您只能绑定PreparedStatement中的值，不能绑定语法元素或对象名(在这种情况下为表名).您将不得不求助于字符串操作:

You can only bind values in a PreparedStatement, not syntactic elements or object names (in this case, the table name). You'll have to resort to string manipulation:

final String query = String.format("SELECT COUNT(*) FROM %s", tablename);
final PreparedStatement preparedStatement = connection.prepareStatement(query);
final ResultSet resultSet = preparedStatement.executeQuery();

请注意，此查询中没有占位符，因此使用PreparedStatement相对于普通的Statement是否真的有任何优势是令人怀疑的.

Note that there are no placeholders in this query, so it's questionable whether there's really any advantage in using a PreparedStatement as opposed to a plain old Statement.