Accessing A DB From A JSP

Question

Hi,
I've been using the code at the bottom of this message to access a database. I've been having some trouble though when the user stops the browser session mid way through a page loading. Occasionally it can cause the web server to crash. I'm guessing a connection must be left open somewhere, and that is causing the problem. Has anyone got any advice on ways I can avoid this?
Cheers,
Lee
import java.sql.*;
import java.util.*;
public class DBAccess {
  // Username, password & URL for accessing tables
  private String uname = "username";
  private String pword = "password";
  private String url = "Conn URL here";
  // Declare connection and statement that will be used to create recordsets
  private Connection conn = null;
  private Statement stmt = null;
  private ResultSet rs = null;
  private int rowCount = 0;
  private int colCount = 0;
  private Properties props = new Properties();
  private Driver drv = null;
  // Get records from table and return in a 3D array
  public String[][] getTableRecords(String strSQL) {
    // Ensure that the variables used are set to 0 or null.  This will ensure
    // that there are no errors related to the results containing info from a
    // previous procedure call.
    rs = null;
    conn = null;
    stmt = null;
    rowCount = 0;
    colCount = 0;
    props = new Properties();
    drv = null;
    try {
      drv = (Driver) Class.forName("somedriver").newInstance();
    catch (Exception e) {
      System.out.println(e);
      return null;
    // Set properties for making a connection
    props.put("user", uname);
    props.put("password", pword);
    try {
      conn = drv.connect(url, props);
      stmt = conn.createStatement();
    catch (SQLException e) {
      System.out.println("SQL Error : " + e);
      return null;
    String[][] results = new String[0][0];
    // Execute SQL Query
    try {
      rs = stmt.executeQuery(strSQL);
      ResultSetMetaData rsmd = rs.getMetaData();
      // Get amount of columns.
      colCount = rsmd.getColumnCount();
      while (rs.next()) {
        rowCount++;
      // Remember to reset the resultset
      rs.close();
      rs = stmt.executeQuery(strSQL);
      if (rowCount < 1) {
        results = null;
      else {
        results = new String[rowCount][colCount];
        int currentRow = 0;
        while (rs.next()) {
          for (int i = 1; i <= colCount; i++) {
            String currentField = rs.getString(i);
            if (currentField == null) {
              currentField = "";
            // -1 is used to make sure that the rows/columns with an index of 0 are filled
            results[currentRow][i - 1] = currentField;
          currentRow++;
      // Close everything
      rs.close();
      stmt.close();
      conn.close();
    catch (Exception e) {
      results = null;
      System.out.println("SQL Error : "+ e);
    return results;
  // Execute some SQL that doesn't return a recordset
  public void execSQL(String action) {
    try {
      drv = (Driver) Class.forName("drivername").newInstance();
    catch (Exception e) {
      System.out.println(e);
    // Set properties for making a connection
    props = new Properties();
    props.put("user", uname);
    props.put("password", pword);
    try {
      conn = drv.connect(url, props);
      stmt = conn.createStatement();
      stmt.execute(action);
      // Close connection and statement
      stmt.close();
      conn.close();
    catch (SQLException e) {
      try {
        conn.close();
        stmt.close();
      catch (Exception f) {
      System.out.println("SQL Error : " + e);
  // Return the number of columns that are in the resultset
  public int getNoOfCols() {
    return colCount;
}

Answer 1

There are more than one possibilities out there. I want to describe two of it.
1) For rapid software development, you can use taglibs (Java Standard Tag Libraries or jakarta db taglibs) in your jsps. There are also other taglibs from different vendors, but I know only these two.
2) You can use JNDI to establish a database connection through a datasource object. This is the more often way in a production environment. There are also possibilities with pooling and so on.
It depends, on what you want to develop, for a simple page or prototyping, and low traffic, it is possible to use taglibs. For a complete web application, it is better to establish the connection through Datasources, which are handled by the JSP / Servlet container or the application server.
so long
ThK