Apache HBase 是 Java 语言编写的一款 Apache 开源的 NoSQL 型数据库，不支持 SQL，不支持事务，不支持 Join 操作，没有表关系。Apache HBase 构建在 Apache Hadoop 和 Apache Zookeeper 之上。
Apache HBase: https://hbase.apache.org/
HBase 的安装配置，请参考 “Springboot 系列 (24) - Springboot+HBase 大数据存储（二）| 安装配置 Apache HBase 和 Apache Zookeeper”。
本文将创建一个 SpringBoot 项目，演示通过 HBase API 方式访问 HBase。
1. HBase 运行环境
操作系统：Ubuntu 20.04
Hadoop 版本：3.2.2
Zookeeper 版本：3.6.3
HBase 版本：2.4.4
HBase 所在路径：~/apps/hbase-2.4.4/
本文 HBase 在 HBase + Zookeeper (独立的) 模式下运行，Zookeeper 使用端口 2182。
2. 创建 Springboot 项目
Windows版本：Windows 10 Home (20H2)
IntelliJ IDEA：Community Edition for Windows 2020.1.4
Apache Maven：3.8.1
注：Spring 开发环境的搭建，可以参考 “ Spring基础知识（1）- Spring简介、Spring体系结构和开发环境配置 ”。
1) 运行 IDEA 创建项目
点击菜单 New 创建 Project：
New Project -> Project Type: Maven -> Project SDK: 1.8 -> Check "Create from archtype" -> select "org.apache.maven.archtypes:maven-archtype-quickstart" -> Next
Name: SpringbootExample21
GroupId: com.example
ArtifactId: SpringbootExample21
-> Finish
2) 修改 pom.xml
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.example</groupId> <artifactId>SpringbootExample21</artifactId> <version>1.0-SNAPSHOT</version> <name>SpringbootExample21</name> <!-- FIXME change it to the project's website --> <url>http://www.example.com</url> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <maven.compiler.source>1.8</maven.compiler.source> <maven.compiler.target>1.8</maven.compiler.target> </properties> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.6.6</version> <relativePath/> <!-- lookup parent from repository --> </parent> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.11</version> <scope>test</scope> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> <configuration> <mainClass>com.example.App</mainClass> <layout>JAR</layout> </configuration> <executions> <execution> <goals> <goal>repackage</goal> </goals> </execution> </executions> </plugin> </plugins> <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) --> <plugins> ... </plugins> </pluginManagement> </build> </project>
在IDE中项目列表 -> SpringbootExample21 -> 点击鼠标右键 -> Maven -> Reload Project
本文选择了 spring-boot-starter-parent 2.6.6 相关依赖包，spring-boot-starter 和 spring-boot-starter-test 的版本由 spring-boot-starter-parent 控制。
3) 修改 src/main/java/com/example/App.java 文件
package com.example; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplication public class App { public static void main(String[] args) { SpringApplication.run(App.class, args); System.out.println("Spring boot jar empty project"); } }
4) 添加 src/main/resources/application.properties 文件
spring.main.banner-mode=off
# database - hbase
hbase.zookeeper.quorum=localhost
hbase.zookeeper.property.clientPort=2182
zookeeper.znode.parent=/hbase
5) 运行
Run -> Edit configurations -> Click "+" -> Select "Maven"
Command line: clean spring-boot:run
Name: SpringbootExample21 [clean,spring-boot:run]
-> OK
Run -> Run "SpringbootExample21 [clean,spring-boot:run]"
Spring boot jar empty project
3. 添加 hbase-client 依赖
1) 修改 pom.xml
<project ... > ... <dependencies> ... <dependency> <groupId>org.apache.hbase</groupId> <artifactId>hbase-client</artifactId> <version>2.4.4</version> <exclusions> <exclusion> <groupId>org.slf4j</groupId> <artifactId>slf4j-log4j12</artifactId> </exclusion> </exclusions> </dependency> </dependencies> </project>
在IDE中项目列表 -> SpringbootExample21 -> 点击鼠标右键 -> Maven -> Reload Project
2) 修改 src/main/resources/application.properties 文件
spring.main.banner-mode=off
hbase.zookeeper.quorum=localhost
hbase.zookeeper.property.clientPort=2182
zookeeper.znode.parent=/hbase
4. HBase API 示例
HBase API: https://hbase.apache.org/book.html#hbase_apis
API Reference : https://hbase.apache.org/apidocs/index.html
1) 修改 src/main/java/com/example/App.java 文件
package com.example; import java.io.IOException; import java.util.ArrayList; import java.util.List; import org.apache.commons.lang.StringUtils; import org.apache.hadoop.hbase.TableName; import org.apache.hadoop.hbase.Cell; import org.apache.hadoop.hbase.CompareOperator; import org.apache.hadoop.hbase.client.*; import org.apache.hadoop.hbase.filter.RowFilter; import org.apache.hadoop.hbase.filter.SubstringComparator; import org.apache.hadoop.hbase.util.Bytes; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplication public class App { private static Connection hbaseConnection; private static Admin hbaseAdmin; public static void main(String[] args) { SpringApplication.run(App.class, args); // try { org.apache.hadoop.conf.Configuration hbaseConf = new org.apache.hadoop.conf.Configuration(); hbaseConf.set("hbase.zookeeper.quorum", "localhost"); hbaseConf.set("hbase.zookeeper.property.clientPort", "2182"); //hbaseConf.setInt("hbase.hconnection.threads.max", 100); //hbaseConf.setInt("hbase.hconnection.threads.core", 50); //hbaseConf.setLong("hbase.hconnection.threads.keepalivetime", 1000); hbaseConf.set("zookeeper.znode.parent", "/hbase"); hbaseConnection = ConnectionFactory.createConnection(hbaseConf); hbaseAdmin = hbaseConnection.getAdmin(); System.out.println("App -> getAdmin(): hbaseAdmin = " + hbaseAdmin); if (App.tableExists("user")) { System.out.println("App -> tableExists('user') = true"); } // Delete table if exists System.out.println("App -> tableExists('user')"); if (App.tableExists("user")) { System.out.println("App -> deleteTable('user')"); App.deleteTable("user"); } // Create table System.out.println("App -> createTable('user', ...)"); App.createTable("user", new String[]{"cf1", "cf2", "cf3"}); // Insert data System.out.println("App -> insertRecords('user', ... )"); App.insertRecords("user", "row1", "cf1", new String[]{"name", "age"}, new String[] {"Tom", "12"}); App.insertRecords("user", "row2", "cf1", new String[]{"name", "age"}, new String[] {"Jerry", "9"}); App.insertRecord("user", "row1", "cf2", "job", "Student"); App.insertRecord("user", "row1", "cf3", "gender", "Male"); App.insertRecord("user", "row2", "cf2", "job", "Student2"); App.insertRecord("user", "row2", "cf3", "gender", "Female"); // Scan table System.out.println("App -> scanTable('user')"); System.out.println(App.scanTable("user")); // Get value String value = App.getValue("user", "row1", "cf3", "gender"); System.out.println("App -> getValue('user', 'row1', 'cf3', 'gender'): value = " + value); // Delete column System.out.println("App -> deleteColumn('user', 'row1', 'cf3', 'gender')"); App.deleteColumn("user", "row1", "cf3", "gender"); // Get row System.out.println("App -> getRow('user', 'row1')"); System.out.println(App.getRow("user", "row1")); // Delete column family System.out.println("App -> deleteColumnFamily('user', 'row1', 'cf2')"); App.deleteColumnFamily("user", "row1", "cf2"); // Scan table row System.out.println("App -> scanRow('user', 'row1')"); System.out.println(App.scanRow("user", "row1")); // Delete row System.out.println("App -> deleteRow('user', 'row1')"); App.deleteRow("user", "row1"); // Scan table (2) System.out.println("App -> scanTable('user')"); System.out.println(App.scanTable("user")); hbaseAdmin.close(); hbaseConnection.close(); } catch (IOException e) { } } public static boolean tableExists(String tableName) throws IOException { TableName[] tableNames = hbaseAdmin.listTableNames(); if (tableNames != null && tableNames.length > 0) { for (int i = 0; i < tableNames.length; i++) { if (tableName.equals(tableNames[i].getNameAsString())) { return true; } } } return false; } public static void createTable(String tableName, String[] columnFamilies) throws IOException { TableName name = TableName.valueOf(tableName); TableDescriptorBuilder descriptorBuilder = TableDescriptorBuilder.newBuilder(name); List<ColumnFamilyDescriptor> columnFamilyList = new ArrayList<>(); for (String columnFamily : columnFamilies) { ColumnFamilyDescriptor columnFamilyDescriptor = ColumnFamilyDescriptorBuilder.newBuilder(columnFamily.getBytes()).build(); columnFamilyList.add(columnFamilyDescriptor); } descriptorBuilder.setColumnFamilies(columnFamilyList); TableDescriptor tableDescriptor = descriptorBuilder.build(); hbaseAdmin.createTable(tableDescriptor); } public static void deleteTable(String tableName) throws IOException { boolean isExists = App.tableExists(tableName); if (!isExists) { return; } TableName name = TableName.valueOf(tableName); hbaseAdmin.disableTable(name); hbaseAdmin.deleteTable(name); } public static void insertRecord(String tableName, String row, String columnFamily, String column, String value) throws IOException { TableName name = TableName.valueOf(tableName); Table table = hbaseConnection.getTable(name); Put put = new Put(Bytes.toBytes(row)); put.addColumn(Bytes.toBytes(columnFamily), Bytes.toBytes(column), Bytes.toBytes(value)); table.put(put); table.close(); } public static void insertRecords(String tableName, String row, String columnFamily, String[] columns, String[] values) throws IOException { TableName name = TableName.valueOf(tableName); Table table = hbaseConnection.getTable(name); Put put = new Put(Bytes.toBytes(row)); for (int i = 0; i < columns.length; i++) { put.addColumn(Bytes.toBytes(columnFamily), Bytes.toBytes(columns[i]), Bytes.toBytes(values[i])); table.put(put); } table.close(); } public static String getRow(String tableName, String rowKey) throws IOException { Table table = hbaseConnection.getTable(TableName.valueOf(tableName)); Get g = new Get(rowKey.getBytes()); Result rs = table.get(g); String str = ""; for (Cell cell : rs.rawCells()) { StringBuffer stringBuffer = new StringBuffer() .append(Bytes.toString(cell.getRowArray(), cell.getRowOffset(), cell.getRowLength())).append("\t") .append(Bytes.toString(cell.getFamilyArray(), cell.getFamilyOffset(), cell.getFamilyLength())).append("\t") .append(Bytes.toString(cell.getQualifierArray(), cell.getQualifierOffset(), cell.getQualifierLength())).append("\t") .append(Bytes.toString(cell.getValueArray(), cell.getValueOffset(), cell.getValueLength())).append("\n"); str += stringBuffer.toString(); } table.close(); return str; } public static String getValue(String tableName, String rowKey, String family, String column) throws IOException { Table table = hbaseConnection.getTable(TableName.valueOf(tableName)); String value = ""; if (StringUtils.isBlank(tableName) || StringUtils.isBlank(family) || StringUtils.isBlank(rowKey) || StringUtils.isBlank(column)) { return null; } Get g = new Get(rowKey.getBytes()); g.addColumn(family.getBytes(), column.getBytes()); Result result = table.get(g); List<Cell> ceList = result.listCells(); if (ceList != null && ceList.size() > 0) { for (Cell cell : ceList) { value = Bytes.toString(cell.getValueArray(), cell.getValueOffset(), cell.getValueLength()); } } table.close(); return value; } public static String scanTable(String tableName) throws IOException { Table table = hbaseConnection.getTable(TableName.valueOf(tableName)); Scan scan = new Scan(); ResultScanner scanner = table.getScanner(scan); String str = ""; for (Result result : scanner){ for (Cell cell : result.rawCells()) { StringBuffer stringBuffer = new StringBuffer() .append(Bytes.toString(cell.getRowArray(), cell.getRowOffset(), cell.getRowLength())).append("\t") .append(Bytes.toString(cell.getFamilyArray(), cell.getFamilyOffset(), cell.getFamilyLength())).append("\t") .append(Bytes.toString(cell.getQualifierArray(), cell.getQualifierOffset(), cell.getQualifierLength())).append("\t") .append(Bytes.toString(cell.getValueArray(), cell.getValueOffset(), cell.getValueLength())).append("\n"); str += stringBuffer.toString(); } } scanner.close(); table.close(); return str; } public static String scanRow(String tableName, String rowKeyword) throws IOException { ArrayList<Object> list = new ArrayList<Object>(); Table table = hbaseConnection.getTable(TableName.valueOf(tableName)); Scan scan = new Scan(); RowFilter rowFilter = new RowFilter(CompareOperator.EQUAL, new SubstringComparator(rowKeyword)); scan.setFilter(rowFilter); ResultScanner scanner = table.getScanner(scan); String str = ""; for (Result result : scanner) { for (Cell cell : result.rawCells()) { StringBuffer stringBuffer = new StringBuffer() .append(Bytes.toString(cell.getRowArray(), cell.getRowOffset(), cell.getRowLength())).append("\t") .append(Bytes.toString(cell.getFamilyArray(), cell.getFamilyOffset(), cell.getFamilyLength())).append("\t") .append(Bytes.toString(cell.getQualifierArray(), cell.getQualifierOffset(), cell.getQualifierLength())).append("\t") .append(Bytes.toString(cell.getValueArray(), cell.getValueOffset(), cell.getValueLength())).append("\n"); str += stringBuffer.toString(); } } scanner.close(); table.close(); return str; } public static void deleteRow(String tableName, String rowKey) throws IOException { Table table = hbaseConnection.getTable(TableName.valueOf(tableName)); Delete delete = new Delete(rowKey.getBytes()); table.delete(delete); table.close(); } public static void deleteColumnFamily(String tableName, String rowKey, String columnFamily) throws IOException { Table table = hbaseConnection.getTable(TableName.valueOf(tableName)); Delete delete = new Delete(rowKey.getBytes()); delete.addFamily(Bytes.toBytes(columnFamily)); table.delete(delete); table.close(); } public static void deleteColumn(String tableName, String rowKey, String columnFamily, String column) throws IOException { Table table = hbaseConnection.getTable(TableName.valueOf(tableName)); Delete delete = new Delete(rowKey.getBytes()); delete.addColumn(Bytes.toBytes(columnFamily), Bytes.toBytes(column)); table.delete(delete); table.close(); } }
2) 打包 jar
菜单 View -> Tool Windows -> Maven -> SpringbootExample21 -> Lifecycle -> Clean & Package
jar 包生成在目录 target/ 里
SpringbootExample21-1.0-SNAPSHOT.jar
SpringbootExample21-1.0-SNAPSHOT.jar.original
SpringbootExample21.jar 包含依赖包，可以直接运行。 SpringbootExample21.jar.original 里不包含依赖的包（要手动配置依赖环境），运行前要把文件名上的 “.original” 去掉。
3) 运行 jar
本文 HBase 2.4.4 在 Ubuntu 20.04 主机的 ~/apps 目录。
把 SpringbootExample21-1.0-SNAPSHOT.jar 文件复制到 ~/apps 目录下，运行如下命令：
$ java -jar SpringbootExample21-1.0-SNAPSHOT.jar
2023-03-30 12:05:59.993 INFO 7989 --- [ main] com.example.App : Starting App v1.0-SNAPSHOT using Java 11.0.18 on Test-Ubuntu20 with PID 7989 (/home/xxx/apps/SpringbootExample21-1.0-SNAPSHOT.jar started by xxx in /home/xxx/apps)
2023-03-30 12:05:59.998 INFO 7989 --- [ main] com.example.App : No active profile set, falling back to 1 default profile: "default"
2023-03-30 12:06:00.490 INFO 7989 --- [ main] com.example.App : Started App in 0.882 seconds (JVM running for 1.214)
2023-03-30 12:06:00.584 WARN 7989 --- [ main] org.apache.hadoop.util.NativeCodeLoader : Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by org.apache.hadoop.security.authentication.util.KerberosUtil (jar:file:/home/xxx/apps/SpringbootExample21-1.0-SNAPSHOT.jar!/BOOT-INF/lib/hadoop-auth-2.10.0.jar!/) to method sun.security.krb5.Config.getInstance()
WARNING: Please consider reporting this to the maintainers of org.apache.hadoop.security.authentication.util.KerberosUtil
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
2023-03-30 12:06:00.787 INFO 7989 --- [2182@0x55cb6996] org.apache.zookeeper.ZooKeeper : Client environment:zookeeper.version=3.5.7-f0fdd52973d373ffd9c86b81d99842dc2c7f660e, built on 02/10/2020 11:30 GMT
2023-03-30 12:06:00.788 INFO 7989 --- [2182@0x55cb6996] org.apache.zookeeper.ZooKeeper : Client environment:host.name=Tom-Ubuntu20
2023-03-30 12:06:00.788 INFO 7989 --- [2182@0x55cb6996] org.apache.zookeeper.ZooKeeper : Client environment:java.version=11.0.18
2023-03-30 12:06:00.788 INFO 7989 --- [2182@0x55cb6996] org.apache.zookeeper.ZooKeeper : Client environment:java.vendor=Ubuntu
2023-03-30 12:06:00.788 INFO 7989 --- [2182@0x55cb6996] org.apache.zookeeper.ZooKeeper : Client environment:java.home=/usr/lib/jvm/java-11-openjdk-amd64
2023-03-30 12:06:00.788 INFO 7989 --- [2182@0x55cb6996] org.apache.zookeeper.ZooKeeper : Client environment:java.class.path=SpringbootExample21-1.0-SNAPSHOT.jar
2023-03-30 12:06:00.788 INFO 7989 --- [2182@0x55cb6996] org.apache.zookeeper.ZooKeeper : Client environment:java.library.path=/usr/java/packages/lib:/usr/lib/x86_64-linux-gnu/jni:/lib/x86_64-linux-gnu:/usr/lib/x86_64-linux-gnu:/usr/lib/jni:/lib:/usr/lib
2023-03-30 12:06:00.788 INFO 7989 --- [2182@0x55cb6996] org.apache.zookeeper.ZooKeeper : Client environment:java.io.tmpdir=/tmp
2023-03-30 12:06:00.788 INFO 7989 --- [2182@0x55cb6996] org.apache.zookeeper.ZooKeeper : Client environment:java.compiler=<NA>
2023-03-30 12:06:00.788 INFO 7989 --- [2182@0x55cb6996] org.apache.zookeeper.ZooKeeper : Client environment:os.name=Linux
2023-03-30 12:06:00.788 INFO 7989 --- [2182@0x55cb6996] org.apache.zookeeper.ZooKeeper : Client environment:os.arch=amd64
2023-03-30 12:06:00.788 INFO 7989 --- [2182@0x55cb6996] org.apache.zookeeper.ZooKeeper : Client environment:os.version=5.15.0-69-generic
2023-03-30 12:06:00.788 INFO 7989 --- [2182@0x55cb6996] org.apache.zookeeper.ZooKeeper : Client environment:user.name=xxx
2023-03-30 12:06:00.788 INFO 7989 --- [2182@0x55cb6996] org.apache.zookeeper.ZooKeeper : Client environment:user.home=/home/xxx
2023-03-30 12:06:00.788 INFO 7989 --- [2182@0x55cb6996] org.apache.zookeeper.ZooKeeper : Client environment:user.dir=/home/xxx/apps
2023-03-30 12:06:00.789 INFO 7989 --- [2182@0x55cb6996] org.apache.zookeeper.ZooKeeper : Client environment:os.memory.free=37MB
2023-03-30 12:06:00.789 INFO 7989 --- [2182@0x55cb6996] org.apache.zookeeper.ZooKeeper : Client environment:os.memory.max=494MB
2023-03-30 12:06:00.789 INFO 7989 --- [2182@0x55cb6996] org.apache.zookeeper.ZooKeeper : Client environment:os.memory.total=57MB
2023-03-30 12:06:00.792 INFO 7989 --- [2182@0x55cb6996] org.apache.zookeeper.ZooKeeper : Initiating client connection, connectString=192.168.1.4:2182 sessionTimeout=90000 watcher=org.apache.hadoop.hbase.zookeeper.ReadOnlyZKClient$$Lambda$398/0x0000000840296440@40e9164d
2023-03-30 12:06:00.798 INFO 7989 --- [2182@0x55cb6996] org.apache.zookeeper.common.X509Util : Setting -D jdk.tls.rejectClientInitiatedRenegotiation=true to disable client-initiated TLS renegotiation
2023-03-30 12:06:00.806 INFO 7989 --- [2182@0x55cb6996] org.apache.zookeeper.ClientCnxnSocket : jute.maxbuffer value is 4194304 Bytes
2023-03-30 12:06:00.819 INFO 7989 --- [2182@0x55cb6996] org.apache.zookeeper.ClientCnxn : zookeeper.request.timeout value is 0. feature enabled=
2023-03-30 12:06:00.853 INFO 7989 --- [2.168.1.4:2182)] org.apache.zookeeper.ClientCnxn : Opening socket connection to server 192.168.1.4/192.168.1.4:2182. Will not attempt to authenticate using SASL (unknown error)
2023-03-30 12:06:00.862 INFO 7989 --- [2.168.1.4:2182)] org.apache.zookeeper.ClientCnxn : Socket connection established, initiating session, client: /192.168.1.4:43262, server: 192.168.1.4/192.168.1.4:2182
2023-03-30 12:06:00.873 INFO 7989 --- [2.168.1.4:2182)] org.apache.zookeeper.ClientCnxn : Session establishment complete on server 192.168.1.4/192.168.1.4:2182, sessionid = 0x10000053fd6000c, negotiated timeout = 40000
App -> getAdmin(): hbaseAdmin = org.apache.hadoop.hbase.client.HBaseAdmin@3e2055d6
App -> tableExists('user') = true
App -> tableExists('user')
App -> deleteTable('user')
2023-03-30 12:06:01.343 INFO 7989 --- [ main] o.apache.hadoop.hbase.client.HBaseAdmin : Started disable of user
2023-03-30 12:06:01.736 INFO 7989 --- [ main] o.apache.hadoop.hbase.client.HBaseAdmin : Operation: DISABLE, Table Name: default:user, procId: 1135 completed
2023-03-30 12:06:02.077 INFO 7989 --- [ main] o.apache.hadoop.hbase.client.HBaseAdmin : Operation: DELETE, Table Name: default:user, procId: 1138 completed
App -> createTable('user', ...)
2023-03-30 12:06:02.812 INFO 7989 --- [ main] o.apache.hadoop.hbase.client.HBaseAdmin : Operation: CREATE, Table Name: default:user, procId: 1139 completed
App -> insertRecords('user', ... )
App -> scanTable('user')
row1 cf1 age 12
row1 cf1 name Tom
row1 cf2 job Student
row1 cf3 gender Male
row2 cf1 age 9
row2 cf1 name Jerry
row2 cf2 job Student2
row2 cf3 gender Female
App -> getValue('user', 'row1', 'cf3', 'gender'): value = Male
App -> deleteColumn('user', 'row1', 'cf3', 'gender')
App -> getRow('user', 'row1')
row1 cf1 age 12
row1 cf1 name Tom
row1 cf2 job Student
App -> deleteColumnFamily('user', 'row1', 'cf2')
App -> scanRow('user', 'row1')
row1 cf1 age 12
row1 cf1 name Tom
App -> deleteRow('user', 'row1')
App -> scanTable('user')
row2 cf1 age 9
row2 cf1 name Jerry
row2 cf2 job Student2
row2 cf3 gender Female
2023-03-30 12:06:03.063 INFO 7989 --- [ main] o.a.h.h.client.ConnectionImplementation : Closing master protocol: MasterService