2023.11.12日报

今天主要在做大数据实验三，有个问题记录一下 代码如下

package Test3;
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 ExampleForHBase {
    public static Configuration configuration;
    public static Connection connection;
    public static Admin admin;
    public static void main(String[] args)throws IOException{
        init();//主要操作就是为了连接到数据库hbase
        createTable("student",new String[]{"score"});//创建表，shell命令：create '表名'，'列族名1'，'列族名2'，'列族名3' ...
        insertData("student","zhangsan","score","English","69"); //shell命令： put 'student'，'张三'，'score：English'，'69'
        insertData("student","zhangsan","score","Math","86");
        insertData("student","zhangsan","score","Computer","77");
        getData("student", "zhangsan", "score","English");
        close();
    }

    public static void init() {
        System.out.println("2");
        configuration = HBaseConfiguration.create();
        System.out.println("1");
        configuration.set("hbase.rootdir", "hdfs://192.168.88.151:8020/base");
        configuration.set("hbase.zookeeper.quorum","192.168.88.151,192.168.88.152,192.168.88.153");
        configuration.set("hbase.zookeeper.property.clientPort","2181");
        try {
            connection = ConnectionFactory.createConnection(configuration);
            admin = connection.getAdmin();
            System.out.println(3);
            System.out.println("HBase连接已建立。");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

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

    public static void createTable(String myTableName,String[] colFamily) throws IOException {
        System.out.println("5");
        TableName tableName = TableName.valueOf(myTableName);
        if(admin.tableExists(tableName)){
            System.out.println("talbe is exists!");
        }else {
            TableDescriptorBuilder tableDescriptor = TableDescriptorBuilder.newBuilder(tableName);
            for(String str:colFamily){
                ColumnFamilyDescriptor family =
                        ColumnFamilyDescriptorBuilder.newBuilder(Bytes.toBytes(str)).build();
                tableDescriptor.setColumnFamily(family);
            }
            admin.createTable(tableDescriptor.build());
        }
    }

    public static void insertData(String tableName,String rowKey,String colFamily,String col,String val) throws IOException {
        Table table = connection.getTable(TableName.valueOf(tableName));
        Put put = new Put(rowKey.getBytes());
        put.addColumn(colFamily.getBytes(),col.getBytes(), val.getBytes());
        table.put(put);
        table.close();
    }

    public static void getData(String tableName,String rowKey,String colFamily, String col)throws  IOException{
        Table table = connection.getTable(TableName.valueOf(tableName));
        Get get = new Get(rowKey.getBytes());
        get.addColumn(colFamily.getBytes(),col.getBytes());
        Result result = table.get(get);
        System.out.println(new String(result.getValue(colFamily.getBytes(),col==null?null:col.getBytes())));
        table.close();
    }
}

其实代码很容易理解，主要是连接hbase的时候，网上很多代码是没有关于zookeeper的两行配置的，我一开始也没有进行配置，所以会报错

然后这两个配置项，第一个可以在hbase的安装路径下的conf的hbase-site.xml找到，另一个可以在zookeeper的安装路径下的conf下的zoo.cfg下，搜client就能找到

配置完成之后就可以成功实现了