public <T> void insertWithCopy(String tableName, List<String> columns, List<T> entities, CopyMapper<T> mapper, DataSource dataSource) { if (CollectionUtils.isEmpty(entities)) { throw new IllegalArgumentException("No entities provided"); } if (CollectionUtils.isEmpty(columns)) { throw new IllegalArgumentException("No columns provided"); } String sql = COPY_STMT.formatted(tableName, String.join(", ", columns)); try (Connection connection = dataSource.getConnection(); StringWriter writer = new StringWriter()) { PGConnection pgConnection = connection.unwrap(PGConnection.class); CopyManager copyManager = new CopyManager((BaseConnection) pgConnection); for (T entity : entities) { String[] row = mapper.toCopyRow(entity); if (row.length != columns.size()) { throw new IllegalStateException("Mismatch between rows (%d) and columns (%d)" .formatted(row.length, columns.size())); } writer.write(String.join("\t", row)); writer.write("\n"); } copyManager.copyIn(sql, new StringReader(writer.toString())); } catch (Exception e) { throw new RuntimeException("Error while inserting", e); } }

import de.bytefish.pgbulkinsert.mapping.AbstractMapping; public class CustomerMapping extends AbstractMapping<Customer> { public CustomerMapping() { super("public", "customer"); mapLong("id", Customer::getId); mapText("first_name", Customer::getFirstName); mapText("last_name", Customer::getLastName); mapText("country", Customer::getCountry); mapText("address", Customer::getAddress); mapText("city", Customer::getCity); mapTimeStamp("creation_date", Customer::getCreationDate); mapTimeStamp("update_date", Customer::getUpdateDate); } }

public void bulkInsert(List<Customer> customers) { PgBulkInsert<Customer> bulkInsert = new PgBulkInsert<>(new CustomerMapping()); try (Connection conn = dataSource.getConnection()) { bulkInsert.saveAll(PostgreSqlUtils.getPGConnection(conn), customers); } catch (Exception e) { throw new RuntimeException("Error while bulk inserting", e); } }