How to map a ResultSet with unknown amount of columns to a List and display it in a HTML table?

Question

I have created a Database Application using Netbeans, GlassFish and JavaDB. Now my controller Servlet code executes some dynamic SQL queries and get back a Result Set (or I

Answer 1

You can use Map to represent a "dynamic" row, which is iterable in . You can use ResultSetMetaData to collect information about the columns such as the column count and the column labels.

So, this mapping should do:

List> rows = new ArrayList>();
ResultSetMetaData metaData = resultSet.getMetaData();
int columnCount = metaData.getColumnCount();

while (resultSet.next()) {
    Map columns = new LinkedHashMap();

    for (int i = 1; i <= columnCount; i++) {
        columns.put(metaData.getColumnLabel(i), resultSet.getObject(i));
    }

    rows.add(columns);
}

You can display it in JSP as follows: