// ReadDBServlet import java.io.*; import javax.servlet.*; import javax.servlet.http.*; import java.sql.*; public class ReadDBServlet extends HttpServlet { final static String url = "jdbc:postgresql://ellemose.dina.kvl.dk/gp"; final static String usr = "gp"; final static String pwd = "..."; Connection db; // The connection to the database Statement st; // A statement to run queries with // Åbn forbindelsen til databasen når servlet-objektet skabes public void init(ServletConfig config) throws ServletException { super.init(config); try { Class.forName("postgresql.Driver"); db = DriverManager.getConnection(url, usr, pwd); st = db.createStatement(); } catch (ClassNotFoundException e) { System.out.println("Cannot find the Postgresql driver"); } catch (SQLException e) { System.out.println("Database error: " + e); } } // Luk forbindelsen til databasen når servlet-objektet nedlægges public void destroy() { try { st.close(); db.close(); } catch (SQLException e) { System.out.println("Database error: " + e); } } // Læs det aktuelle indhold fra tabellen Student public void doGet(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException { res.setContentType("text/html"); ServletOutputStream out = res.getOutputStream(); try { String query = "SELECT * FROM student ORDER BY fornavn"; st.execute(query); out.println(""); out.println("

Tabellen Student

"); out.println("

Fornavn	Efternavn	Studienr"); ResultSet rs = st.getResultSet(); while (rs.next()) { String enavn = rs.getString("efternavn"); String fnavn = rs.getString("fornavn"); String stdnr = rs.getString("studienummer"); out.print("
" + fnavn + "	" + enavn + "	" + stdnr); } out.println("

"); } catch (SQLException e) { System.out.println("Database error: " + e); } } }