import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.*;
import org.apache.hadoop.hbase.client.*;
import
java.io.IOException;
public class ExampleForHbase{
public static Configuration configuration;
public static Connection connection;
public static Admin admin;
//主函数中的语句请逐句执行，只需删除其前的//即可，如：执行insertRow时请将其他语句注释
public static void main(String[] args)throws IOException{
createTable("Score",new String[]{"Studnet","Course","SC"});
}
//建立连接
public static void init(){
configuration = HBaseConfiguration.create();
configuration.set("hbase.rootdir","hdfs://localhost:9000/hbase");
try{
connection = ConnectionFactory.createConnection(configuration);
admin = connection.getAdmin();
}catch (IOException e){
e.printStackTrace();
}
}
//关闭连接
public static void close(){
try{
if(admin != null){
admin.close();
}
if(null != connection){
connection.close();
}
}catch (IOException e){
e.printStackTrace();
}
}
/**
* 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
* @throws IOException
*/
public static void createTable(String tableName,String[] fields) throws IOException {
init();
TableName tablename = TableName.valueOf(tableName);
if(admin.tableExists(tablename)){
System.out.println("table is exists!");
admin.disableTable(tablename);
admin.deleteTable(tablename);//删除原来的表
}else{
HTableDescriptor hTableDescriptor = new HTableDescriptor(tablename);
for(String str:fields){
HColumnDescriptor hColumnDescriptor = new HColumnDescriptor(str);
hTableDescriptor.addFamily(hColumnDescriptor);
}
admin.createTable(hTableDescriptor);
System.out.println("create table success");
}
close();
}
}
