Kotlin prepared statement (SQL)

sample.kt

package com.improve_future.sample

import java.io.Closeable
import java.sql.DriverManager
import java.sql.Statement
import java.text.SimpleDateFormat

class Connection(private val coreConnection: java.sql.Connection) :
    java.sql.Connection by coreConnection, Closeable {

    override fun close() {
        coreConnection.close()
    }

    override fun createStatement(): Statement {
        return coreConnection.createStatement()
    }
}

fun connect(): Connection {
    val url = "jdbc:postgresql://HOST:5432/DB_NAME"
    val user = "USER_NAME"
    val password = "PASSWORD"

    val c = DriverManager.getConnection(url, user, password)
    c.autoCommit = false
    return Connection(c)
}

fun main(args: Array<String>) {
    example()
}

fun example() {
    connect().use {
        val st1 = it.createStatement()
        val resultSet1 = st1.executeQuery(
            """
            SELECT a, b
              FROM table_name
             WHERE value = 5
             ORDER BY id
            """.trimIndent()
        }
        while (resultSet1.next()) {
            val a = resultSet1.getLong("a")   // same as resultSet1.getLong(1)
            val b = resultSet1.getString("b") // same as resultSet1.getString(2)
            // process
        }
        resultSet1.close()
        st1.close()
          
        val st2 = it.prepareStatement(
            """
            SELECT a, b
              FROM table_name
             WHERE value = 5
               AND filter_1 = ?
               AND filter_2 = ?
             ORDER BY id
            """.trimIndent()
        )
        st2.setLong(1, 1L)
        st2.setString(2, "text")
        resultSet2 = st2.executeQuery()
        while (resultSet2.next()) {
            val a = resultSet1.getLong("a")   // same as resultSet1.getLong(1)
            val b = resultSet1.getString("b") // same as resultSet1.getString(2)
            // process
        }
        resultSet2.close()
        st2.close()
    }
}