Hbase葱岭探秘--过滤器Api.doc

Hbase葱岭探秘-过滤器ApiHbase中提供了许多的过滤器接口，以此来对数据进行过滤，使得查询出想要的数据。行过滤器针对行信息进行过滤，参数中可以采用前缀匹配、按位与、或、异或以及子串匹配等匹配的方式。同时可以控制EQUAL、NOT_EQUAL选项进行控制筛选数据的条件。/* * 行过滤器 BinaryComparator NullComparator:是不是空值 * BitComparator:通过BitwiseOp类提供的按位与、或、异或操作进行位级别比较 RegexStringComparator:正则匹配 * SubStringComparator:子串是不是包含进行匹配 */ private static void testRowFilter() try HTable table = new HTable(config, testtable); Scan scan = new Scan(); scan.addColumn(col1.getBytes(), name.getBytes(); / 行过滤器 Filter filter = new RowFilter(CompareOp.EQUAL, new BinaryComparator(row2.getBytes(); scan.setFilter(filter); ResultScanner result = table.getScanner(scan); for (Result res : result) (行过滤器 + res); / 正则的行过滤器 Filter filter2 = new RowFilter(CompareOp.EQUAL, new RegexStringComparator(.*.2); scan.setFilter(filter2); ResultScanner resultRegx = table.getScanner(scan); for (Result res : resultRegx) (正则 + res); Filter filterSubString = new RowFilter(CompareOp.EQUAL, new SubstringComparator(w2); scan.setFilter(filterSubString); ResultScanner resultSubString = table.getScanner(scan); for (Result res : resultSubString) (子串 + res); table.close(); catch (IOException e) log.error(e); 列族过滤器根据列族的数据进行筛选，形式和上面的行过滤器类似，通过控制相应的参数中的筛选的条件进行相应的筛选。/* * 列族过滤器 */ private static void testFamlyFilter() try HTable table = new HTable(config, testtable); Filter filter = new FamilyFilter(CompareOp.EQUAL, new BinaryComparator(col1.getBytes(); Scan scan = new Scan(row2.getBytes(), filter); ResultScanner result = table.getScanner(scan); for (Result res : result) (res); Filter filterNull = new FamilyFilter(CompareOp.EQUAL, new RegexStringComparator(.*.1); Scan scanNull = new Scan(row2.getBytes(), filterNull); scanNull.addFamily(col1.getBytes(); ResultScanner resultNull = table.getScanner(scanNull); if (resultNull != null) for (Result res : resultNull) (res); else (null); table.close(); catch (IOException e) log.error(e); 列名过滤器和上面几个过滤器类似，这里是根据列进行筛选，设置相应的条件后就可以进行相应的筛选了。/* * 列名过滤器 */ public static void testColumFilter() try HTable table = new HTable(config, testtable); Filter filter = new QualifierFilter(CompareOp.EQUAL, new BinaryComparator(name.getBytes(); Scan scan = new Scan(row2.getBytes(), filter); ResultScanner result = table.getScanner(scan); for (Result res : result) (res); Get get = new Get(row2.getBytes(); get.setFilter(filter); Result resultGet = table.get(get); (resultGet); table.close(); catch (IOException e) (e); 参考列过滤器根据列族和列限定符进行筛选，返回与参考列相同时间戳的行的所有键值对。/* * 参考列过滤器 */ public static void testDependentColumnFilter() try HTable table = new HTable(config, testtable); Filter filter = new DependentColumnFilter(col1.getBytes(), name.getBytes(), false); Scan scan = new Scan(); scan.setFilter(filter); ResultScanner resu = table.getScanner(scan); for (Result result : resu) (result); Get get = new Get(row2.getBytes(); get.setFilter(filter); Result result = table.get(get); (result); table.close(); catch (IOException e) log.error(e); 单列过滤器通过一列的值进行判断是不是需要进行过滤。/* * 单列过滤器 */ public static void testSingleColumnValueFilter() try HTable table = new HTable(config, testtable); Filter filter = new SingleColumnValueFilter(col1.getBytes(), name.getBytes(), CompareOp.EQUAL, wy.getBytes(); Scan scan = new Scan(); scan.setFilter(filter); ResultScanner result = table.getScanner(scan); for (Result res : result) (res); Get get = new Get(row2.getBytes(); get.setFilter(filter); Result resultGet = table.get(get); (resultGet); table.close(); catch (IOException e) (e); 前缀过滤器根据前缀进行匹配行键的数据，本例中给出的是以row为前缀的行的数据。/* * 前缀过滤器 */ public static void testPrefixFilter() try HTable table = new HTable(config, testtable); Filter filter = new PrefixFilter(row.getBytes(); Scan scan = new Scan(); scan.setFilter(filter); ResultScanner result = table.getScanner(scan); for (Result res : result) (res + res); Get get = new Get(row2.getBytes(); Result resultGet = table.get(get); (get + resultGet); table.close(); catch (IOException e) (e); 分页过滤器通过pageFilter设置一页中数据的条数，注意，在重新设置起始行的时候，要使得新的行和数据库中有区别，否则，会死循环无法停止。/* * 分页过滤器 */ public static void testPageFilter() try HTable table = new HTable(config, testtable); Filter filter = new PageFilter(10); int totalRows = 0; byte lastRow = null; Scan scan = new Scan(); while (true) scan.setFilter(filter); if (lastRow != null) / 加上0后表示新的开始防止row的内容一样造成死循环 byte startRow = Bytes.add(lastRow, POSTFIX); scan.setStartRow(startRow); ResultScanner resultScan = table.getScanner(scan); int localRows = 0; Result result = resultScan.next(); while (result != null) (result); localRows+; totalRows+; lastRow = result.getRow(); result = resultScan.next(); if (localRows = 0) break; (totalRows); table.close(); catch (IOException e) (e); /* * 列分页过滤 */ public static void testColumnPaginationFilter() try HTable table = new HTable(config, testtable); Filter filter = new ColumnPaginationFilter(5, 10); Scan scan = new Scan(); scan.setFilter(filter); ResultScanner result = table.getScanner(scan); for (Result res : result) (res); table.close(); catch (IOException e) (e); Skip过滤器与ValueFilter结合使用，如果一行中某一列不符合要求的话直接被过滤掉。/* * 跳过过滤器 */ public static void testSkipFilter() try HTable table = new HTable(config, testtable); Filter filt = new ValueFilter(CompareOp.NOT_EQUAL, new BinaryComparator(v.getBytes(); Scan scanValue = new Scan(); scanVFilter(filt); ResultScanner ress = table.getScanner(scanValue); for (Result result : ress) ( + res); table.close(); catch (IOException e) (e); 全匹配过滤器在遇到某个条件之前的数据全部查询出来，直到遇到满足该条件的数据之后结束查询。 /* * 全匹配过滤器 */ public static void testWhileMatch() try HTable table = new HTable(config, testtable); Filter filt = new RowFilter(CompareOp.NOT_EQUAL, new BinaryComparator(row6.getBytes(); Scan scan = new Scan(); scan.setFilter(filt); ResultScanner results = table.getScanner(scan); for (Result res : results) ( + res); Filter filter = new WhileMatchFilter(filt); scan.setFlter(filter); ResultScanner resultScan = table.getScanner(scan); for (Result res : resultScan) ( + res); table.close(); catch (IOException e