Presto使用JDBC連接集羣代碼-呂信（原創）

----------------------------------------------程序1： 遍歷某個表----------------------------------------------

package jd.com.dawn;

import java.sql.DriverManager;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.util.TimeZone;

import com.facebook.presto.jdbc.PrestoConnection;

import com.facebook.presto.jdbc.PrestoStatement;

public class PrestoClient {

 public static void printRow(ResultSet rs,int[]types) throws SQLException

 {

  for(int i=0;i<types.length;i++)

   System.out.print(rs.getObject(i+1));

  System.out.println("");

 }

 public static void connect() throws SQLException {

    //設置時區，這裏必需要設置

  TimeZone.setDefault(TimeZone.getTimeZone("Asia/Shanghai"));

  try {

   Class.forName("com.facebook.presto.jdbc.PrestoDriver");

  } catch (ClassNotFoundException e) {

   e.printStackTrace();

  }

  PrestoConnection connection = null;

  try {

   //鏈接字符串中的hive是catalog名字，sys是schema名字，ddd是用戶名，這個用戶名根據實際業務本身設定，用來標示執行sql的用戶，可是不會經過該用戶名進行身份認證，可是必需要寫。密碼直接指定爲null

   connection = (PrestoConnection) DriverManager.getConnection(

     "jdbc:presto://Coordinator IP地址:Coordinator端口號/hive/sys","ddd",null);

  } catch (SQLException e) {

   e.printStackTrace();

  }

  PrestoStatement statement = null;

  try {

   

   statement = (PrestoStatement) connection.createStatement();

  } catch (SQLException e) {

   e.printStackTrace();

  }

  String query = "select * from node";

  ResultSet rs = null;

  try {

   rs = statement.executeQuery(query);

  } catch (SQLException e) {

   e.printStackTrace();

  }

  int cn=rs.getMetaData().getColumnCount();

  int[] types=new int[cn];

  for(int i=1;i<=cn;i++)

  {

   types[i-1]=rs.getMetaData().getColumnType(i);

  }

 

  try {

   while (rs.next()) {

    printRow(rs,types);

   }

  } catch (SQLException e) {

   e.printStackTrace();

  }

 }

 public static void main(String[] args) throws ClassNotFoundException,

   SQLException {

  connect();

 }

}

----------------------------------------------程序2： SQL查詢併發性說明----------------------------------------------

package test;

import java.sql.DriverManager;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;

import java.util.Properties;

import com.facebook.presto.jdbc.PrestoConnection;

public class PrestoJdbcTest

{

public static void main(String[] args)

{

Properties properties = new Properties();

properties.setProperty("user", "hadp");

try {

PrestoConnection connect = (PrestoConnection) DriverManager.getConnection("jdbc:presto://Coordinator地址:端口/hive/employees", "Presto用戶名", null);

connect.setTimeZoneId("UTC");

String sql1 = "show tables";

String sql2 = "select * from dept_emp limit 5";

Statement stat = connect.createStatement();

//對如下代碼說明以下：

//若是不經過兩個while循環一次對rs1和rs2進行遍歷，而只是執行ResultSet rs1 = stat.executeQuery(sql1);和ResultSet rs2 = stat.executeQuery(sql2); 那麼這兩個查詢會並行執行。

//下面使用兩個while循環的目的是爲了保證sql2在sql1執行完畢以後在執行。

ResultSet rs1 = stat.executeQuery(sql1);

while(rs1.next()) {

String int1 = rs1.getString(1);

System.out.println(int1);

}

ResultSet rs2 = stat.executeQuery(sql2);

while(rs2.next()) {

String str = rs2.getString(1);

System.out.println(str);

}

}

catch (SQLException e) {

e.printStackTrace();

}

}

}