hbase-学习

hbase shell

package test;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.*;
import org.apache.hadoop.hbase.util.Bytes;

import java.io.IOException;
import java.util.List;

/**
 * @author mooojl
 * @Date 2020-10-18-8:51
 */
public class Test {
    // connection是一个重量级的对象，不能频繁去创建connection
    //connection是线程安全的
    private static Connection connection;
    private static Admin admin;
    public static void main(String[] args) throws IOException {
        getConn();
        //创建表:stusent，列蔟："Student","Course","SC"
        //createTable("stusent",new String[]{"Student","Course","SC"});
        //添加行
        //①Student
        //addRow("student","001","Student",new String[]{"S_No","S_Name","S_Sex","S_Age"},new String[]{"2015001","Zhangsan","male","23"});
        //addRow("student","002","Student",new String[]{"S_No","S_Name","S_Sex","S_Age"},new String[]{"2015003","Mary","female","22"});
        //②Course
        //addRow("student","001","Course",new String[]{"C_No","C_Name","C_Credit"},new String[]{"123001","Math","2.0"});
        //addRow("student","002","Course",new String[]{"C_No","C_Name","C_Credit"},new String[]{"123003","English","3.0"});
        //③SC
        //addRow("student","001","SC",new String[]{"SC_Sno","SC_Cno","SC_Score"},new String[]{"2015001","123001","86"});
        //addRow("student","002","SC",new String[]{"SC_Sno","SC_Cno","SC_Score"},new String[]{"2015003","123003","69"});

        //删除
        //deleteRow("student","001","Student","S_No");

        //get获取数据
        //getData("student","002","Student","S_No");
        
        //修改数据
        modifyData("student", "001", "SC","SC_Score", "100");
        closeConn();
    }
    public static void getConn() throws IOException {
        //1、使用HBaseConfiguration.create()创建Hbase配置
        Configuration configuration = HBaseConfiguration.create();
        //2、 ConnectionFactory.createConnection()创建Hbase连接
        connection = ConnectionFactory.createConnection(configuration);
        System.out.println(connection);
        //3、要创建表，需要基于Hbase连接获取admin管理对象
        admin = connection.getAdmin();
    }
    public static void closeConn() throws IOException {
        //4、使用admin.close. connection.close关闭连接
        if(admin != null){
            admin.close();
        }
        if(connection!=null){
            connection.close();
        }
    }
    /**
     * 建表。HBase的表中会有一个系统默认的属性作为主键，主键无需自行创建，默认为put命令操作中表名后第一个数据，因此此处无需创建id列
     * @param mytableName 表名
     * @param colFamily 列族名
     */
    public static void createTable(String mytableName,String[] colFamily) throws IOException {
        TableName tableName = TableName.valueOf(mytableName);
        //1、判断表是否存在
        if (admin.tableExists(tableName)){
            System.out.println("表存在");
            return;
        }else {
            //构建表
            //2、使用TableDescriptorBuilder.newBuilder构建表描述构造器
            //TableDescriptorBuilder:表描述器，描述这个表有几个列蔟、其他属性
            TableDescriptorBuilder tableDescriptorBuilder = TableDescriptorBuilder.newBuilder(tableName);
            //3、使用ColumnFamilyDescriptorBuilder.newBuilder()构建列蔟描述构造器
            //创建列蔟也需要有列蔟的描述器，需要用一个构建器来构建ColumnFamilyDescriptor
            //经常会使用到一个工具类:Bytes (hbase包下的Bytes工具类）
            //这个工具类可以将字符串、long.double类型转换成byte[]数组
            //也可以将byte[]数组转换为指定类型
            for (String str : colFamily) {
                ColumnFamilyDescriptorBuilder columnFamilyDescriptorBuilder = ColumnFamilyDescriptorBuilder.newBuilder(Bytes.toBytes(str));
                //4、构建列蔟描述，构建表描述
                ColumnFamilyDescriptor cfdes = columnFamilyDescriptorBuilder.build();
                //建立表和列蔟的关联
                tableDescriptorBuilder.setColumnFamily(cfdes);
            }
            TableDescriptor tableDescriptor = tableDescriptorBuilder.build();
            //5、创建表
            admin.createTable(tableDescriptor);
        }
        closeConn();
    }
    /**
     * 向某一行的某一列插入数据
     * @param tableName 表名
     * @param rowKey 行键
     * @param colFamily 列族名
     * @param col 列名（如果其列族下没有子列，此参数可为空）
     * @param val 值
     */
    public static void addRow(String tableName, String rowKey,String colFamily,String[] col,String[] val) throws IOException {
        TableName tablename = TableName.valueOf(tableName);
        //1 使用Hbase连接获取Htable
        Table table = connection.getTable(tablename);
        //2 构建ROWKEY、列蔟名、列名
        //3 构建Put对象（对应put命令）
        Put put = new Put(Bytes.toBytes(rowKey));
        for (int i=0;i<col.length;i++){
            //4 添加列、值
            put.addColumn(Bytes.toBytes(colFamily),Bytes.toBytes(col[i]),Bytes.toBytes(val[i]));
        }
        //5 使用Htable表对象执行put操作
        table.put(put);
        //6 关闭Htable表对象
        //HTable是一个轻量级的对象，可以经常创建
        //HTable它是一个非线程安全的API
        table.close();
    }
    /**
     * 删除数据
     * @param tableName 表名
     * @param rowKey 行键
     * @param colFamily 列族名
     * @param col 列名
     *
     */
    public static void deleteRow(String tableName,String rowKey,String colFamily,String col) throws IOException {
        TableName tablename = TableName.valueOf(tableName);
        Table table = connection.getTable(tablename);
        Delete delete = new Delete(Bytes.toBytes(rowKey));
        //Delete delete = new Delete(rowKey.getBytes());
        //删除指定列族的所有数据
        delete.addFamily(colFamily.getBytes());
        //删除指定列的数据
        //delete.addColumn(colFamily.getBytes(), col.getBytes());
        table.delete(delete);
        table.close();
    }
    /**
     * 删除指定表
     * @param tableName 表名
     */
    public static void deleteTable(String tableName) throws IOException {
        TableName tablename = TableName.valueOf(tableName);
        if (admin.tableExists(tablename)){
            //2、如果存在，则禁用表
            admin.disableTable(tablename);
            //3、删除
            admin.deleteTable(tablename);
        }
    }

    /**
     * 根据行键rowkey查找数据
     * @param tableName 表名
     * @param rowKey    行键
     * @param colFamily 列族名
     * @param col       列名
     */
    public static void getData(String tableName, String rowKey, String colFamily, String col) throws IOException {
        TableName tablename = TableName.valueOf(tableName);
        // 1.获取HTable
        Table table = connection.getTable(tablename);
        //2.使用rowkey构建Get对象
        Get get = new Get(Bytes.toBytes(rowKey));
        //get.addFamily(Bytes.toBytes(colFamily));
        get.addColumn(colFamily.getBytes(),col.getBytes());
        //3.执行get请求
        Result result = table.get(get);
        //4.获取所有单元格
        List<Cell> cellList = result.listCells();
        byte[] rowkey = result.getRow();
        System.out.println("rowkey"+Bytes.toString(rowkey));;
        //6.迭代单元格列表
        for (Cell cell : cellList) {
            //将字节数组转换为字符串
            //获取列蔟名称
            String cf = Bytes.toString(cell.getFamilyArray(), cell.getFamilyOffset(), cell.getFamilyLength());
            //获取列名称
            String columnName = Bytes.toString(cell.getQualifierArray(), cell.getQualifierOffset(), cell.getQualifierLength());
            //获取值
            String value = Bytes.toString(cell.getValueArray(), cell.getValueOffset(), cell.getValueLength());
            System.out.println(cf +":" +columnName+"->"+value);
        }
        table.close();
    }

    //修改表
    public static void modifyData(String tableName,String rowKey,String colFamily,String column,String val) throws IOException {
        TableName tablename = TableName.valueOf(tableName);
        Table table = connection.getTable(tablename);
        long ts = 0;
        Put put = new Put(Bytes.toBytes(rowKey));
        Scan scan = new Scan();
        ResultScanner resultScanner = table.getScanner(scan);
        for (Result r : resultScanner) {
            for (Cell cell : r.getColumnCells(rowKey.getBytes(), column.getBytes())) {
                ts = cell.getTimestamp();
            }
        }
        put.addColumn(rowKey.getBytes(),column.getBytes(),ts,val.getBytes());
        table.put(put);
        table.close();
    }
}