Example Importing and Exporting Data Through Local Files

import java.sql.Connection;
import java.sql.DriverManager;
import java.io.IOException;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.sql.SQLException;
import org.postgresql.copy.CopyManager;
import org.postgresql.core.BaseConnection;

public class Copy{

     public static void main(String[] args)
     {
      String urls = new String("jdbc:postgresql://10.180.155.74:8000/postgres"); // Database URL
      String username = new String("jack");            // Username
      String password = new String("Gauss@123");             // Password
      String tablename = new String("migration_table"); // Table information
      String tablename1 = new String("migration_table_1"); // Table information
      String driver = "org.postgresql.Driver";
      Connection conn = null;

      try {
            Class.forName(driver);
            conn = DriverManager.getConnection(urls, username, password);
          } catch (ClassNotFoundException e) {
               e.printStackTrace(System.out);
          } catch (SQLException e) {
               e.printStackTrace(System.out);
          }

      // Export the query result of SELECT * FROM migration_table to the local file d:/data.txt.
      try {
     copyToFile(conn, "d:/data.txt", "(SELECT * FROM migration_table)");
   } catch (SQLException e) {
  k
  e.printStackTrace();
   } catch (IOException e) {

  e.printStackTrace();
   }
      // Import data from the d:/data.txt file to the migration_table_1 table.
      try {
      copyFromFile(conn, "d:/data.txt", tablename1);
   } catch (SQLException e) {
         e.printStackTrace();
 } catch (IOException e) {

  e.printStackTrace();
 }

      // Export the data from the migration_table_1 table to the d:/data1.txt file.
      try {
      copyToFile(conn, "d:/data1.txt", tablename1);
   } catch (SQLException e) {

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


  e.printStackTrace();
 }
     }
  // Use copyIn to import data from a file to the database.
  public static void copyFromFile(Connection connection, String filePath, String tableName)
         throws SQLException, IOException {

     FileInputStream fileInputStream = null;

     try {
         CopyManager copyManager = new CopyManager((BaseConnection)connection);
         fileInputStream = new FileInputStream(filePath);
         copyManager.copyIn("COPY " + tableName + " FROM STDIN", fileInputStream);
     } finally {
         if (fileInputStream != null) {
             try {
                 fileInputStream.close();
             } catch (IOException e) {
                 e.printStackTrace();
             }
         }
     }
 }

  // Use copyOut to export data from the database to a file.
  public static void copyToFile(Connection connection, String filePath, String tableOrQuery)
          throws SQLException, IOException {

      FileOutputStream fileOutputStream = null;

      try {
          CopyManager copyManager = new CopyManager((BaseConnection)connection);
          fileOutputStream = new FileOutputStream(filePath);
          copyManager.copyOut("COPY " + tableOrQuery + " TO STDOUT", fileOutputStream);
      } finally {
          if (fileOutputStream != null) {
              try {
                  fileOutputStream.close();
              } catch (IOException e) {
                  e.printStackTrace();
              }
          }
      }
  }
}