HBASE过滤器
HBase过滤器
作用
- 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
- 过滤器的类型很多，但是可以分为两大类：
- 比较过滤器：可应用于rowkey、列簇、列、列值过滤器
- 专用过滤器：只能适用于特定的过滤器
比较过滤器
比较运算符
-
LESS <
-
LESS_OR_EQUAL <=
-
EQUAL =
-
NOT_EQUAL <>
-
GREATER_OR_EQUAL >=
-
GREATER >
-
NO_OP 排除所有
常见的六大比较过滤器
BinaryComparator
按字节索引顺序比较指定字节数组，采用Bytes.compareTo(byte[])
BinaryPrefixComparator
通BinaryComparator，只是比较左端前缀的数据是否相同
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中
示例代码
rowKey过滤器：RowFilter
通过RowFilter与BinaryComparator过滤比rowKey 1500100010小的所有值出来
@Test
// 通过RowFilter过滤比rowKey 1500100010 小的所有值出来
public void BinaryComparatorFilter() throws IOException {
Table students = conn.getTable(TableName.valueOf("students"));
BinaryComparator binaryComparator = new BinaryComparator(Bytes.toBytes(1500100010));
RowFilter rowFilter = new RowFilter(CompareFilter.CompareOp.LESS, binaryComparator);
Scan scan = new Scan();
scan.setFilter(rowFilter);
ResultScanner scanner = students.getScanner(scan);
Result rs = scanner.next();
while (rs != null) {
String id = Bytes.toString(rs.getRow());
String name = Bytes.toString(rs.getValue("info".getBytes(), "name".getBytes()));
int age = Bytes.toInt(rs.getValue("info".getBytes(), "age".getBytes()));
String gender = Bytes.toString(rs.getValue("info".getBytes(), "gender".getBytes()));
String clazz = Bytes.toString(rs.getValue("info".getBytes(), "clazz".getBytes()));
System.out.println(id + "\t" + name + "\t" + age + "\t" + gender + "\t" + clazz + "\t");
rs = scanner.next();
}
}
列簇过滤器：FamilyFilter
通过FamilyFilter与SubstringComparator查询列簇名包含in的所有列簇下面的数据
@Test
// 通过FamilyFilter查询列簇名包含in的所有列簇下面的数据
public void SubstringComparatorFilter() throws IOException {
Table students = conn.getTable(TableName.valueOf("students"));
SubstringComparator substringComparator = new SubstringComparator("in");
FamilyFilter familyFilter = new FamilyFilter(CompareFilter.CompareOp.EQUAL, substringComparator);
Scan scan = new Scan();
scan.setFilter(familyFilter);
ResultScanner scanner = students.getScanner(scan);
Result rs = scanner.next();
while (rs != null) {
String id = Bytes.toString(rs.getRow());
String name = Bytes.toString(rs.getValue("info".getBytes(), "name".getBytes()));
int age = Bytes.toInt(rs.getValue("info".getBytes(), "age".getBytes()));
String gender = Bytes.toString(rs.getValue("info".getBytes(), "gender".getBytes()));
String clazz = Bytes.toString(rs.getValue("info".getBytes(), "clazz".getBytes()));
System.out.println(id + "\t" + name + "\t" + age + "\t" + gender + "\t" + clazz + "\t");
rs = scanner.next();
}
}
通过FamilyFilter与 BinaryPrefixComparator 过滤出列簇以info开头的列簇下的所有数据
// 通过FamilyFilter与 BinaryPrefixComparator 过滤出列簇以info开头的所有列簇下的所有数据
@Test
public void BinaryPrefixComparatorFilter() throws IOException {
Table students = conn.getTable(TableName.valueOf("students"));
// 二进制前缀比较器
BinaryPrefixComparator binaryPrefixComparator = new BinaryPrefixComparator("info".getBytes());
// FamilyFilter 作用于列簇的过滤器
FamilyFilter familyFilter = new FamilyFilter(CompareFilter.CompareOp.EQUAL, binaryPrefixComparator);
Scan scan = new Scan();
scan.withStartRow("1500100001".getBytes());
scan.withStopRow("1500100011".getBytes());
// 通过setFilter方法设置过滤器
scan.setFilter(familyFilter);
ResultScanner scanner = students.getScanner(scan);
printRS(scanner);
}
列过滤器：QualifierFilter
通过QualifierFilter与SubstringComparator查询列名包含in的列的值
public void printRS(ResultScanner scanner) throws IOException {
for (Result rs : scanner) {
String rowkey = Bytes.toString(rs.getRow());
System.out.println("当前行的rowkey为：" + rowkey);
for (Cell cell : rs.listCells()) {
String family = Bytes.toString(CellUtil.cloneFamily(cell));
String qualifier = Bytes.toString(CellUtil.cloneQualifier(cell));
byte[] bytes = CellUtil.cloneValue(cell);
if ("age".equals(qualifier)) {
int value = Bytes.toInt(bytes);
System.out.println(family + ":" + qualifier + "的值为" + value);
} else {
String value = Bytes.toString(bytes);
System.out.println(family + ":" + qualifier + "的值为" + value);
}
}
}
}
@Test
// 通过FamilyFilter查询列簇名包含in的所有列簇下面的数据
public void SubstringComparatorFilter() throws IOException {
Table students = conn.getTable(TableName.valueOf("students"));
SubstringComparator substringComparator = new SubstringComparator("in");
FamilyFilter familyFilter = new FamilyFilter(CompareFilter.CompareOp.EQUAL, substringComparator);
Scan scan = new Scan();
scan.setFilter(familyFilter);
ResultScanner scanner = students.getScanner(scan);
Result rs = scanner.next();
while (rs != null) {
String id = Bytes.toString(rs.getRow());
String name = Bytes.toString(rs.getValue("info".getBytes(), "name".getBytes()));
int age = Bytes.toInt(rs.getValue("info".getBytes(), "age".getBytes()));
String gender = Bytes.toString(rs.getValue("info".getBytes(), "gender".getBytes()));
String clazz = Bytes.toString(rs.getValue("info".getBytes(), "clazz".getBytes()));
System.out.println(id + "\t" + name + "\t" + age + "\t" + gender + "\t" + clazz + "\t");
rs = scanner.next();
}
}
过滤出 列的名字 中 包含 "am" 所有的列 及列的值
// 过滤出 列的名字 中 包含 "am" 所有的列 及列的值
@Test
public void SubstringComparatorQualifierFilter() throws IOException {
Table students = conn.getTable(TableName.valueOf("students"));
SubstringComparator substringComparator = new SubstringComparator("am");
// 作用在列名上的过滤器
QualifierFilter qualifierFilter = new QualifierFilter(CompareFilter.CompareOp.EQUAL, substringComparator);
Scan scan = new Scan();
scan.withStartRow("1500100001".getBytes());
scan.withStopRow("1500100011".getBytes());
// 通过setFilter方法设置过滤器
scan.setFilter(qualifierFilter);
ResultScanner scanner = students.getScanner(scan);
printRS(scanner);
}
列值过滤器：ValueFilter
通过ValueFilter与BinaryPrefixComparator过滤出所有的cell中值以 "张" 开头的学生
@Test
// 通过ValueFilter与BinaryPrefixComparator过滤出所有的cell中值以 "张" 开头的学生
public void BinaryPrefixComparatorFilter() throws IOException {
Table students = conn.getTable(TableName.valueOf("students"));
BinaryPrefixComparator binaryPrefixComparator = new BinaryPrefixComparator("张".getBytes());
ValueFilter valueFilter = new ValueFilter(CompareFilter.CompareOp.EQUAL, binaryPrefixComparator);
Scan scan = new Scan();
scan.setFilter(valueFilter);
ResultScanner scanner = students.getScanner(scan);
printRS(scanner);
}
过滤出文科的学生，只会返回clazz列，其他列的数据不符合条件，不会返回
// 过滤出文科的学生
// 只会返回clazz列，其他列的数据不符合条件，不会返回
@Test
public void RegexStringComparatorFilter() throws IOException {
Table students = conn.getTable(TableName.valueOf("students"));
// 使用正则表达式比较器
RegexStringComparator regexStringComparator = new RegexStringComparator("^文科.*");
// ValueFilter 会返回符合条件的cell，并不会返回整条数据
ValueFilter valueFilter = new ValueFilter(CompareFilter.CompareOp.EQUAL, regexStringComparator);
Scan scan = new Scan();
scan.withStartRow("1500100001".getBytes());
scan.withStopRow("1500100011".getBytes());
// 通过setFilter方法设置过滤器
scan.setFilter(valueFilter);
ResultScanner scanner = students.getScanner(scan);
printRS(scanner);
}
专用过滤器
单列值过滤器：SingleColumnValueFilter
SingleColumnValueFilter会返回满足条件的cell所在行的所有cell的值（即会返回一行数据）
通过SingleColumnValueFilter与查询文科班所有学生信息
@Test
// 通过SingleColumnValueFilter与查询文科班所有学生信息
public void RegexStringComparatorFilter() throws IOException {
Table students = conn.getTable(TableName.valueOf("students"));
SingleColumnValueFilter singleColumnValueFilter = new SingleColumnValueFilter(
"info".getBytes(),
"clazz".getBytes(),
CompareFilter.CompareOp.EQUAL,
new RegexStringComparator("^文科.*")
);
Scan scan = new Scan();
scan.setFilter(singleColumnValueFilter);
ResultScanner scanner = students.getScanner(scan);
Result rs = scanner.next();
while (rs != null) {
String id = Bytes.toString(rs.getRow());
String name = Bytes.toString(rs.getValue("info".getBytes(), "name".getBytes()));
int age = Bytes.toInt(rs.getValue("info".getBytes(), "age".getBytes()));
String gender = Bytes.toString(rs.getValue("info".getBytes(), "gender".getBytes()));
String clazz = Bytes.toString(rs.getValue("info".getBytes(), "clazz".getBytes()));
System.out.println(id + "\t" + name + "\t" + age + "\t" + gender + "\t" + clazz + "\t");
rs = scanner.next();
}
}
列值排除过滤器：SingleColumnValueExcludeFilter
与SingleColumnValueFilter相反，会排除掉指定的列，其他的列全部返回
通过SingleColumnValueExcludeFilter与BinaryComparator查询文科一班所有学生信息，最终不返回clazz列
@Test // 通过SingleColumnValueExcludeFilter与BinaryComparator查询文科一班所有学生信息，最终不返回clazz列 public void RegexStringComparatorExcludeFilter() throws IOException { Table students = conn.getTable(TableName.valueOf("students")); SingleColumnValueExcludeFilter singleColumnValueExcludeFilter = new SingleColumnValueExcludeFilter( "info".getBytes(), "clazz".getBytes(), CompareFilter.CompareOp.EQUAL, new BinaryComparator("文科一班".getBytes()) ); Scan scan = new Scan(); scan.setFilter(singleColumnValueExcludeFilter); ResultScanner scanner = students.getScanner(scan); Result rs = scanner.next(); while (rs != null) { String id = Bytes.toString(rs.getRow()); String name = Bytes.toString(rs.getValue("info".getBytes(), "name".getBytes())); int age = Bytes.toInt(rs.getValue("info".getBytes(), "age".getBytes())); String gender = Bytes.toString(rs.getValue("info".getBytes(), "gender".getBytes())); // clazz列为空 String clazz = Bytes.toString(rs.getValue("info".getBytes(), "clazz".getBytes())); System.out.println(id + "\t" + name + "\t" + age + "\t" + gender + "\t" + clazz + "\t"); rs = scanner.next(); } }
rowkey前缀过滤器：PrefixFilter
通过PrefixFilter查询以150010008开头的所有前缀的rowkey
@Test // 通过PrefixFilter查询以150010008开头的所有前缀的rowkey public void PrefixFilterFilter() throws IOException { Table students = conn.getTable(TableName.valueOf("students")); PrefixFilter prefixFilter = new PrefixFilter("150010008".getBytes()); Scan scan = new Scan(); scan.setFilter(prefixFilter); ResultScanner scanner = students.getScanner(scan); Result rs = scanner.next(); while (rs != null) { String id = Bytes.toString(rs.getRow()); String name = Bytes.toString(rs.getValue("info".getBytes(), "name".getBytes())); int age = Bytes.toInt(rs.getValue("info".getBytes(), "age".getBytes())); String gender = Bytes.toString(rs.getValue("info".getBytes(), "gender".getBytes())); // clazz列为空 String clazz = Bytes.toString(rs.getValue("info".getBytes(), "clazz".getBytes())); System.out.println(id + "\t" + name + "\t" + age + "\t" + gender + "\t" + clazz + "\t"); rs = scanner.next(); } }
分页过滤器PageFilter
通过PageFilter查询第三页的数据，每页10条
使用PageFilter分页效率比较低，每次都需要扫描前面的数据，直到扫描到所需要查的数据
可设计一个合理的rowkey来实现分页需求
@Test // 通过PageFilter查询第三页的数据，每页10条 public void PageFilter() throws IOException { Table students = conn.getTable(TableName.valueOf("students")); int PageNum = 3; int PageSize = 10; Scan scan = new Scan(); if (PageNum == 1) { scan.withStartRow("".getBytes()); //使用分页过滤器，实现数据的分页 PageFilter pageFilter = new PageFilter(PageSize); scan.setFilter(pageFilter); ResultScanner scanner = students.getScanner(scan); printRS(scanner); } else { String current_page_start_rows = ""; int scanDatas = (PageNum - 1) * PageSize + 1; PageFilter pageFilter = new PageFilter(scanDatas); scan.setFilter(pageFilter); ResultScanner scanner = students.getScanner(scan); for (Result rs : scanner) { current_page_start_rows = Bytes.toString(rs.getRow()); } scan.withStartRow(current_page_start_rows.getBytes()); PageFilter pageFilter1 = new PageFilter(PageSize); scan.setFilter(pageFilter1); ResultScanner scanner1 = students.getScanner(scan); printRS(scanner1); } }
通过合理的设置rowkey来实现分页功能
@Test // 通过合理的设置rowkey来实现分页功能，提高效率 public void PageFilterTest2() throws IOException { Table students = conn.getTable(TableName.valueOf("students")); int PageSize = 10; int PageNum = 3; int baseId = 1500100000; int start_row = baseId + (PageNum - 1) * PageSize + 1; int end_row = start_row + PageSize; Scan scan = new Scan(); scan.withStartRow(String.valueOf(start_row).getBytes()); scan.withStopRow(String.valueOf(end_row).getBytes()); ResultScanner scanner = students.getScanner(scan); printRS(scanner); }
多过滤器综合查询
查询文科班中的学生中学号以150010008开头并且年龄小于23的学生信息
@Test // 查询文科班中的学生中学号以150010008开头并且年龄小于23的学生信息 public void FilterListFilter() throws IOException { Table students = conn.getTable(TableName.valueOf("students")); Scan scan = new Scan(); SingleColumnValueFilter singleColumnValueFilter = new SingleColumnValueFilter( "info".getBytes() , "clazz".getBytes() , CompareFilter.CompareOp.EQUAL , new RegexStringComparator("^文科.*")); PrefixFilter prefixFilter = new PrefixFilter("150010008".getBytes()); SingleColumnValueFilter singleColumnValueFilter1 = new SingleColumnValueFilter( "info".getBytes() , "age".getBytes() , CompareFilter.CompareOp.LESS , new BinaryComparator(Bytes.toBytes(23))); FilterList filterList = new FilterList(); filterList.addFilter(singleColumnValueFilter); filterList.addFilter(prefixFilter); filterList.addFilter(singleColumnValueFilter1); scan.setFilter(filterList); ResultScanner scanner = students.getScanner(scan); printRS(scanner); }
