gender:男", "row-3:f:name:Li",
"row-4:f:namana:xyz", "row-4:f:age:Zhao"
};
public static void main(String[] args) throws IOException {
MyBase myBase = new MyBase();
Connection connection = myBase.createConnection();
if (isok) {
myBase.deleteTable(connection, tableName);
myBase.createTable(connection, tableName, cfs);
// 造数据
myBase.putRows(connection, tableName, data);
}
Table table = connection.getTable(TableName.valueOf(tableName));
Scan scan = new Scan();
中部代码
向右滑动滚动条可查看输出结果。
1. BinaryComparator 构造过滤器
QualifierFilter qualifierFilter = new QualifierFilter(CompareFilter.CompareOp.EQUAL, new BinaryComparator(Bytes.toBytes("age"))); // [row-1:f:age, row-2:f:age, row-4:f:age]
QualifierFilter qualifierFilter = new QualifierFilter(CompareFilter.CompareOp.NOT_EQUAL, new BinaryComparator(Bytes.toBytes("name"))); // [row-1:f:age, row-2:f:age, row-3:f:gender, row-4:f:age, row-4:f:namana]
QualifierFilter qualifierFilter = new QualifierFilter(CompareFilter.CompareOp.GREATER, new BinaryComparator(Bytes.toBytes("gender"))); // [row-1:f:name, row-2:f:name, row-3:f:name, row-4:f:namana]
QualifierFilter qualifierFilter = new QualifierFilter(CompareFilter.CompareOp.GREATER_OR_EQUAL, new BinaryComparator(Bytes.toBytes("name"))); // [row-1:f:name, row-2:f:name, row-3:f:name]
QualifierFilter qualifierFilter = new QualifierFilter(CompareFilter.CompareOp.LESS, new BinaryComparator(Bytes.toBytes("gender"))); // [row-1:f:age, row-2:f:age, row-4:f:age]
QualifierFilter qualifierFilter = new QualifierFilter(CompareFilter.CompareOp.LESS_OR_EQUAL, new BinaryComparator(Bytes.toBytes("gender"))); // [row-1:f:age, row-2:f:age, row-3:f:gender, row-4:f:age]
2. BinaryPrefixComparator 构造过滤器
QualifierFilter qualifierFilter = new QualifierFilter(CompareFilter.CompareOp.EQUAL, new BinaryPrefixComparator(Bytes.toBytes("nam"))); // [row-1:f:name, row-2:f:name, row-3:f:name, row-4:f:namana]
QualifierFilter qualifierFilter = new QualifierFilter(CompareFilter.CompareOp.NOT_EQUAL, new BinaryPrefixComparator(Bytes.toBytes("nam"))); // [row-1:f:age, row-2:f:age, row-3:f:gender, row-4:f:age]
QualifierFilter qualifierFilter = new QualifierFilter(CompareFilter.CompareOp.GREATER, new BinaryPrefixComparator(Bytes.toBytes("g"))); // [row-1:f:name, row-2:f:name, row-3:f:name, row-4:f:namana]
QualifierFilter qualifierFilter = new QualifierFilter(CompareFilter.CompareOp.GREATER_OR_EQUAL, new BinaryPrefixComparator(Bytes.toBytes("n"))); // [row-1:f:name, row-2:f:name, row-3:f:name, row-4:f:namana]
QualifierFilter qualifierFilter = new QualifierFilter(CompareFilter.CompareOp.LESS, new BinaryPrefixComparator(Bytes.toBytes("m"))); // [row-1:f:age, row-2:f:age, row-3:f:gender, row-4:f:age]
QualifierFilter qualifierFilter = new QualifierFilter(CompareFilter.CompareOp.LESS_OR_EQUAL, new BinaryPrefixComparator(Bytes.toBytes("a"))); // [row-1:f:age, row-2:f:age, row-4:f:age]
3. SubstringComparator 构造过滤器
QualifierFilter qualifierFilter = new QualifierFilter(CompareFilter.CompareOp.EQUAL, new SubstringComparator("g")); // [row-1:f:age, row-2:f:age, row-3:f:gender, row-4:f:age]
QualifierFilter qualifierFilter = new QualifierFilter(CompareFilter.CompareOp.NOT_EQUAL, new SubstringComparator("n")); // [row-1:f:age, row-2:f:age, row-4:f:age]
4. RegexStringComparator 构造过滤器
QualifierFilter qualifierFilter = new QualifierFilter(CompareFilter.CompareOp.NOT_EQUAL, new RegexStringComparator("nam")); // [row-1:f:age, row-2:f:age, row-3:f:gender, row-4:f:age]
QualifierFilter qualifierFilter = new QualifierFilter(CompareFilter.CompareOp.EQUAL, new RegexStringComparator("nam")); // [row-1:f:name, row-2:f:name, row-3:f:name, row-4:f:namana]
QualifierFilter qualifierFilter = new QualifierFilter(CompareFilter.CompareOp.EQUAL, new RegexStringComparator("n[a-z]m")); // [row-1:f:name, row-2:f:name, row-3:f:name, row-4:f:namana]
尾部代码
scan.setFilter(qualifierFilter);
ResultScanner scanner = table.getScanner(scan);
Iterator iterator = scanner.iterator();
LinkedList rowkeys = new LinkedList<>();
while (iterator.hasNext()) {
Result result = iterator.next();
String rowkey = Bytes.toString(result.getRow());
rowkeys.add(rowkey);
}
System.out.println(rowkeys);
scanner.close();
table.close();
connection.close();
}
}
二。Shell Api
1. BinaryComparator 构造过滤器
方式一：
hbase(main):003:0> scan 'test',{FILTER=>"QualifierFilter(=,'binary:age')"}
ROW COLUMN+CELL
row-1 column=f:age, timestamp=1589252853542, value=20
row-2 column=f:age, timestamp=1589252853542, value=10
row-4 column=f:age, timestamp=1589252853542, value=Zhao
3 row(s) in 0.0680 seconds
支持的比较运算符：= != > >= < <=，不再一一举例。
方式二：
import org.apache.hadoop.hbase.filter.CompareFilter
import org.apache.hadoop.hbase.filter.BinaryComparator
import org.apache.hadoop.hbase.filter.QualifierFilter
hbase(main):010:0> scan 'test',{FILTER => QualifierFilter.new(CompareFilter::CompareOp.valueOf('EQUAL'), BinaryComparator.new(Bytes.toBytes('age')))}
ROW COLUMN+CELL
row-1 column=f:age, timestamp=1589252853542, value=20
row-2 column=f:age, timestamp=1589252853542, value=10
row-4 column=f:age, timestamp=1589252853542, value=Zhao
3 row(s) in 0.0400 seconds
支持的比较运算符：LESS、LESS_OR_EQUAL、EQUAL、NOT_EQUAL、GREATER、GREATER_OR_EQUAL，不再一一举例。
推荐使用方式一，更简洁方便。
2. BinaryPrefixComparator 构造过滤器
方式一：
hbase(main):011:0> scan 'test',{FILTER=>"QualifierFilter(=,'binaryprefix:nam')"}
ROW COLUMN+CELL
row-1 column=f:name, timestamp=1589252853542, value=Wang
row-2 column=f:name, timestamp=1589252853542, value=Zhou
row-3 column=f:name, timestamp=1589252853542, value=Li
row-4 column=f:namana, timestamp=1589252853542, value=xyz
4 row(s) in 0.0410 seconds
方式二：
import org.apache.hadoop.hbase.filter.CompareFilter
import org.apache.hadoop.hbase.filter.BinaryPrefixComparator
import org.apache.hadoop.hbase.filter.QualifierFilter
hbase(main):014:0> scan 'test',{FILTER => QualifierFilter.new(CompareFilter::CompareOp.valueOf('EQUAL'), BinaryPrefixComparator.new(Bytes.toBytes('nam')))}
ROW COLUMN+CELL
row-1 column=f:name, timestamp=1589252853542, value=Wang
row-2 column=f:name, timestamp=1589252853542, value=Zhou
row-3 column=f:name, timestamp=1589252853542, value=Li
row-4 column=f:namana, timestamp=1589252853542, value=xyz
4 row(s) in 0.0200 seconds
其它同上。
3. SubstringComparator 构造过滤器
方式一：
hbase(main):015:0> scan 'test',{FILTER=>"QualifierFilter(=,'substring:am')"}
ROW COLUMN+CELL
row-1 column=f:name, timestamp=1589252853542, value=Wang
row-2 column=f:name, timestamp=1589252853542, value=Zhou
row-3 column=f:name, timestamp=1589252853542, value=Li
row-4 column=f:namana, timestamp=1589252853542, value=xyz
4 row(s) in 0.0230 seconds
方式二：
import org.apache.hadoop.hbase.filter.CompareFilter
import org.apache.hadoop.hbase.filter.SubstringComparator
import org.apache.hadoop.hbase.filter.QualifierFilter
hbase(main):017:0> scan 'test',{FILTER => QualifierFilter.new(CompareFilter::CompareOp.valueOf('EQUAL'), SubstringComparator.new('am'))}
ROW COLUMN+CELL
row-1 column=f:name, timestamp=1589252853542, value=Wang
row-2 column=f:name, timestamp=1589252853542, value=Zhou
row-3 column=f:name, timestamp=1589252853542, value=Li
row-4 column=f:namana, timestamp=1589252853542, value=xyz
4 row(s) in 0.0220 seconds
区别于上的是这里直接传入字符串进行比较，且只支持EQUAL和NOT_EQUAL两种比较符。
4. RegexStringComparator 构造过滤器
import org.apache.hadoop.hbase.filter.CompareFilter
import org.apache.hadoop.hbase.filter.RegexStringComparator
import org.apache.hadoop.hbase.filter.QualifierFilter
hbase(main):019:0> scan 'test',{FILTER => QualifierFilter.new(CompareFilter::CompareOp.valueOf('EQUAL'), RegexStringComparator.new('n[a-z]m'))}
ROW COLUMN+CELL
row-1 column=f:name, timestamp=1589252853542, value=Wang
row-2 column=f:name, timestamp=1589252853542, value=Zhou
row-3 column=f:name, timestamp=1589252853542, value=Li
row-4 column=f:namana, timestamp=1589252853542, value=xyz
4 row(s) in 0.0250 seconds
该比较器直接传入字符串进行比较，且只支持EQUAL和NOT_EQUAL两种比较符。若想使用第一种方式可以传入regexstring试一下，我的版本有点低暂时不支持，不再演示了。
注意这里的正则匹配指包含关系，对应底层find()方法。
QualifierFilter 不支持使用LongComparator比较器，且BitComparator、NullComparator 比较器用之甚少，也不再介绍。
查看文章全部源代码请访以下GitHub地址：
https://github.com/zhoupengbo/demos-bigdata/blob/master/hbase/hbase-filters-demos/src/main/java/com/zpb/demos/QualifierFilterDemo.java
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