String sql =
          "SET NOCOUNT ON; "
        + "DECLARE @id INT = ?; "
        + "DECLARE @col2 VARCHAR(10) = ?; "
        + "DECLARE @col3 VARCHAR(10) = ?; "
        + "INSERT INTO mytable "
        + "SELECT @id, @col2, @col3 "
        + "WHERE NOT EXISTS (SELECT 1 FROM mytable "
        + "                  WHERE id = @id AND col2 = @col2 AND col3 = @col3);";
PreparedStatement ps = conn.prepareStatement(sql);
for (int i = 0; i < 4; i++) {
    ps.setInt(1, i);
    ps.setString(2, String.format("foo%s", i));
    ps.setString(3, String.format("bar%s", i));
    ps.addBatch();
}
ps.executeBatch();