HBase学习笔记（2）—— API使用
对HBase中常用的API操作进行简单的介绍
对应HBase学习笔记（1）—— 知识点总结-CSDN博客中介绍的HBase Shell常用操作
更多用法请参考官网：Apache HBase ™ Reference Guide
依赖导入
org.apache.hbase
hbase-server
2.4.11
org.glassfish
javax.el
org.glassfish
javax.el
3.0.1-b06
打包所用的插件：
org.apache.maven.plugins
maven-shade-plugin
3.2.4
package
shade
建立连接
package com.why;
import org.apache.hadoop.hbase.client.Connection;
import org.apache.hadoop.hbase.client.ConnectionFactory;
import java.io.IOException;
public class HBaseConnect2 {
public static Connection connection = null;
static {
try {
connection = ConnectionFactory.createConnection(); //使用配置文件中的参数hbase.zookeeper.quorum
System.out.println(connection);
} catch (IOException e) {
System.out.println("连接创建失败");
throw new RuntimeException(e);
}
}
/**
* 关闭连接
* @throws IOException
*/
public static void closeConnection() throws IOException {
if (connection != null)
{
connection.close();
}
}
}
DDL操作
package com.why;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.NamespaceDescriptor;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.*;
import org.apache.hadoop.hbase.util.Bytes;
import java.io.IOException;
public class HBaseDDL {
//获取连接
private static Connection connection = HBaseConnect2.connection;
/**
* 创建命名空间
* @param namespace 命名空间名称
* @throws IOException
*/
public static void createNamespace(String namespace) throws IOException {
//获取admin(admin的连接是轻量级的，不是线程安全的，不推荐池化或缓存)
Admin admin = connection.getAdmin();
//创建命名空间builder
NamespaceDescriptor.Builder builder = NamespaceDescriptor.create(namespace);
// builder.addConfiguration("user","why");
try{
admin.createNamespace(builder.build());
}catch (IOException e)
{
System.out.println("命名空间已经存在");
e.printStackTrace();
}
admin.close();
}
/**
* 查看所有命名空间
* @throws IOException
*/
public static void listNamespaces() throws IOException {
Admin admin = connection.getAdmin();
try {
String[] strings = admin.listNamespaces();
System.out.println("命名空间如下:");
for(String string : strings)
{
System.out.println(string);
}
}catch (IOException e)
{
e.printStackTrace();
}
admin.close();
}
/**
* 判断表格是否存在
* @param namespace 命名空间
* @param table 表格名称
* @return
* @throws IOException
*/
public static boolean isTableExist(String namespace,String table) throws IOException {
Admin admin = connection.getAdmin();
boolean isExist = false;
try {
//通过tableExists方法判断表格是否存在
isExist = admin.tableExists(TableName.valueOf(namespace,table));
}catch (IOException e)
{
e.printStackTrace();
}
admin.close();
return isExist;
}
/**
* 创建表格
* @param namespace 命名空间
* @param table 表格名称
* @param columnFamilies 列族名称
* @throws IOException
*/
public static void createTable(String namespace , String table , String... columnFamilies) throws IOException {
//判断是否至少有一个列族
if(columnFamilies.length == 0)
{
System.out.println("至少要有一个列族");
return;
}
//判断表格是否已经存在
if(isTableExist(namespace,table))
{
System.out.println("表格已经存在");
return;
}
Admin admin = connection.getAdmin();
//创建表格描述的构建器
TableDescriptorBuilder tableDescriptorBuilder = TableDescriptorBuilder.newBuilder(TableName.valueOf(namespace, table));
//添加参数
for(String columnFamily : columnFamilies)
{
//创建列族描述的构建器
ColumnFamilyDescriptorBuilder columnFamilyDescriptorBuilder = ColumnFamilyDescriptorBuilder.newBuilder(Bytes.toBytes(columnFamily));
columnFamilyDescriptorBuilder.setMaxVersions(5); //添加最大版本数
tableDescriptorBuilder.setColumnFamily(columnFamilyDescriptorBuilder.build()); //创建添加完参数的列族描述
}
try {
admin.createTable(tableDescriptorBuilder.build());
}catch (IOException e)
{
e.printStackTrace();
}
admin.close();
}
/**
* 查看所有表格
* @throws IOException
*/
public static void listTableNames() throws IOException {
Admin admin = connection.getAdmin();
try {
TableName[] tableNames = admin.listTableNames();
System.out.println("所有表格如下");
for(TableName tableName : tableNames)
{
System.out.println(tableName.getNamespaceAsString() + ":" + tableName.getNameAsString());
}
}catch (IOException e)
{
e.printStackTrace();
}
admin.close();
}
/**
* 修改表格中某一个列族的版本号
* @param namespace
* @param table
* @param columnFamily 列族
* @param version 版本号
*/
public static void modifyTable(String namespace , String table , String columnFamily , int version) throws IOException {
if(!isTableExist(namespace,table))
{
System.out.println("表格不存在，无法修改");
return;
}
Admin admin = connection.getAdmin();
try {
//获取表格描述
TableDescriptor descriptor = admin.getDescriptor(TableName.valueOf(namespace, table));
//创建新的表格描述构建器
TableDescriptorBuilder tableDescriptorBuilder = TableDescriptorBuilder.newBuilder(descriptor);
//获取列族描述
ColumnFamilyDescriptor columnFamily1 = descriptor.getColumnFamily(Bytes.toBytes(columnFamily));
//创建新的列族描述构建器
ColumnFamilyDescriptorBuilder columnFamilyDescriptorBuilder = ColumnFamilyDescriptorBuilder.newBuilder(columnFamily1);
//设置参数
columnFamilyDescriptorBuilder.setMaxVersions(version);
//将新的列族描述添加到表格描述中
tableDescriptorBuilder.modifyColumnFamily(columnFamilyDescriptorBuilder.build());
admin.modifyTable(tableDescriptorBuilder.build());
}catch (IOException e)
{
e.printStackTrace();
}
admin.close();
}
/**
*
* @param namespace
* @param table
* @return true表示删除成功
*/
public static boolean deleteTable(String namespace , String table) throws IOException {
if(!isTableExist(namespace,table))
{
System.out.println("表格不存在，无法删除");
return false;
}
Admin admin = connection.getAdmin();
try {
TableName tableName = TableName.valueOf(namespace, table);
admin.disableTable(tableName);
admin.deleteTable(tableName);
}catch (IOException e)
{
e.printStackTrace();
}
admin.close();
return true;
}
}
DML操作
package com.why;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.CellUtil;
import org.apache.hadoop.hbase.CompareOperator;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.*;
import org.apache.hadoop.hbase.filter.ColumnValueFilter;
import org.apache.hadoop.hbase.filter.FilterList;
import org.apache.hadoop.hbase.filter.SingleColumnValueFilter;
import org.apache.hadoop.hbase.util.Bytes;
import java.io.IOException;
public class HBaseDML {
private static Connection connection = HBaseConnect2.connection;
/**
* 插入数据
*
* @param namespace
* @param table
* @param rowKey
* @param columnFamily
* @param column
* @param value
* @throws IOException
*/
public static void insert(String namespace, String table, String rowKey, String columnFamily, String column, String value) throws IOException {
//首先获取表格table
Table table1 = connection.getTable(TableName.valueOf(namespace, table));
System.out.println("表格创建成功");
//创建put对象
Put put = new Put(Bytes.toBytes(rowKey));
System.out.println("put对象创建成功");
//向put对象中添加数据
put.addColumn(Bytes.toBytes(columnFamily), Bytes.toBytes(column), Bytes.toBytes(value));
try {
table1.put(put);
System.out.println("数据插入成功");
} catch (IOException e) {
e.printStackTrace();
}
table1.close();
}
/**
* 读取数据
*
* @param namespace
* @param table
* @param rowKey
* @param columnFamily
* @param column
* @throws IOException
*/
public static void get(String namespace, String table, String rowKey, String columnFamily, String column) throws IOException {
//获取table
Table table1 = connection.getTable(TableName.valueOf(namespace, table));
//获取get对象
Get get = new Get(Bytes.toBytes(rowKey));
//设置读取某一列的数据(如果不设置的话则读取所有数据)
get.addColumn(Bytes.toBytes(columnFamily), Bytes.toBytes(column));
try {
//调用get方法读取数据
Result result = table1.get(get);
//获取到所有的cell
Cell[] cells = result.rawCells();
//打印value
for (Cell cell : cells) {
String value = new String(CellUtil.cloneValue(cell));
System.out.println(value);
}
} catch (IOException e) {
e.printStackTrace();
}
table1.close();
}
/**
* 扫描表
*
* @param namespace
* @param table
* @param startRow
* @param stopRow
* @throws IOException
*/
public static void scan(String namespace, String table, String startRow, String stopRow) throws IOException {
//获取table
Table table1 = connection.getTable(TableName.valueOf(namespace, table));
//创建scan对象
Scan scan = new Scan();
//添加扫描的起止rowKey
scan.withStartRow(Bytes.toBytes(startRow));
scan.withStopRow(Bytes.toBytes(stopRow));
try {
ResultScanner scanner = table1.getScanner(scan);
for (Result result : scanner) {
Cell[] cells = result.rawCells();
for (Cell cell : cells) {
System.out.print(new
String(CellUtil.cloneRow(cell)) + "-" + new
String(CellUtil.cloneFamily(cell)) + "-" + new
String(CellUtil.cloneQualifier(cell)) + "-" + new
String(CellUtil.cloneValue(cell)) + "\t");
}
System.out.println();
;
}
} catch (IOException e) {
e.printStackTrace();
}
table1.close();
}
/**
* 扫描表（有过滤器）
*
* @param namespace
* @param table
* @param startRow
* @param stopRow
* @param columnFamily
* @param column
* @param value
*/
public static void scanWithFilter(String namespace, String table, String startRow, String stopRow, String columnFamily, String column, String value) throws IOException {
//获取table
Table table1 = connection.getTable(TableName.valueOf(namespace, table));
//创建scan对象
Scan scan = new Scan();
//添加扫描的起止rowKey
scan.withStartRow(Bytes.toBytes(startRow));
scan.withStopRow(Bytes.toBytes(stopRow));
//创建过滤器列表
FilterList filterList = new FilterList();
//创建列过滤器，作用：只保留当前列的数据
ColumnValueFilter columnValueFilter = new ColumnValueFilter(
Bytes.toBytes(columnFamily),
Bytes.toBytes(column),
CompareOperator.EQUAL,
Bytes.toBytes(value));
// // (2) 结果保留整行数据
// // 结果同时会保留没有当前列的数据
// SingleColumnValueFilter singleColumnValueFilter = new
// SingleColumnValueFilter(
// // 列族名称
// Bytes.toBytes(columnFamily),
// // 列名
// Bytes.toBytes(column),
// // 比较关系
// CompareOperator.EQUAL,
// // 值
// Bytes.toBytes(value)
// );
filterList.addFilter(columnValueFilter);
scan.setFilter(filterList);
try {
ResultScanner scanner = table1.getScanner(scan);
for (Result result : scanner) {
Cell[] cells = result.rawCells();
for (Cell cell : cells) {
System.out.print(new
String(CellUtil.cloneRow(cell)) + "-" + new
String(CellUtil.cloneFamily(cell)) + "-" + new
String(CellUtil.cloneQualifier(cell)) + "-" + new
String(CellUtil.cloneValue(cell)) + "\t");
}
System.out.println();
;
}
} catch (IOException e) {
e.printStackTrace();
}
table1.close();
}
/**
* 删除数据
* @param nameSpace
* @param table
* @param rowKey
* @param columnFamily
* @param column
* @throws IOException
*/
public static void delete(String nameSpace, String table, String rowKey, String columnFamily, String column) throws IOException {
//获取 table
Table table1 = connection.getTable(TableName.valueOf(nameSpace, table));
//创建 Delete 对象
Delete delete = new Delete(Bytes.toBytes(rowKey));
//添加删除信息
//删除单个版本（默认最新）
delete.addColumn(Bytes.toBytes(columnFamily),Bytes.toBytes(column));
// //删除所有版本
// delete.addColumns(Bytes.toBytes(columnFamily),Bytes.toBytes(column));
//删除列族
delete.addFamily(Bytes.toBytes(columnFamily));
try {
table1.delete(delete);
}catch (IOException e)
{
e.printStackTrace();
}
table1.close();
}
}
说明：本学习笔记根据基于尚硅谷课程进行整理，课程链接：hbase
未完待续~