azure - 可以在 HDInsight 中运行的 Hadoop 作业的驱动程序方法中访问 Azure SQL 数据库吗？

Question

我想开发在 HDInsight 上运行的 Hadoop 应用程序。在我的应用程序的驱动程序方法中，我需要从 Azure SQL 数据库获取一些信息。我想知道是否可以在我的 Hadoop 作业的驱动程序方法中查询 Azure SQL 数据库？

Answer 1

您可以使用 java.sql 类访问 Azure SQL 数据库，但您可能需要将头节点 IP 添加到数据库防火墙规则中。

package org.microsoft.andrewmoll.SqlExample;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

/**
 * Hello world!
 *
 */
public class SQLExample 
{
    public static class TokenizerMapper
    extends Mapper<Object, Text, Text, IntWritable>{
//You should put some awesome map logic here
   }



public static class IntSumReducer
    extends Reducer<Text,IntWritable,Text,IntWritable> {
    //You should put some awesome reducer logic here
}

public static void main(String[] args) throws Exception {
 Configuration conf = new Configuration();

 String jobName = getData();
 System.out.println(jobName);
 Job job = Job.getInstance(conf, jobName);
 job.setJarByClass(SQLExample.class);
 job.setMapperClass(TokenizerMapper.class);
 job.setCombinerClass(IntSumReducer.class);
 job.setReducerClass(IntSumReducer.class);
 job.setOutputKeyClass(Text.class);
 job.setOutputValueClass(IntWritable.class);
 System.exit(job.waitForCompletion(true) ? 0 : 1);
}

public static String getData()
{

     String driver = "com.microsoft.sqlserver.jdbc.SQLServerDriver";
     String url = "jdbc:sqlserver:<servername>.database.windows.net;DatabaseName=<dbname>";
     String username = "DarthMoll";
     String password = "Luke,Iamnotyourfather";
     try {
         /* Load database driver */
         Class.forName(driver);
         /* Establish database connection */
         Connection con = DriverManager.getConnection(url, username, password);
         /* Run query */
         PreparedStatement stmt = con.prepareStatement("select top 1 * from dbo.SithWarriors");
         /* Get return result */
         ResultSet resultset = stmt.executeQuery();
         /* get users first name  */
         String result = resultset.getString("FirstName");
         /* Close result set */
         resultset.close();
         /* Close database connection */
         con.close();
         return result;

     } catch (Exception e) {
         e.printStackTrace();
     }


    return "Implement Some Throwable Here";
}
}

如果可能，我建议将数据存储在 blob 中并使用 Java SDK 访问数据。使您不必担心头节点 IP 地址。