Make Connection to postgresql - Java JDBC

Java examples for JDBC:Postgresql

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Description

Make Connection to postgresql

Demo Code



import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.PrintStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

public class Postgis_Sapp {

  public static void main(String[] args) throws FileNotFoundException {

    long startTime = 0;
    long stopTime = 0;
    Connection c = null;/*from w w w.ja  va  2 s. c o  m*/
    Statement stmt = null;
    PrintStream out = new PrintStream(new FileOutputStream("src/adbproject/Sappoutput_postgis.txt"));
    // PrintStream out1 = new PrintStream(new
    // FileOutputStream("src/adbproject/TOPoutput_vlarge_postgis.txt"));
    System.setOut(out);
    try {
      Class.forName("org.postgresql.Driver");
      c = DriverManager.getConnection("jdbc:postgresql://localhost:5432/postgres", "postgres", "mypassword");
      c.setAutoCommit(false);
      // System.out.println("Opened database successfully");
      double total;
      double used;
      FileReader reader = new FileReader("src/adbproject/Sapp_Postgis");

      BufferedReader bufferedReader = new BufferedReader(reader);
      int i = 0;
      String line;
      stmt = c.createStatement();
      ResultSet rs = null;
      while ((line = bufferedReader.readLine()) != null) {
        i++;
        long sum = 0;
        for (int cnt = 1; cnt <= 5; cnt++) {
          startTime = System.currentTimeMillis();
          total = ((double) ((double) (Runtime.getRuntime().totalMemory() / 1024) / 1024))
              - ((double) ((double) (Runtime.getRuntime().freeMemory() / 1024) / 1024));
          rs = stmt.executeQuery(line);
          used = ((double) ((double) (Runtime.getRuntime().totalMemory() / 1024) / 1024))
              - ((double) ((double) (Runtime.getRuntime().freeMemory() / 1024) / 1024));
          stopTime = System.currentTimeMillis();
          long elapsedTime = stopTime - startTime;
          System.out.println("In loop Time taken for query " + i + ": " + elapsedTime + " ms");
          sum = sum + elapsedTime;
        }
        long avgTime = sum / 5;
        System.out.println("Time taken for query " + i + ": " + avgTime + " ms");

        System.out.println();
        rs.close();

      }

      stmt.close();
      c.close();
      reader.close();
    } catch (Exception e) {
      System.err.println(e.getClass().getName() + ": " + e.getMessage());
      System.exit(0);
    }

  }
}

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