Hbase DependentColumnFilter

Here you have a more complex filter that does not simply filter out data based on directly available information. Rather, it lets you specify a dependent column—or reference column—that controls how other columns are filtered. It uses th

Here you have a more complex filter that does not simply filter out data based on
directly available information. Rather, it lets you specify a dependent column—or
reference column—that controls how other columns are filtered. It uses the timestamp
of the reference column and includes all other columns that have the same timestamp.

尝试找到该列所在的每一行，并返回该行具有相同时间戳的全部键值对。如果某一行不包含指定的列，则该行的任何键值对都不返回。
如果dropDependentColumn=true，则从属列不返回。

via: http://abloz.com/2012/08/22/the-hbases-content-query-2.html

package com.fatkun.filter.comparison;import java.io.IOException;import org.apache.hadoop.conf.Configuration;import org.apache.hadoop.hbase.HBaseConfiguration;import org.apache.hadoop.hbase.HColumnDescriptor;import org.apache.hadoop.hbase.HTableDescriptor;import org.apache.hadoop.hbase.KeyValue;import org.apache.hadoop.hbase.client.Get;import org.apache.hadoop.hbase.client.HBaseAdmin;import org.apache.hadoop.hbase.client.HTable;import org.apache.hadoop.hbase.client.Put;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.BinaryPrefixComparator;import org.apache.hadoop.hbase.filter.CompareFilter;import org.apache.hadoop.hbase.filter.DependentColumnFilter;import org.apache.hadoop.hbase.filter.Filter;import org.apache.hadoop.hbase.filter.SubstringComparator;import org.apache.hadoop.hbase.filter.ValueFilter;import org.apache.hadoop.hbase.filter.WritableByteArrayComparable;import org.apache.hadoop.hbase.util.Bytes;public class TestHbaseDependentColumnFilter {    String tableName = "test_value_filter";    Configuration config = HBaseConfiguration.create();    public void filter&#<i style="color:transparent">本文来源gaodai$ma#com搞$$代**码网$</i>40;boolean drop, CompareFilter.CompareOp operator,            WritableByteArrayComparable comparator) throws IOException {        HTable table = new HTable(config, tableName);        //        Filter filter;        if (comparator != null) {            // drop为true时，filter表示对"col1"列以外的所有"data1"列族数据做filter操作            // drop为false时,表示对所有"data1"列族的数据做filter操作            filter = new DependentColumnFilter(Bytes.toBytes("data1"),                    Bytes.toBytes("col1"), drop, operator, comparator);        } else {            filter = new DependentColumnFilter(Bytes.toBytes("data1"),                    Bytes.toBytes("col1"), drop);        }        // filter应用于scan        Scan scan = new Scan();        scan.setFilter(filter);        ResultScanner scanner = table.getScanner(scan);        for (Result result : scanner) {            for (KeyValue kv : result.list()) {                System.out.println("kv=" + kv.toString() + ",value="                        + Bytes.toString(kv.getValue()));            }        }        scanner.close();        table.close();    }    /**     * 部分代码来自hbase权威指南     *      * @throws IOException     */    public void testFilter() throws IOException {        // The dropDependentColumn parameter is giving you additional control        // over how the reference column is handled: it is either included or        // dropped by the filter        // 1.获取整个"data1"列族当前Version中的所有timestamp等于参照列"data1:col1"的数据        System.out.println("drop=false");        filter(false, CompareFilter.CompareOp.NO_OP, null);        // 2.获取除了"col1"列以外的"data1"列族中的所有timestamp等于参照列"data1:col1"的数据        System.out.println("drop=true");        filter(true, CompareFilter.CompareOp.NO_OP, null);        // 3.获取除了"col1"列以外的"data1"列族当前Version中的所有timestamp等于参照列"data1:col1"的,value以"data100"开头的所有数据        System.out.println("比较");        filter(true, CompareFilter.CompareOp.EQUAL, new BinaryPrefixComparator(                Bytes.toBytes("data100")));    }    /**     * 初始化数据     */    public void init() {        // 创建表和初始化数据        try {            HBaseAdmin admin = new HBaseAdmin(config);            if (!admin.tableExists(tableName)) {                HTableDescriptor htd = new HTableDescriptor(tableName);                HColumnDescriptor hcd1 = new HColumnDescriptor("data1");                htd.addFamily(hcd1);                HColumnDescriptor hcd2 = new HColumnDescriptor("data2");                htd.addFamily(hcd2);                HColumnDescriptor hcd3 = new HColumnDescriptor("data3");                htd.addFamily(hcd3);                admin.createTable(htd);            }            HTable table = new HTable(config, tableName);            table.setAutoFlush(false);            int count = 50;            for (int i = 1; i <= count; ++i) {                Put p = new Put(String.format("row%03d", i).getBytes());                p.add("data1".getBytes(), String.format("col%01d", i % 10)                        .getBytes(), String.format("data1%03d", i).getBytes());                p.add("data2".getBytes(), String.format("col%01d", i % 10)                        .getBytes(), String.format("data2%03d", i).getBytes());                p.add("data3".getBytes(), String.format("col%01d", i % 10)                        .getBytes(), String.format("data3%03d", i).getBytes());                table.put(p);            }            table.close();        } catch (IOException e) {            e.printStackTrace();        }    }    /**     * @param args     * @throws IOException     */    public static void main(String[] args) throws IOException {        TestHbaseDependentColumnFilter test = new TestHbaseDependentColumnFilter();        test.init();        test.testFilter();    }}

原文地址：Hbase DependentColumnFilter, 感谢原作者分享。

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