熟悉常用的HBase操作01
（一）编程实现以下指定功能，并用Hadoop提供的HBase Shell命令完成相同任务：
（1） 列出HBase所有的表的相关信息，例如表名；
（2） 在终端打印出指定的表的所有记录数据；
（3） 向已经创建好的表添加和删除指定的列族或列；
（4） 清空指定的表的所有记录数据；
（5） 统计表的行数。
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代码：
package hbase;
import hbase.HBaseConfig;
import org.apache.hadoop.hbase.client.*;
import org.apache.hadoop.hbase.*;
import org.apache.hadoop.hbase.util.Bytes;
import java.io.IOException;
public class HBaseOperations {
private static Connection connection;
private static Admin admin;
static {
try {
connection = ConnectionFactory.createConnection(HBaseConfig.getConfig());
admin = connection.getAdmin();
} catch (IOException e) {
e.printStackTrace();
}
}
// (1) 列出所有表信息
public static void listTables() throws IOException {
HTableDescriptor[] tableDescriptors = admin.listTables();
System.out.println("HBase 表列表:");
for (HTableDescriptor table : tableDescriptors) {
System.out.println(" - " + table.getTableName());
}
}
// (2) 打印指定表的所有记录
public static void printTable(String tableName) throws IOException {
Table table = connection.getTable(TableName.valueOf(tableName));
Scan scan = new Scan();
ResultScanner scanner = table.getScanner(scan);
for (Result result : scanner) {
System.out.println("行: " + Bytes.toString(result.getRow()));
for (Cell cell : result.rawCells()) {
System.out.println(" - 列: " + Bytes.toString(CellUtil.cloneFamily(cell)) + ":" +
Bytes.toString(CellUtil.cloneQualifier(cell)) +
", 值: " + Bytes.toString(CellUtil.cloneValue(cell)));
}
}
table.close();
}
// (3) 添加和删除列族
public static void modifyColumnFamily(String tableName, String columnFamily, boolean add) throws IOException {
TableName table = TableName.valueOf(tableName);
if (!admin.tableExists(table)) {
System.out.println("表不存在.");
return;
}
if (add) {
HColumnDescriptor columnDescriptor = new HColumnDescriptor(columnFamily);
admin.addColumn(table, columnDescriptor);
System.out.println("已添加列族: " + columnFamily);
} else {
admin.deleteColumn(table, Bytes.toBytes(columnFamily));
System.out.println("已删除列族: " + columnFamily);
}
}
// (4) 清空表中的所有记录
public static void truncateTable(String tableName) throws IOException {
TableName table = TableName.valueOf(tableName);
if (admin.tableExists(table)) {
admin.disableTable(table);
admin.truncateTable(table, true);
System.out.println("表 " + tableName + " 已清空.");
} else {
System.out.println("表不存在.");
}
}
// (5) 统计表的行数
public static void countRows(String tableName) throws IOException {
Table table = connection.getTable(TableName.valueOf(tableName));
Scan scan = new Scan();
ResultScanner scanner = table.getScanner(scan);
int rowCount = 0;
for (Result ignored : scanner) {
rowCount++;
}
System.out.println("表 " + tableName + " 总行数: " + rowCount);
table.close();
}
// 关闭连接
public static void closeConnection() {
try {
if (admin != null) admin.close();
if (connection != null) connection.close();
} catch (IOException e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
try {
// 测试功能
String tableName = "Student";
listTables();
printTable(tableName);
modifyColumnFamily(tableName, "列族", true);
modifyColumnFamily(tableName, "列族2", true);
modifyColumnFamily(tableName, "列族", false);
truncateTable(tableName);
countRows(tableName);
} catch (IOException e) {
e.printStackTrace();
} finally {
closeConnection();
}
}
}
（二）HBase数据库操作
1. 现有以下关系型数据库中的表和数据（见表14-3到表14-5），要求将其转换为适合于HBase存储的表并插入数据：
表14-3 学生表（Student）
|
学号（S_No） |
姓名（S_Name） |
性别（S_Sex） |
年龄（S_Age） |
|
2015001 |
Zhangsan |
male |
23 |
|
2015002 |
Mary |
female |
22 |
|
2015003 |
Lisi |
male |
24 |
表14-4 课程表（Course）
|
课程号（C_No） |
课程名（C_Name） |
学分（C_Credit） |
|
123001 |
Math |
2.0 |
|
123002 |
Computer Science |
5.0 |
|
123003 |
English |
3.0 |
表14-5 选课表（SC）
|
学号（SC_Sno） |
课程号（SC_Cno） |
成绩（SC_Score） |
|
2015001 |
123001 |
86 |
|
2015001 |
123003 |
69 |
|
2015002 |
123002 |
77 |
|
2015002 |
123003 |
99 |
|
2015003 |
123001 |
98 |
|
2015003 |
123002 |
95 |
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运行截图：
代码：
package hbase;
import org.apache.hadoop.hbase.client.*;
import org.apache.hadoop.hbase.*;
import org.apache.hadoop.hbase.util.Bytes;
import java.io.IOException;
public class HBaseOperations1 {
private static Connection connection;
private static Admin admin;
static {
try {
connection = ConnectionFactory.createConnection(HBaseConfig.getConfig());
admin = connection.getAdmin();
} catch (IOException e) {
e.printStackTrace();
}
}
// 创建表
public static void createTable(String tableName, String[] columnFamilies) throws IOException {
TableName table = TableName.valueOf(tableName);
if (admin.tableExists(table)) {
System.out.println("表 " + tableName + " 已经存在，正在删除...");
admin.disableTable(table);
admin.deleteTable(table);
}
HTableDescriptor tableDescriptor = new HTableDescriptor(table);
for (String cf : columnFamilies) {
tableDescriptor.addFamily(new HColumnDescriptor(cf));
}
admin.createTable(tableDescriptor);
System.out.println("表 " + tableName + " 创建成功。");
}
// 插入数据
public static void addRecord(String tableName, String rowKey, String columnFamily, String column, String value) throws IOException {
Table table = connection.getTable(TableName.valueOf(tableName));
Put put = new Put(Bytes.toBytes(rowKey));
put.addColumn(Bytes.toBytes(columnFamily), Bytes.toBytes(column), Bytes.toBytes(value));
table.put(put);
table.close();
System.out.println("已插入记录到表 " + tableName + ": 行键=" + rowKey + ", " + columnFamily + ":" + column + "=" + value);
}
// 关闭连接
public static void closeConnection() {
try {
if (admin != null) admin.close();
if (connection != null) connection.close();
} catch (IOException e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
try {
// 1. 创建学生表
String studentTable = "Student";
String[] studentCF = {"info"};
createTable(studentTable, studentCF);
// 插入学生表数据
addRecord(studentTable, "2015001", "info", "name", "Zhangsan");
addRecord(studentTable, "2015001", "info", "sex", "male");
addRecord(studentTable, "2015001", "info", "age", "23");
addRecord(studentTable, "2015002", "info", "name", "Mary");
addRecord(studentTable, "2015002", "info", "sex", "female");
addRecord(studentTable, "2015002", "info", "age", "22");
addRecord(studentTable, "2015003", "info", "name", "Lisi");
addRecord(studentTable, "2015003", "info", "sex", "male");
addRecord(studentTable, "2015003", "info", "age", "24");
// 2. 创建课程表
String courseTable = "Course";
String[] courseCF = {"details"};
createTable(courseTable, courseCF);
// 插入课程表数据
addRecord(courseTable, "123001", "details", "name", "Math");
addRecord(courseTable, "123001", "details", "credit", "2.0");
addRecord(courseTable, "123002", "details", "name", "Computer Science");
addRecord(courseTable, "123002", "details", "credit", "5.0");
addRecord(courseTable, "123003", "details", "name", "English");
addRecord(courseTable, "123003", "details", "credit", "3.0");
// 3. 创建选课表
String scTable = "SC";
String[] scCF = {"score"};
createTable(scTable, scCF);
// 插入选课表数据
addRecord(scTable, "2015001:123001", "score", "score", "86");
addRecord(scTable, "2015001:123003", "score", "score", "69");
addRecord(scTable, "2015002:123002", "score", "score", "77");
addRecord(scTable, "2015002:123003", "score", "score", "99");
addRecord(scTable, "2015003:123001", "score", "score", "98");
addRecord(scTable, "2015003:123002", "score", "score", "95");
} catch (IOException e) {
e.printStackTrace();
} finally {
closeConnection();
}
}
}
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