引言：过滤器的类型很多，但是可以分为两大类——比较过滤器，专用过滤器
过滤器的作用是在服务端判断数据是否满足条件，然后只将满足条件的数据返回给客户端；
hbase过滤器的比较运算符：
LESS <
LESS_OR_EQUAL <=
EQUAL =
NOT_EQUAL <>
GREATER_OR_EQUAL >=
GREATER >
NO_OP 排除所有
Hbase过滤器的比较器（指定比较机制）：
BinaryComparator 按字节索引顺序比较指定字节数组，采用Bytes.compareTo(byte[])
BinaryPrefixComparator 跟前面相同，只是比较左端的数据是否相同
NullComparator 判断给定的是否为空
BitComparator 按位比较
RegexStringComparator 提供一个正则的比较器，仅支持 EQUAL 和非EQUAL
SubstringComparator 判断提供的子串是否出现在value中。
Hbase的过滤器分类
比较过滤器
1.1 行键过滤器RowFilter
Filter filter1 = new RowFilter(CompareOp.LESS_OR_EQUAL, new BinaryComparator(Bytes.toBytes("row-22")));
scan.setFilter(filter1);
1.2 列族过滤器FamilyFilter
Filter filter1 = new FamilyFilter(CompareFilter.CompareOp.LESS, new BinaryComparator(Bytes.toBytes("colfam3")));
scan.setFilter(filter1);
1.3 列过滤器QualifierFilter
filter = new QualifierFilter(CompareFilter.CompareOp.LESS_OR_EQUAL, new BinaryComparator(Bytes.toBytes("col-2")));
scan.setFilter(filter1);
1.4 值过滤器 ValueFilter
Filter filter = new ValueFilter(CompareFilter.CompareOp.EQUAL, new SubstringComparator(".4") );
scan.setFilter(filter1);
专用过滤器
2.1 单列值过滤器 SingleColumnValueFilter ----会返回满足条件的整行
SingleColumnValueFilter filter = new SingleColumnValueFilter(
Bytes.toBytes("colfam1"),
Bytes.toBytes("col-5"),
CompareFilter.CompareOp.NOT_EQUAL,
new SubstringComparator("val-5"));
filter.setFilterIfMissing(true); //如果不设置为true，则那些不包含指定column的行也会返回
scan.setFilter(filter1);
2.2 SingleColumnValueExcludeFilter
与上相反
2.3 前缀过滤器 PrefixFilter----针对行键
Filter filter = new PrefixFilter(Bytes.toBytes("row1"));
scan.setFilter(filter1);
2.4 列前缀过滤器 ColumnPrefixFilter
Filter filter = new ColumnPrefixFilter(Bytes.toBytes("qual2"));
scan.setFilter(filter1);
2.4分页过滤器 PageFilter
public static void main(String[] args) throws Exception {
Configuration conf = HBaseConfiguration.create();
conf.set("hbase.zookeeper.quorum", "spark01:2181,spark02:2181,spark03:2181");
String tableName = "testfilter";
String cfName = "f1";
final byte[] POSTFIX = new byte[] { 0x00 };
HTable table = new HTable(conf, tableName);
Filter filter = new PageFilter(3);
byte[] lastRow = null;
int totalRows = 0;
while (true) {
Scan scan = new Scan();
scan.setFilter(filter);
if(lastRow != null){
//注意这里添加了POSTFIX操作，用来重置扫描边界
byte[] startRow = Bytes.add(lastRow,POSTFIX);
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);
}
/**
* 多种过滤条件的使用方法
* @throws Exception
*/
@Test
public void testScan() throws Exception{
HTable table = new HTable(conf, "person_info".getBytes());