This example shows you how the HTML and servlet classes work. It is a general overview. To view this example, compile and run it with a webserver and browser running.
import java.io.IOException;
import java.io.CharArrayWriter;
import java.io.PrintWriter;
import java.sql.*;
import java.util.Enumeration;
import java.util.Hashtable;
import javax.servlet.*;
import javax.servlet.http.*;
import com.ibm.as400.util.html.*;
import com.ibm.as400.util.servlet.*;
import com.ibm.as400.access.*;
/*
An example of using IBM Toolbox for Java classes in a servlet.
Schemas of SQL databases on the server:
File . . . . . . LICENSES
Library . . . LIGHTSON
Field Type Length Nulls
LICENSE CHARACTER 10 NOT NULL
USER_ID CHARACTER 10 NOT NULL WITH DEFAULT
E_MAIL CHARACTER 20 NOT NULL
WHEN_ADDED DATE NOT NULL WITH DEFAULT
TIME_STAMP TIMESTAMP NOT NULL WITH DEFAULT
File . . . . . . REPORTS
Library . . . LIGHTSON
Field Type Length Nulls
LICENSE CHARACTER 10 NOT NULL
REPORTER CHARACTER 10 NOT NULL WITH DEFAULT
DATE_ADDED DATE NOT NULL WITH DEFAULT
TIME_ADDED TIME NOT NULL WITH DEFAULT
TIME_STAMP TIMESTAMP NOT NULL WITH DEFAULT
LOCATION CHARACTER 10 NOT NULL
COLOR CHARACTER 10 NOT NULL
CATEGORY CHARACTER 10 NOT NULL
*/
public class LightsOn extends javax.servlet.http.HttpServlet
{
private AS400 system_;
private String password_; // password for the server and for the SQL database
private java.sql.Connection databaseConnection_;
public void destroy (ServletConfig config)
{
try {
if (databaseConnection_ != null) {
databaseConnection_.close();
}
}
catch (Exception e) { e.printStackTrace (); }
}
public void doGet (HttpServletRequest request,
HttpServletResponse response)
throws IOException, ServletException
{
HttpSession session = request.getSession();
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println(showHtmlMain());
out.close();
}
public void doPost (HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
HttpSession session = request.getSession(true);
ServletOutputStream out = response.getOutputStream();
response.setContentType("text/html");
Hashtable parameters = getRequestParameters (request);
if (parameters.containsKey("askingToReport"))
out.println (showHtmlForReporting ());
else if (parameters.containsKey("askingToRegister"))
out.println (showHtmlForRegistering ());
else if (parameters.containsKey("askingToUnregister"))
out.println(showHtmlForUnregistering());
else if (parameters.containsKey("askingToListRegistered"))
out.println (showHtmlForListingAllRegistered ());
else if (parameters.containsKey("askingToListReported"))
out.println (showHtmlForListingAllReported ());
else if (parameters.containsKey("returningToMain"))
out.println (showHtmlMain ());
else { // None of the above, so assume the user has filled out a form
// and is submitting information. Grab the incoming info
// and do the requested action.
if (parameters.containsKey("submittingReport")) {
String acknowledgement = reportLightsOn (parameters, out);
out.println (showAcknowledgement(acknowledgement));
}
else if (parameters.containsKey("submittingRegistration")) {
String acknowledgement = registerLicense (parameters, out);
out.println (showAcknowledgement(acknowledgement));
}
else if (parameters.containsKey("submittingUnregistration")) {
String acknowledgement = unregisterLicense (parameters, out);
out.println (showAcknowledgement(acknowledgement));
}
else {
out.println (showAcknowledgement("Error (internal): " +
"Neither Report, Register, " +
"Unregister, ListRegistered, or ListReported."));
}
}
out.close(); // Close the output stream.
}
// Gets the parameters from an HTTP servlet request, and packages them
// into a hashtable for convenience.
private static Hashtable getRequestParameters (HttpServletRequest request)
{
Hashtable parameters = new Hashtable ();
Enumeration enum = request.getParameterNames();
while (enum.hasMoreElements()) {
String key = (String) enum.nextElement();
String value = request.getParameter (key);
parameters.put (key, value);
}
return parameters;
}
// Removes blanks and hyphens from a String, and sets it to all uppercase.
private static String normalize (String oldString)
{
if (oldString == null || oldString.length() == 0) return null;
StringBuffer newString = new StringBuffer ();
for (int i=0; i<oldString.length(); i++) {
if (oldString.charAt(i) != ' ' && oldString.charAt(i) != '-')
newString.append (oldString.charAt(i));
}
return newString.toString().toUpperCase();
}
// Composes a list of single-quoted strings.
private static String quoteList (String[] inList)
{
StringBuffer outList = new StringBuffer();
for (int i=0; i<inList.length; i++)
{
outList.append ("'" + inList[i] + "'");
if (i<inList.length-1)
outList.append (",");
}
return outList.toString();
}
public String getServletInfo ()
{
return "Lights-On Servlet";
}
private AS400 getSystem ()
{
try
{
if (system_ == null)
{
system_ = new AS400();
// Note: It would be better to get these values
// from a properties file.
String sysName = "MYSYSTEM"; // TBD
String userId = "MYUSERID"; // TBD
String password = "MYPASSWD"; // TBD
system_.setSystemName(sysName);
system_.setUserId(userId);
system_.setPassword(password);
password_ = password;
system_.connectService(AS400.DATABASE);
system_.connectService(AS400.FILE);
system_.addPasswordCacheEntry(sysName, userId, password_);
}
}
catch (Exception e) { e.printStackTrace (); system_ = null; }
return system_;
}
public void init (ServletConfig config)
{
boolean rc;
try {
super.init(config);
// Register the JDBC driver.
try {
java.sql.DriverManager.registerDriver(new com.ibm.as400.access.AS400JDBCDriver());
}
catch (Exception e)
{
System.out.println("JDBC Driver not found");
}
}
catch (Exception e) { e.printStackTrace(); }
}
private void getDatabaseConnection ()
{
if (databaseConnection_ == null) {
try {
databaseConnection_ = java.sql.DriverManager.getConnection(
"jdbc:as400://" + getSystem().getSystemName() + "/" +
"LIGHTSON", getSystem().getUserId(), password_ );
}
catch (Exception e) { e.printStackTrace (); }
}
}
private String registerLicense (Hashtable parameters, ServletOutputStream out)
{
String licenseNum = normalize ((String)parameters.get("licenseNum"));
String eMailAddress = (String)parameters.get("eMailAddress");
StringBuffer acknowledgement = new StringBuffer();
if (licenseNum == null || licenseNum.length() == 0)
acknowledgement.append ("Error: License number not specified.\n");
if (eMailAddress == null || eMailAddress.length() == 0)
acknowledgement.append ("Error: Notification e-mail address not specified.\n");
if (acknowledgement.length() == 0)
{
try
{
// Insert the new license number and e-mail address into the database.
getDatabaseConnection ();
Statement sqlStatement = databaseConnection_.createStatement();
// Issue the request.
String cmd = "INSERT INTO LICENSES (LICENSE, E_MAIL) VALUES (" +
quoteList(new String[] {licenseNum, eMailAddress}) + ")";
sqlStatement.executeUpdate(cmd);
sqlStatement.close();
// Acknowledge the request.
acknowledgement.append ("License number " + licenseNum + " has been registered.");
acknowledgement.append ("Notification e-mail address is: " + eMailAddress);
}
catch (Exception e) { e.printStackTrace (); }
}
return acknowledgement.toString();
}
private String unregisterLicense (Hashtable parameters, ServletOutputStream out)
{
String licenseNum = normalize ((String)parameters.get("licenseNum"));
StringBuffer acknowledgement = new StringBuffer();
if (licenseNum == null || licenseNum.length() == 0)
acknowledgement.append ("Error: License number not specified.\n");
if (acknowledgement.length() == 0)
{
try
{
// Remove the specified license number and e-mail address from database.
getDatabaseConnection ();
Statement sqlStatement = databaseConnection_.createStatement();
// Delete the row(s) from the LICENSES database.
String cmd = "DELETE FROM LICENSES WHERE LICENSE = '" + licenseNum + "'";
sqlStatement.executeUpdate(cmd);
sqlStatement.close();
// Acknowledge the request.
acknowledgement.append ("License number " + licenseNum + " has been unregistered.");
}
catch (Exception e) { e.printStackTrace (); }
}
return acknowledgement.toString();
}
private String reportLightsOn (Hashtable parameters, ServletOutputStream out)
{
String licenseNum = normalize ((String)parameters.get("licenseNum"));
String location = (String)parameters.get("location");
String color = (String)parameters.get("color");
String category = (String)parameters.get("category");
StringBuffer acknowledgement = new StringBuffer();
if (licenseNum == null || licenseNum.length() == 0)
acknowledgement.append ("Error: License number not specified.");
if (acknowledgement.length() == 0)
{
try
{
// Report "lights on" for a specified vehicle.
getDatabaseConnection ();
Statement sqlStatement = databaseConnection_.createStatement();
// Add an entry to the REPORTS database.
String cmd = "INSERT INTO REPORTS (LICENSE, LOCATION, COLOR, CATEGORY) VALUES (" +
quoteList(new String[] {licenseNum, location, color, category}) + ")";
sqlStatement.executeUpdate(cmd);
sqlStatement.close();
// Acknowledge the request.
acknowledgement.append ("License number " + licenseNum + " has been reported. Thanks!");
}
catch (Exception e) { e.printStackTrace (); }
}
return acknowledgement.toString();
}
private String showHeader (String title)
{
StringBuffer page = new StringBuffer();
page.append("<html><head><title>" + title + "</title>");
page.append("</head><body bgcolor=\"blanchedalmond\">");
return page.toString ();
}
private String showAcknowledgement (String acknowledgement)
{
String title = "Acknowledgement";
StringBuffer page = new StringBuffer();
page.append (showHeader (title));
try {
HTMLForm form = new HTMLForm("LightsOn");
GridLayoutFormPanel grid = new GridLayoutFormPanel();
HTMLText text = new HTMLText(acknowledgement);
if (acknowledgement.startsWith("Error"))
text.setBold(true);
grid.addElement(text);
grid.addElement(new SubmitFormInput("returningToMain", "Home"));
form.addElement(grid);
page.append(form.toString());
}
catch (Exception e) { e.printStackTrace (); }
page.append("</body></html>");
return page.toString();
}
private String showHtmlMain ()
{
String title = "Lights-On tool";
StringBuffer page = new StringBuffer();
page.append (showHeader (title));
page.append("<h1>" + title + "</h1>");
// Create the HTML Form object.
HTMLForm mainForm = new HTMLForm("LightsOn");
GridLayoutFormPanel grid = new GridLayoutFormPanel();
try {
// Set up so that doPost() gets called when the form is submitted.
mainForm.setMethod(HTMLForm.METHOD_POST);
// Create some buttons.
grid.addElement(new SubmitFormInput("askingToReport", "Report a vehicle with lights on"));
grid.addElement(new SubmitFormInput("askingToRegister", "Register my license number"));
grid.addElement(new SubmitFormInput("askingToUnregister", "Unregister my license number"));
grid.addElement(new SubmitFormInput("askingToListRegistered", "List all registered licenses"));
grid.addElement(new SubmitFormInput("askingToListReported", "List all vehicles with lights on"));
mainForm.addElement(grid);
}
catch (Exception e) { e.printStackTrace (); }
page.append(mainForm.toString());
page.append("</body></html>");
return page.toString();
}
private String showHtmlForReporting ()
{
String title = "Report a vehicle with lights on";
StringBuffer page = new StringBuffer();
page.append (showHeader (title));
page.append("<h1>" + title + "</h1>");
// Create the HTML Form object.
HTMLForm reportForm = new HTMLForm("LightsOn");
GridLayoutFormPanel grid = new GridLayoutFormPanel(2);
try {
// Set up so that doPost() gets called when the form is submitted.
reportForm.setMethod(HTMLForm.METHOD_POST);
TextFormInput licenseNum = new TextFormInput("licenseNum");
licenseNum.setSize(10);
licenseNum.setMaxLength(10);
// Add elements to the line form
grid.addElement(new LabelFormElement("Vehicle license number:"));
grid.addElement(licenseNum);
// Create a radio button group and add the radio buttons.
RadioFormInputGroup colorGroup = new RadioFormInputGroup("color");
colorGroup.add("color", "white", "white", true);
colorGroup.add("color", "black", "black", false);
colorGroup.add("color", "gray", "gray", false);
colorGroup.add("color", "red", "red", false);
colorGroup.add("color", "yellow", "yellow", false);
colorGroup.add("color", "green", "green", false);
colorGroup.add("color", "blue", "blue", false);
colorGroup.add("color", "brown", "brown", false);
// Create a selection list for category of vehicle.
SelectFormElement category = new SelectFormElement("category");
category.addOption("sedan", "sedan", true);
category.addOption("convertible", "convertibl"); // 10-char field in DB
category.addOption("truck", "truck");
category.addOption("van", "van");
category.addOption("SUV", "SUV");
category.addOption("motorcycle", "motorcycle");
category.addOption("other", "other");
// Create a selection list for vehicle location (building number).
SelectFormElement location = new SelectFormElement("location");
location.addOption("001", "001", true);
location.addOption("002", "002");
location.addOption("003", "003");
location.addOption("005", "005");
location.addOption("006", "006");
location.addOption("015", "015");
grid.addElement(new LabelFormElement("Color:"));
grid.addElement(colorGroup);
grid.addElement(new LabelFormElement("Vehicle type:"));
grid.addElement(category);
grid.addElement(new LabelFormElement("Building:"));
grid.addElement(location);
grid.addElement(new SubmitFormInput("submittingReport", "Submit report"));
grid.addElement(new SubmitFormInput("returningToMain", "Home"));
reportForm.addElement(grid);
}
catch (Exception e) { e.printStackTrace (); }
page.append(reportForm.toString());
page.append("</body></html>");
return page.toString();
}
private String showHtmlForRegistering ()
{
String title = "Register my license number";
StringBuffer page = new StringBuffer();
page.append (showHeader (title));
page.append("<h1>" + title + "</h1>");
// Create the HTML Form object.
HTMLForm registrationForm = new HTMLForm("LightsOn");
// Set up a two-column panel layout, within which to arrange
// the generated HTML elements.
GridLayoutFormPanel grid = new GridLayoutFormPanel(2);
try {
// Set up so that doPost() gets called when the form is submitted.
registrationForm.setMethod(HTMLForm.METHOD_POST);
TextFormInput licenseNum = new TextFormInput("licenseNum");
licenseNum.setSize(10);
licenseNum.setMaxLength(10);
TextFormInput eMailAddress = new TextFormInput("eMailAddress");
eMailAddress.setMaxLength(20);
grid.addElement(new LabelFormElement("License number:"));
grid.addElement(licenseNum);
grid.addElement(new LabelFormElement("E-mail notification address:"));
grid.addElement(eMailAddress);
grid.addElement(new SubmitFormInput("submittingRegistration", "Register"));
grid.addElement(new SubmitFormInput("returningToMain", "Home"));
registrationForm.addElement(grid);
}
catch (Exception e) { e.printStackTrace (); }
page.append(registrationForm.toString());
page.append("</body></html>");
return page.toString();
}
private String showHtmlForUnregistering ()
{
String title = "Unregister my license number";
StringBuffer page = new StringBuffer();
page.append (showHeader (title));
page.append("<h1>" + title + "</h1>");
// Create the HTML Form object.
HTMLForm unregistrationForm = new HTMLForm("LightsOn");
GridLayoutFormPanel grid = new GridLayoutFormPanel(2);
try {
// Set up so that doPost() gets called when the form is submitted.
unregistrationForm.setMethod(HTMLForm.METHOD_POST);
// Create the LineLayoutFormPanel object.
TextFormInput licenseNum = new TextFormInput("licenseNum");
licenseNum.setSize(10);
licenseNum.setMaxLength(10);
grid.addElement(new LabelFormElement("Vehicle license number:"));
grid.addElement(licenseNum);
grid.addElement(new SubmitFormInput("submittingUnregistration", "Unregister"));
grid.addElement(new SubmitFormInput("returningToMain", "Home"));
unregistrationForm.addElement(grid);
}
catch (Exception e) {
e.printStackTrace ();
CharArrayWriter cWriter = new CharArrayWriter();
PrintWriter pWriter = new PrintWriter (cWriter, true);
e.printStackTrace (pWriter);
page.append (cWriter.toString());
}
page.append(unregistrationForm.toString());
page.append("</body></html>");
return page.toString();
}
private String showHtmlForListingAllRegistered ()
{
String title = "All registered licenses";
StringBuffer page = new StringBuffer();
page.append (showHeader (title));
try
{
// Create the HTML Form object.
HTMLForm mainForm = new HTMLForm("LightsOn");
// Set up a single-column panel layout, within which to arrange
// the generated HTML elements.
GridLayoutFormPanel grid = new GridLayoutFormPanel();
// Specify the layout for the generated table.
HTMLTable table = new HTMLTable();
table.setAlignment(HTMLConstants.LEFT);
table.setBorderWidth(3);
// Create and add the table caption and header.
HTMLTableCaption caption = new HTMLTableCaption();
caption.setAlignment(HTMLConstants.TOP);
caption.setElement(title);
table.setCaption(caption);
table.setHeader(new String[] { "License", "Date added" } );
// Create the converter, which will generate table HTML from
// the result set that comes back from the database query.
HTMLTableConverter converter = new HTMLTableConverter();
converter.setTable(table);
getDatabaseConnection ();
Statement sqlStatement = databaseConnection_.createStatement();
// First pre-query the database to verify that it's not empty.
String query = "SELECT COUNT(*) FROM LICENSES";
ResultSet rs = sqlStatement.executeQuery (query);
rs.next(); // position cursor to first row
int rowCount = rs.getInt(1);
if (rowCount == 0) {
page.append ("<font size=4 color=red>No vehicles have been reported.</font>");
}
else {
query = "SELECT LICENSE,WHEN_ADDED FROM LICENSES";
rs = sqlStatement.executeQuery (query);
SQLResultSetRowData rowData = new SQLResultSetRowData (rs);
HTMLTable[] generatedHtml = converter.convertToTables(rowData);
grid.addElement(generatedHtml[0]);
}
sqlStatement.close();
// Note: Mustn't close statement before we're done using result set.
grid.addElement(new SubmitFormInput("returningToMain", "Home"));
mainForm.addElement(grid);
page.append(mainForm.toString());
}
catch (Exception e) { e.printStackTrace (); }
page.append("</body></html>");
return page.toString();
}
private String showHtmlForListingAllReported ()
{
String title = "All vehicles with lights on";
StringBuffer page = new StringBuffer();
page.append (showHeader (title));
try
{
// Create the HTML Form object.
HTMLForm form = new HTMLForm("LightsOn");
// Set up a single-column panel layout, within which to arrange
// the generated HTML elements.
GridLayoutFormPanel grid = new GridLayoutFormPanel();
// Specify the layout for the generated table.
HTMLTable table = new HTMLTable();
table.setAlignment(HTMLConstants.LEFT);
table.setBorderWidth(3);
// Create and add the table caption and header.
HTMLTableCaption caption = new HTMLTableCaption();
caption.setAlignment(HTMLConstants.TOP);
caption.setElement(title);
table.setCaption(caption);
table.setHeader(new String[] { "License", "Color", "Category", "Date", "Time" } );
// Create the converter, which will generate table HTML from
// the result set that comes back from the database query.
HTMLTableConverter converter = new HTMLTableConverter();
converter.setTable(table);
getDatabaseConnection ();
Statement sqlStatement = databaseConnection_.createStatement();
// First pre-query the database to verify that it's not empty.
String query = "SELECT COUNT(*) FROM REPORTS";
ResultSet rs = sqlStatement.executeQuery (query);
rs.next(); // position cursor to first row
int rowCount = rs.getInt(1);
if (rowCount == 0) {
page.append ("<font size=4 color=red>No vehicles have been reported.</font>");
}
else {
query = "SELECT LICENSE,COLOR,CATEGORY,DATE_ADDED,TIME_ADDED FROM REPORTS";
rs = sqlStatement.executeQuery (query);
SQLResultSetRowData rowData = new SQLResultSetRowData (rs);
HTMLTable[] generatedHtml = converter.convertToTables(rowData);
grid.addElement(generatedHtml[0]);
}
sqlStatement.close();
// Note: Mustn't close statement before we're done using result set.
grid.addElement(new SubmitFormInput("returningToMain", "Home"));
form.addElement(grid);
page.append(form.toString());
}
catch (Exception e) { e.printStackTrace (); }
page.append("</body></html>");
return page.toString();
}
}