每日日报--Hbase的学习(5)

完成内容：

1.  Hbase的API操作2

 

package Test;

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


import java.io.IOException;

public class Test {
    private static Connection connection = null;
    private static Admin admin = null;

    static {
        try {
            //1.获取配置文件信息
            Configuration configuration = HBaseConfiguration.create();
            configuration.set("hbase.zookeeper.quorum","centos01,centos02,centos03");

            //2.创建连接对象
            connection = ConnectionFactory.createConnection(configuration);

            //3.创建Admin对象
            admin = connection.getAdmin();
        }
        catch (IOException e){
            e.printStackTrace();
        }
    }

    //判断表是否存在
    public static boolean isTableExist(String tableName) throws IOException {

        /*
        //1.获取配置文件信息
        //HBaseConfiguration configuration = new HBaseConfiguration();
        Configuration configuration = HBaseConfiguration.create();
        configuration.set("hbase.zookeeper.quorum","centos01,centos02,centos03");

        //2.获取管理员对象
        //HBaseAdmin admin = new HBaseAdmin(configuration);
        Connection  connection = ConnectionFactory.createConnection(configuration);
        Admin admin = connection.getAdmin();
        */

        //3.判断表是否存在
        //boolean exist = admin.tableExists(tableName);
        boolean exist = admin.tableExists(TableName.valueOf(tableName));

        /*
        //4.关闭连接
        admin.close();
        */

        //5.返回结果
        return exist;
    }

    //创建表
    public static void CreateTable(String tableName,String... cfs) throws IOException {
        //1.判断是否存在列族信息
        if (cfs.length <= 0){
            System.out.println("请设置列族信息");
            return;
        }

        //2.判断表是否存在
        if(isTableExist(tableName)) {
            System.out.println("表已存在!");
            return;
        }

        //3.创建表描述器
        HTableDescriptor hTableDescriptor = new HTableDescriptor(tableName.valueOf(tableName));

        //4.循环添加列族信息
        for (String cf : cfs) {
            //5.创建列族描述器
            HColumnDescriptor hColumnDescriptor = new HColumnDescriptor(cf);


            //6.添加具体的列族信息
            hTableDescriptor.addFamily(hColumnDescriptor);
        }

        //7.创建表
        admin.createTable(hTableDescriptor);
    }

    //创建命名空间
    public static void CreateNameSpace(String ns){
        //1.创建命名空间描述期
        NamespaceDescriptor namespaceDescriptor = NamespaceDescriptor.create(ns).build();

        //2.创建命名空间
        try{
            admin.createNamespace(namespaceDescriptor);
        }
        catch (NamespaceExistException e){
            System.out.println(ns+"命名空间已存在");
        }
        catch (IOException e){
            e.printStackTrace();
        }
    }

    //插入数据
    public static void PutData(String tableName,String rowKey,String cf,String cn,String value) throws IOException {
        //1.获取表对象
        Table table = connection.getTable(TableName.valueOf(tableName));

        //2.创建PUT对象
        Put put = new Put(Bytes.toBytes(rowKey));

        //3.给PUT对象赋值
        put.addColumn(Bytes.toBytes(cf),Bytes.toBytes(cn),Bytes.toBytes(value));

        //4.插入数据
        table.put(put);

        //5.关闭表连接
        table.close();
    }

    //删除表
    public static void DeleteTable(String tableName) throws IOException {
        //1.判断表是否存在
        if(!isTableExist(tableName)){
            System.out.println(tableName+"表不存在!");
            return;
        }

        //2.表下线
        admin.disableTable(TableName.valueOf(tableName));

        //3.删除表
        admin.deleteTable(TableName.valueOf(tableName));
    }

    //关闭进程
    public static void close(){
        if(admin != null) {
            try{
                admin.close();
            }
            catch (IOException e){
                e.printStackTrace();
            }
        }

        if (connection != null) {
            try{
                connection.close();
            }
            catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    public static void main(String[] args) throws IOException {
        //1.测试表是否存在
        System.out.println(isTableExist("lalala"));

        //2.创建表测试
        //CreateTable("lalala","info1","info2");

        //3.删除表测试
        DeleteTable("lalala");

        //4.测试表是否存在
        System.out.println(isTableExist("lalala"));

        //5.创建数据

        //关闭资源
        close();
    }

}

遇到问题：

 无

目标：继续学习hadoop