HBase高级特性：过滤器（一）
第1关：使用过滤器查询指定行的数据知识点
1.使用过滤器的步骤：
（1）创建过滤器：RowFilter(CompareOperator op,ByteArrayComparable rowComparator)，第一个参数接收的是比力操尴尬刁难象，第二个参数接收的是条件。
第一个参数有很多种取值以匹配多种场景，取值表格如下：
操作描述CompareOperator.LESS匹配小于设定值的值CompareOperator.LESS_OR_EQUAL匹配小于或等于设定值的值CompareOperator.EQUAL匹配等于设定值的值CompareOperator.NOT_EQUAL匹配与设定值不相等的值CompareOperator.GREATER_OR_EQUAL匹配大于或等于设定值的值CompareOperator.GREATER匹配大于设定值的值CompareOperator.NO_OP排除一切值 （2）设置过滤器。
编程要求
请补全函数query(String tName)，需要你查询的数据如下，表名会作为方法的参数传入：
[*] 查询basic_info列族gender列，且行键为2018的值；
[*] 查询school_info列族college列，且行键大于2018的值；
[*] 查询basic_info列族name列，且行键小于等于2020的值。
package step1;
import java.io.IOException;
import org.apache.hadoop.cli.util.*;
import org.apache.hadoop.conf.*;
import org.apache.hadoop.hbase.*;
import org.apache.hadoop.hbase.client.*;
import org.apache.hadoop.hbase.filter.*;
import org.apache.hadoop.hbase.util.*;
public class Task {
public void query(String tName) throws Exception {
/********* Begin *********/
Configuration config = new Configuration();
Connection conn = ConnectionFactory.createConnection(config);
TableName tableName = TableName.valueOf(tName);
Table table = conn.getTable(tableName);
Scan scan1=new Scan();
scan1.addColumn(Bytes.toBytes("basic_info"), Bytes.toBytes("gender"));
Filter filter1 = new RowFilter(CompareOperator.EQUAL,new BinaryComparator(Bytes.toBytes("2018")));
scan1.setFilter(filter1);
ResultScanner scanner1 = table.getScanner(scan1);
System.out.println("row:2018");
for (Result result : scanner1) {
for(Cell cell : result.listCells()){
System.out.println("basic_info:gender " + new String(CellUtil.cloneValue(cell),"utf-8") );
}
}
scanner1.close();
Scan scan2=new Scan();
scan2.addColumn(Bytes.toBytes("school_info"), Bytes.toBytes("college"));
Filter filter2 = new RowFilter(CompareOperator.GREATER,new BinaryComparator(Bytes.toBytes("2018")));
scan2.setFilter(filter2);
ResultScanner scanner2 = table.getScanner(scan2);
for (Result result : scanner2) {
System.out.println("row:" + new String(result.getRow(),"utf-8"));
for(Cell cell : result.listCells()){
System.out.println("school_info:college " + new String(CellUtil.cloneValue(cell),"utf-8") );
}
}
scanner2.close();
Scan scan3=new Scan();
scan3.addColumn(Bytes.toBytes("basic_info"), Bytes.toBytes("name"));
Filter filter3 = new RowFilter(CompareOperator.LESS_OR_EQUAL,new BinaryComparator(Bytes.toBytes("2020")));
scan3.setFilter(filter3);
ResultScanner scanner3 = table.getScanner(scan3);
for (Result result : scanner3) {
System.out.println("row:" + new String(result.getRow(),"utf-8"));
for(Cell cell : result.listCells()){
System.out.println("basic_info:name " + new String(CellUtil.cloneValue(cell),"utf-8") );
}
}
scanner3.close();
conn.close();
/********* End *********/
}
} 第2关：使用正则表达式与子字符串匹配行键
知识点
比力器的子类
比力器描述BinaryComparator使用Bytes.compareTo()比力当前值与阈值BinaryPrefixComparator与上面类似，但是是从左端开始前缀匹配NullComparator不做匹配，只判定当前值是不是nullBitComparator通过BitwiseOp类提供的按位与（AND）、或（OR）、异或（XOR）操作执行位级比力RegexStringComparator（正则比力器）根据一个正则表达式，在实例化这个比力器的时间去匹配表中的数据SubStringComparator（子串过滤器）把阈值和表中数据当做String实例，同时通过contains()操作匹配字符串 编程要求
查询表t2_student_table中的数据。 要求如下：
[*] 查询以1开头，并以9末端的行键，并输出该行所有列的值；
[*] 查询包含231的行键，并输出该行所有列的值。
package step2;
import java.io.IOException;
import org.apache.hadoop.cli.util.*;
import org.apache.hadoop.conf.*;
import org.apache.hadoop.hbase.*;
import org.apache.hadoop.hbase.client.*;
import org.apache.hadoop.hbase.filter.*;
import org.apache.hadoop.hbase.util.*;
import org.apache.hadoop.hbase.filter.SubstringComparator;
public class Task {
public void query() throws Exception {
/********* Begin *********/
Configuration config = new Configuration();
Connection conn = ConnectionFactory.createConnection(config);
TableName tablename=TableName.valueOf("t2_student_table");
Table table=conn.getTable(tablename);
Scan scan1=new Scan();
Filter filter1 = new RowFilter(CompareOperator.EQUAL,new RegexStringComparator("1.*9$")); //查询以1开头，并以9结尾的行键
scan1.setFilter(filter1);
ResultScanner scanner1 = table.getScanner(scan1);
for (Result result : scanner1) {
System.out.println("row:" + new String(result.getRow(),"utf-8"));
for(Cell cell : result.listCells()){
String family = Bytes.toString(CellUtil.cloneFamily(cell));
String qualifier = Bytes.toString(CellUtil.cloneQualifier(cell));
String value = Bytes.toString(CellUtil.cloneValue(cell));
System.out.println(family + ":" + qualifier + " " + value);
}
}
scanner1.close();
Scan scan2=new Scan();
Filter filter2 = new RowFilter(CompareOperator.EQUAL,new SubstringComparator("231")); //查询包含231的行键
scan2.setFilter(filter2);
ResultScanner scanner2 = table.getScanner(scan2);
for (Result result : scanner2) {
System.out.println("row:" + new String(result.getRow(),"utf-8"));
for(Cell cell : result.listCells()){
String family = Bytes.toString(CellUtil.cloneFamily(cell));
String qualifier = Bytes.toString(CellUtil.cloneQualifier(cell));
String value = Bytes.toString(CellUtil.cloneValue(cell));
System.out.println(family + ":" + qualifier + " " + value);
}
}
scanner2.close();
conn.close();
/********* End *********/
}
} 第3关：列族过滤器、值过滤器、列名过滤器
编程要求
使用过滤器对表t3_student_table完成如下查询操作：
[*] 查询行键1019中列族school_info所有列，输出值；
[*] 查询行键2020中，列名包含字母c的所有列，输出值；
[*] 查询表所有行中包含张的值，并输出该值。
package step3;
import java.io.IOException;
import org.apache.hadoop.cli.util.*;
import org.apache.hadoop.conf.*;
import org.apache.hadoop.hbase.*;
import org.apache.hadoop.hbase.client.*;
import org.apache.hadoop.hbase.filter.*;
import org.apache.hadoop.hbase.util.*;
import org.apache.hadoop.hbase.filter.SubstringComparator;
public class Task {
public void query() throws Exception {
/********* Begin *********/
Configuration config = new Configuration();
Connection conn = ConnectionFactory.createConnection(config);
TableName tableName = TableName.valueOf(Bytes.toBytes("t3_student_table"));
Table table = conn.getTable(tableName);
Filter filter1 = new FamilyFilter(CompareOperator.EQUAL,new BinaryComparator(Bytes.toBytes("school_info")));//列族过滤器
Get get1 = new Get(Bytes.toBytes("1019"));
get1.setFilter(filter1);
Result result1 = table.get(get1);
System.out.println("row:" + new String(result1.getRow(),"utf-8"));
for(Cell cell : result1.listCells()){
String family = Bytes.toString(CellUtil.cloneFamily(cell));
String qualifier = Bytes.toString(CellUtil.cloneQualifier(cell));
String value = Bytes.toString(CellUtil.cloneValue(cell));
System.out.println(family + ":" + qualifier + " " + value);
}
Filter filter2 = new QualifierFilter(CompareOperator.EQUAL,
new SubstringComparator("c")); //列名过滤器
Get get2 = new Get(Bytes.toBytes("2020"));
get2.setFilter(filter2);
Result result2 = table.get(get2);
System.out.println("row:" + new String(result2.getRow(),"utf-8"));
for(Cell cell : result2.listCells()){
String family = Bytes.toString(CellUtil.cloneFamily(cell));
String qualifier = Bytes.toString(CellUtil.cloneQualifier(cell));
String value = Bytes.toString(CellUtil.cloneValue(cell));
System.out.println(family + ":" + qualifier + " " + value);
}
Scan scan3 = new Scan();
Filter filter3 = new ValueFilter(CompareOperator.EQUAL, new SubstringComparator("张")); //值过滤器
scan3.setFilter(filter3);
ResultScanner scanner3 = table.getScanner(scan3);
for (Result result : scanner3) {
System.out.println("row:" + new String(result.getRow(),"utf-8"));
for(Cell cell : result.listCells()){
String family = Bytes.toString(CellUtil.cloneFamily(cell));
String qualifier = Bytes.toString(CellUtil.cloneQualifier(cell));
String value = Bytes.toString(CellUtil.cloneValue(cell));
System.out.println(family + ":" + qualifier + " " + value);
}
}
scanner3.close();
conn.close();
/********* End *********/
}
}
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