Hbase 学习（二）各种filter

各种filter 今天的主题是Filter，hbase客户端查询的时候，自定义查询filter。 直接上例子吧，不多说别的了，第一个例子是RowFilter的。

Scan scan = new Scan(); scan.addColumn(Bytes.toBytes("colfam1"), Bytes.toBytes("col-0")); Filter filter1 = new RowFilter(CompareFilter.CompareOp.LESS_OR_EQUAL, new BinaryComparator(Bytes.toBytes("row-22"))); scan.setFilter(filter1); ResultScanner scanner1 = table.getScanner(scan); for (Result res : scanner1) { System.out.println(res); } scanner1.close(); Filter filter2 = new RowFilter(CompareFilter.CompareOp.EQUAL, new RegexStringComparator(".*-.5")); scan.setFilter(filter2); ResultScanner scanner2 = table.getScanner(scan); for (Result res : scanner2) { System.out.println(res); } scanner2.close(); Filter filter3 = new RowFilter(CompareFilter.CompareOp.EQUAL, new SubstringComparator("-5")); scan.setFilter(filter3); ResultScanner scanner3 = table.getScanner(scan); for (Result res : scanner3) { System.out.println(res); } scanner3.close();

第二个例子是QualifierFilter的

Filter filter = new QualifierFilter(CompareFilter.CompareOp.LESS_OR_EQUAL, new BinaryComparator(Bytes.toBytes("col-2"))); Scan scan = new Scan(); scan.setFilter(filter); ResultScanner scanner = table.getScanner(scan); for (Result result : scanner) { System.out.println(result); } scanner.close(); Get get = new Get(Bytes.toBytes("row-5")); get.setFilter(filter); Result result = table.get(get);

第三个例子是ValueFilter

Filter filter = new ValueFilter(CompareFilter.CompareOp.EQUAL, new SubstringComparator(".4")); Scan scan = new Scan(); scan.setFilter(filter); ResultScanner scanner = table.getScanner(scan); for (Result result : scanner) { for (KeyValue kv : result.raw()) { System.out.println("KV: " + kv + ", Value: " + Bytes.toString(kv.getValue())); } } scanner.close(); Get get = new Get(Bytes.toBytes("row-5")); get.setFilter(filter); Result result = table.get(get); for (KeyValue kv : result.raw()) { System.out.println("KV: " + kv + ", Value: " + Bytes.toString(kv.getValue())); }

第四个例子是PageFilter，分页的filter

Filter filter = new PageFilter(15); int totalRows = 0; byte[] lastRow = null; while (true) { Scan scan = new Scan(); scan.setFilter(filter); if (lastRow != null) { byte[] startRow = Bytes.add(lastRow, POSTFIX); System.out.println("start row: " +Bytes.toStringBinary(startRow)); scan.setStartRow(startRow); } ResultScanner scanner = table.getScanner(scan); int localRows = 0; Result result; while ((result = scanner.next()) != null) { System.out.println(localRows++ + ": " + result); totalRows++; lastRow = result.getRow(); } scanner.close(); if (localRows == 0) break; } System.out.println("total rows: " + totalRows);

第五个例子是InclusiveStopFilter，它是什么意思呢，就是扫描到某个rowkey就停止，下面的例子是从row-3开始扫描，一直扫描到row-5结束。

Filter filter = new InclusiveStopFilter(Bytes.toBytes("row-5")); Scan scan = new Scan(); scan.setStartRow(Bytes.toBytes("row-3")); scan.setFilter(filter); ResultScanner scanner = table.getScanner(scan); for (Result result : scanner) { System.out.println(result); } scanner.close();

第六个SingleColumnValueFilter，这个是我们最常用的filter，我觉得很好用。

SingleColumnValueFilter filter = new SingleColumnValueFilter(Bytes.toBytes("colfam1"), Bytes.toBytes("col-5"), CompareFilter.CompareOp.NOT_EQUAL, new SubstringComparator("val-5")); filter.setFilterIfMissing(true); Scan scan = new Scan(); scan.setFilter(filter); ResultScanner scanner = table.getScanner(scan); for (Result result : scanner) { for (KeyValue kv : result.raw()) { System.out.println("KV: " + kv + ", Value: " + Bytes.toString(kv.getValue())); } } scanner.close(); Get get = new Get(Bytes.toBytes("row-6")); get.setFilter(filter); Result result = table.get(get); System.out.println("Result of get: "); for (KeyValue kv : result.raw()) { System.out.println("KV: " + kv + ", Value: " + Bytes.toString(kv.getValue())); }

第七个FilterList，它有两个选项，需要全部通过，还是一个通过就行，MUST_PASS_ALL，MUST_PASS_ONE。

List<Filter> filters = new ArrayList<Filter>(); Filter filter1 = new RowFilter(CompareFilter.CompareOp.GREATER_OR_EQUAL, new BinaryComparator(Bytes.toBytes("row-03"))); filters.add(filter1); 302 Filter filter2 = new RowFilter(CompareFilter.CompareOp.LESS_OR_EQUAL, new BinaryComparator(Bytes.toBytes("row-06"))); filters.add(filter2); Filter filter3 = new QualifierFilter(CompareFilter.CompareOp.EQUAL, new RegexStringComparator("col-0[03]")); filters.add(filter3); FilterList filterList1 = new FilterList(filters); Scan scan = new Scan(); scan.setFilter(filterList1); ResultScanner scanner1 = table.getScanner(scan); for (Result result : scanner1) { for (KeyValue kv : result.raw()) { System.out.println("KV: " + kv + ", Value: " + Bytes.toString(kv.getValue())); } } scanner1.close(); FilterList filterList2 = new FilterList( FilterList.Operator.MUST_PASS_ONE, filters); scan.setFilter(filterList2); ResultScanner scanner2 = table.getScanner(scan); for (Result result : scanner2) { for (KeyValue kv : result.raw()) { System.out.println("KV: " + kv + ", Value: " + Bytes.toString(kv.getValue())); } } scanner2.close();