How to use

getParameter

method

in

javax.servlet.http.HttpServletRequest

 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  String username = request.getParameter("username");
  String password = request.getParameter("password");
  User user = userService.find(username, password);

  if (user != null) {
    request.getSession().setAttribute("user", user); // Login user.
    response.sendRedirect("home"); // Redirect to home page.
  } else {
    request.setAttribute("message", "Unknown username/password. Please retry."); // Store error message in request scope.
    request.getRequestDispatcher("/WEB-INF/login.jsp").forward(request, response); // Forward to JSP page to redisplay login form with error.
  }
}

 public class LoginAction implements Action {

  public String execute(HttpServletRequest request, HttpServletResponse response) throws Exception {
    String username = request.getParameter("username");
    String password = request.getParameter("password");
    User user = userDAO.find(username, password);

    if (user != null) {
      request.getSession().setAttribute("user", user); // Login user.
      return "home"; // Redirect to home page.
    }
    else {
      request.setAttribute("error", "Unknown username/password. Please retry."); // Store error message in request scope.
      return "login"; // Go back to redisplay login form with error.
    }
  }

}

 @WebServlet("/product")
public class ProductServlet extends HttpServlet {

  @EJB
  private ProductService productService;

  @Override
  protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    Product product = productService.find(request.getParameter("id"));
    request.setAttribute("product", product); // Will be available as ${product} in JSP
    request.getRequestDispatcher("/WEB-INF/product.jsp").forward(request, response);
  }

}

@Override
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, java.io.IOException {
  String id = request.getParameter("id");
  PrintWriter out = response.getWriter();
  response.setContentType("text/plain");
  out.println("Id is " + id);
}

 @Override
 public synchronized void execute(final HttpServletRequest request,
   final HttpServletResponse response) throws IOException {
  String prefix = request.getParameter("prefix");
  prefix = (prefix == null ? "" : prefix);
  List<String> values = eventHub.getEventValues(
    request.getParameter("event_type"),
    request.getParameter("event_key"),
    prefix);
  response.getWriter().println(gson.toJson(values));
 }
}

private Long lookupSandboxId(HttpServletRequest request) {
  String sandboxIdStr = request.getParameter(SANDBOX_ID_VAR);
  Long sandboxId = null;
  if (sandboxIdStr != null) {
    try {
      sandboxId = Long.valueOf(sandboxIdStr);
      if (LOG.isTraceEnabled()) {
        LOG.trace("SandboxId found on request " + sandboxId);
      }
    } catch (NumberFormatException nfe) {
      LOG.warn("blcSandboxId parameter could not be converted into a Long", nfe);
    }
  }
  if (sandboxId == null) {
    // check the session
    HttpSession session = request.getSession(false);
    if (session != null) {
      sandboxId = (Long) session.getAttribute(SANDBOX_ID_VAR);
      if (LOG.isTraceEnabled()) {
        if (sandboxId != null) {
          LOG.trace("SandboxId found in session " + sandboxId);
        }
      }
    }
  } else {
    HttpSession session = request.getSession();
    session.setAttribute(SANDBOX_ID_VAR, sandboxId);
  }
  return sandboxId;
}

public void render(HttpServletRequest req, HttpServletResponse resp, Object obj)
    throws IOException {
  if (resp.getContentType() == null)
    if (jsonp)
      resp.setContentType(JSONP_CT);
    else
      resp.setContentType(CT);
  Writer writer = resp.getWriter();
  if (jsonp)
    writer.write(req.getParameter(jsonpParam == null ? "callback" : jsonpParam) + "(");
  Mvcs.write(resp, writer, null == obj ? data : obj, format);
  if (jsonp)
    writer.write(");");
}

String usernameParam = request.getParameter(PARAM_NAME_USERNAME);
String passwordParam = request.getParameter(PARAM_NAME_PASSWORD);
if (username.equals(usernameParam) && password.equals(passwordParam)) {
  request.getSession().setAttribute(SESSION_USER_KEY, username);
  response.getWriter().print("success");
} else {
  response.getWriter().print("error");
|| path.startsWith("/img"))) {
if (contextPath.equals("") || contextPath.equals("/")) {
  response.sendRedirect("/druid/login.html");
} else {
  if ("".equals(path)) {
    response.sendRedirect("druid/login.html");
  } else {
    response.sendRedirect("login.html");
  fullUrl += "?" + request.getQueryString();
response.getWriter().print(process(fullUrl));
return;

/**
 * {@inheritDoc}
 */
@Override
protected void doPost( final HttpServletRequest request, final HttpServletResponse response ) throws ServletException, IOException {
  LOG.info( "invoked" );
  final HttpSession session = request.getSession();
  waitIfRequested( request );
  final PrintWriter out = response.getWriter();
  out.println( "OK: " + session.getId() );
  @SuppressWarnings( "unchecked" )
  final Enumeration<String> names = request.getParameterNames();
  while ( names.hasMoreElements() ) {
    final String name = names.nextElement();
    final String value = request.getParameter( name );
    session.setAttribute( name, value );
  }
}

  @Override
  protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    logger.debug("Export Get Action!");
    try {
      Properties globalProps = (Properties) this.getServletContext().getAttribute("globalProps");
      String zkServer = globalProps.getProperty("zkServer");
      String[] zkServerLst = zkServer.split(",");

      String authRole = (String) request.getSession().getAttribute("authRole");
      if (authRole == null) {
        authRole = ZooKeeperUtil.ROLE_USER;
      }
      String zkPath = request.getParameter("zkPath");
      StringBuilder output = new StringBuilder();
      output.append("#App Config Dashboard (ACD) dump created on :").append(new Date()).append("\n");
      Set<LeafBean> leaves = ZooKeeperUtil.INSTANCE.exportTree(zkPath, ServletUtil.INSTANCE.getZookeeper(request, response, zkServerLst[0], globalProps), authRole);
      for (LeafBean leaf : leaves) {
        output.append(leaf.getPath()).append('=').append(leaf.getName()).append('=').append(ServletUtil.INSTANCE.externalizeNodeValue(leaf.getValue())).append('\n');
      }// for all leaves
      response.setContentType("text/plain;charset=UTF-8");
      try (PrintWriter out = response.getWriter()) {
        out.write(output.toString());
      }

    } catch (InterruptedException | KeeperException ex) {
      logger.error(Arrays.toString(ex.getStackTrace()));
      ServletUtil.INSTANCE.renderError(request, response, ex.getMessage());
    }
  }
}

@Override
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  request.setAttribute("jaccTest", "true");
  try {
    HttpServletRequest requestFromPolicy = (HttpServletRequest) PolicyContext.getContext("javax.servlet.http.HttpServletRequest");
    if (requestFromPolicy != null) {
      response.getWriter().print("Obtained request from context.");
      if ("true".equals(requestFromPolicy.getAttribute("jaccTest"))) {
        response.getWriter().print("Attribute present in request from context.");
      }
      if ("true".equals(requestFromPolicy.getParameter("jacc_test"))) {
        response.getWriter().print("Request parameter present in request from context.");
      }
    }
  } catch (PolicyContextException e) {
    e.printStackTrace(response.getWriter());
  }
}

  public boolean verify(HttpServletRequest request) {
    String postedToken = request.getParameter(TOKEN);
    String expectedToken = (String) request.getSession().getAttribute(TOKEN);
    return !StringUtils.isBlank(postedToken) && !StringUtils.isBlank(expectedToken) && postedToken.equals(expectedToken);
  }
}

 @Override
 protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException {
  String peepText = req.getParameter("peep");

  try {

   PeeperServletContextListener.DATA_STORE.addPeep(peepText);
   resp.sendRedirect("peep");

  } catch (Exception e) {
   throw new ServletException("Error saving peep", e);
  }
 }
}

private void addResults(HttpServletRequest request,
            HttpServletResponse response) throws IOException {
 String input = request.getParameter("input");
 if (input == null) {
  return;
 PrintWriter out = response.getWriter();
 if (input.length() > MAXIMUM_QUERY_LENGTH) {
  out.print("This query is too long.  If you want to run very long queries, please download and use our <a href=\"http://nlp.stanford.edu/software/CRF-NER.html\">publicly released distribution</a>.");
  return;
 String outputFormat = request.getParameter("outputFormat");
 if (outputFormat == null || outputFormat.trim().isEmpty()) {
  outputFormat = this.format;
 String preserveSpacingStr = request.getParameter("preserveSpacing");
 if (preserveSpacingStr == null || preserveSpacingStr.trim().isEmpty()) {
  preserveSpacing = this.spacing;
 String classifier = request.getParameter("classifier");
 if (classifier == null || classifier.trim().isEmpty()) {
  classifier = this.defaultClassifier;
  outputHighlighting(out, ners.get(classifier), input);
 } else {
  out.print(StringEscapeUtils.escapeHtml4(ners.get(classifier).classifyToString(input, outputFormat, preserveSpacing)));

String action = request.getParameter("action");
String currentPath = request.getParameter("currentPath");
String displayPath = request.getParameter("displayPath");
String newProperty = request.getParameter("newProperty");
String newValue = request.getParameter("newValue");
String newNode = request.getParameter("newNode");
String searchStr = request.getParameter("searchStr").trim();
String authRole = (String) request.getSession().getAttribute("authRole");
      request.getSession().setAttribute("flashMsg", "Node created!");
      dao.insertHistory((String) request.getSession().getAttribute("authName"), request.getRemoteAddr(), "Creating node: " + currentPath + newNode);
    response.sendRedirect("/home?zkPath=" + displayPath);
    break;
  case "Save Property":
      request.getSession().setAttribute("flashMsg", "Property Saved!");
      if (ZooKeeperUtil.INSTANCE.checkIfPwdField(newProperty)) {
        newValue = ZooKeeperUtil.INSTANCE.SOPA_PIPA;
      dao.insertHistory((String) request.getSession().getAttribute("authName"), request.getRemoteAddr(), "Saving Property: " + currentPath + "," + newProperty + "=" + newValue);
    response.sendRedirect("/home?zkPath=" + displayPath);
    break;
  case "Update Property":
      dao.insertHistory((String) request.getSession().getAttribute("authName"), request.getRemoteAddr(), "Updating Property: " + currentPath + "," + newProperty + "=" + newValue);

 @Override
 public void doGet(HttpServletRequest request,
          HttpServletResponse response
          ) throws ServletException, IOException {
  PrintWriter out = response.getWriter();
  SortedSet<String> sortedKeys = new TreeSet<>();
  Enumeration<String> keys = request.getParameterNames();
  while(keys.hasMoreElements()) {
   sortedKeys.add(keys.nextElement());
  }
  for(String key: sortedKeys) {
   out.print(key);
   out.print(':');
   out.print(request.getParameter(key));
   out.print('\n');
  }
  out.close();
 }
}

/**
 * @see org.acegisecurity.ui.AbstractProcessingFilter#determineFailureUrl(javax.servlet.http.HttpServletRequest, org.acegisecurity.AuthenticationException)
 */
@Override
protected String determineFailureUrl(HttpServletRequest request, AuthenticationException failed) {
  Properties excMap = getExceptionMappings();
  String failedClassName = failed.getClass().getName();
  String whereFrom = request.getParameter("from");
  request.getSession().setAttribute("from", whereFrom);
  return excMap.getProperty(failedClassName, getAuthenticationFailureUrl());
}

@Override
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  response.getWriter().write("Public resource invoked\n");
  if (request.getParameter("doLogout") != null) {
    request.logout();
  }
}

String file = req.getPathInfo();
if (file == null) {
  resp.sendRedirect(req.getRequestURI() + "/");
  return;
} else if (file.startsWith("/")) {
while (en.hasMoreElements()) {
  String name = en.nextElement().toString();
  String value = req.getParameter(name);
  attributes.put(name, value);
    bytes = page.getBytes(StandardCharsets.UTF_8);
  resp.setContentType(mimeType);
  if (!cache) {
    resp.setHeader("Cache-Control", "no-cache");

/**
 * Checks if {@link jodd.servlet.tag.CsrfTokenTag CSRF token} is valid.
 * Returns <code>false</code> if token was requested, but not found.
 * Otherwise, it returns <code>true</code>.
 */
@SuppressWarnings({"unchecked"})
public static boolean checkCsrfToken(final HttpServletRequest request, final String tokenName) {
  String tokenValue = request.getParameter(tokenName);
  return checkCsrfToken(request.getSession(), tokenValue);
}