HBase常用的JAVA API操作
为了方便以后查看,总结了一些常用的java操作hbase的代码:
package com.mcq; import static org.hamcrest.CoreMatchers.describedAs; import static org.hamcrest.CoreMatchers.nullValue; import java.io.IOException; import java.io.PushbackInputStream; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.hbase.Cell; import org.apache.hadoop.hbase.CellScannable; import org.apache.hadoop.hbase.CellUtil; import org.apache.hadoop.hbase.HBaseConfiguration; import org.apache.hadoop.hbase.HColumnDescriptor; import org.apache.hadoop.hbase.HTableDescriptor; import org.apache.hadoop.hbase.TableName; import org.apache.hadoop.hbase.client.Admin; import org.apache.hadoop.hbase.client.Connection; import org.apache.hadoop.hbase.client.ConnectionFactory; import org.apache.hadoop.hbase.client.Delete; import org.apache.hadoop.hbase.client.Get; import org.apache.hadoop.hbase.client.HTable; import org.apache.hadoop.hbase.client.Put; import org.apache.hadoop.hbase.client.Result; import org.apache.hadoop.hbase.client.ResultScanner; import org.apache.hadoop.hbase.client.Scan; import org.apache.hadoop.hbase.client.Table; import org.apache.hadoop.hbase.util.Bytes; public class TestHbase { private static Admin admin = null; private static Connection connection = null; private static Configuration conf = null; static { // HBase配置文件 conf = HBaseConfiguration.create(); conf.set("hbase.zookeeper.quorum", "192.168.1.103"); // 获取连接对象 try { connection = ConnectionFactory.createConnection(conf); // 获取HBase管理员对象 admin = connection.getAdmin(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } private static void close(Connection conn, Admin admin) throws IOException { if (conn != null) { conn.close(); } if (admin != null) { admin.close(); } } // 判断表是否存在 public static boolean tableExist(String tableName) throws IOException { boolean tableExists = admin.tableExists(TableName.valueOf(tableName)); return tableExists; } // 创建表 public static void createTable(String tableName, String... cfs) throws IOException { if (tableExist(tableName)) { System.out.println("表已存在"); return; } // cfs是列族,官方建议一个表一个,但可以有多个 // 创建表描述器 HTableDescriptor hTableDescriptor = new HTableDescriptor(TableName.valueOf(tableName)); for (String cf : cfs) { // 创建列描述器 HColumnDescriptor hColumnDescriptor = new HColumnDescriptor(cf); // hColumnDescriptor.setMaxVersions(3);//设置版本数 hTableDescriptor.addFamily(hColumnDescriptor); } // 创建表操作 admin.createTable(hTableDescriptor); } // 删除表 public static void deleteTable(String tableName) throws IOException { if (!tableExist(tableName)) { System.out.println("表不存在"); return; } // 使表不可用(下线) admin.disableTable(TableName.valueOf(tableName)); // 执行删除操作 admin.deleteTable(TableName.valueOf(tableName)); System.out.println("表已删除"); } // 增、改 public static void putData(String tableName, String rowKey, String cf, String cn, String value) throws IOException { // 获取表对象 // HTable table=new HTable(conf,TableName.valueOf(tableName)); 已过时 Table table = connection.getTable(TableName.valueOf(tableName)); // 创建put对象 Put put = new Put(Bytes.toBytes(rowKey)); // 添加数据 put.addColumn(Bytes.toBytes(cf), Bytes.toBytes(cn), Bytes.toBytes(value)); // 执行添加操作 table.put(put); } // 删 public static void delete(String tableName, String rowKey, String cf, String cn) throws IOException { // 获取table对象 Table table = connection.getTable(TableName.valueOf(tableName)); // 创建delete对象 Delete delete = new Delete(Bytes.toBytes(rowKey));// 删除整个列族 delete.addColumns(Bytes.toBytes(cf), Bytes.toBytes(cn));// 删除所有版本 // delete.addColumn(Bytes.toBytes(cf), Bytes.toBytes(cn));不推荐,只删除最新的版本 // 执行删除操作 table.delete(delete); table.close(); } // 查——全表扫描,只能获取最新版本 public static void scanTable(String tableName) throws IOException { // 获取table对象 Table table = connection.getTable(TableName.valueOf(tableName)); // 构建扫描器 Scan scan = new Scan(); ResultScanner resultScanner = table.getScanner(scan); // 遍历数据并打印 for (Result result : resultScanner) { // rowkey Cell[] cells = result.rawCells(); for (Cell cell : cells) { // cell System.out.println("RK:" + Bytes.toString(CellUtil.cloneRow(cell)) + ",CF:" + Bytes.toString(CellUtil.cloneFamily(cell)) + ",CN:" + Bytes.toString(CellUtil.cloneQualifier(cell)) + ",VALUE:" + Bytes.toString(CellUtil.cloneValue(cell))); } } table.close(); } // 查——获取指定列族 public static void getData(String tableName, String rowKey, String cf, String cn) throws IOException { Table table = connection.getTable(TableName.valueOf(tableName)); Get get = new Get(Bytes.toBytes(rowKey)); get.addColumn(Bytes.toBytes(cf), Bytes.toBytes(cn)); // get.addFamily(cf); // get.setMaxVersions();//不传参默认是表结构内的maxversions get.setMaxVersions(2); Result result = table.get(get); Cell[] cells = result.rawCells(); for (Cell cell : cells) { // cell System.out.println("RK:" + Bytes.toString(CellUtil.cloneRow(cell)) + ",CF:" + Bytes.toString(CellUtil.cloneFamily(cell)) + ",CN:" + Bytes.toString(CellUtil.cloneQualifier(cell)) + ",VALUE:" + Bytes.toString(CellUtil.cloneValue(cell))); } } public static void main(String[] args) throws IOException { // 判断表是否存在 // System.out.println(tableExist("student")); // System.out.println(tableExist("staff")); // 创建表 // createTable("staff", "info"); // System.out.println(tableExist("staff")); // 删除表 // deleteTable("staff"); // 增、改 // putData("student", "1001", "info", "name", "mcq"); // 删 // delete("student", "1001", "info", "name"); // 查——全表扫描 // scanTable("student"); //查——获取指定列族 getData("student", "1001","info","name"); // 关闭资源 close(connection, admin); } }