A simple java class to get PostgreSQL COPY content from STDOUT to compressed file

DataCopyManager.java

package br.com.michelmilezzi.database.data;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

import org.postgresql.PGConnection;
import org.postgresql.copy.PGCopyInputStream;

public final class DataCopyManager {

	private static final byte[] BUFFER = new byte[1024*16];

	private DataCopyManager() {
	}

	public static void copyDataToCompressedCSVFile(final Connection conn, 
			final String sql, 
			final String compressedFilename, 
			final File destinationFile) throws SQLException, IOException {

		final PGConnection pgConn = prepareConnection(conn);

		try (PGCopyInputStream originCopyInStream = new PGCopyInputStream(pgConn, getCopyToCSVCommand(sql));
				ZipOutputStream zos = new ZipOutputStream(new FileOutputStream(destinationFile))) {
			ZipEntry ze = new ZipEntry(compressedFilename);
			zos.putNextEntry(ze);
			int len;
			while ((len = originCopyInStream.read(BUFFER)) > 0) {
				zos.write(BUFFER, 0, len);
			}
			zos.closeEntry();
		}

	}

	private static String getCopyToCSVCommand(final String sql) {
		return String.format("COPY (%s) TO STDOUT WITH CSV ENCODING 'UTF-8'", sql);
	}

	private static PGConnection prepareConnection(final Connection conn) throws SQLException {
		return conn.unwrap(PGConnection.class);
	}

}