Membuat Servlet Filter dan Servlet Listener Part 1
Hallo, lama tak berjumpa. postingan kali ini saya masih akan mengulas yang berhubungan dengan servlet.
oke, langsung aja kita akan membuat :
1. Servlet Filter Login
buat project baru di netbean kamu dengan memlih web application, beri nama nama filterlogin. setelah buat project baru, buka file index.html lalu masukkan kode berikut :
<!DOCTYPE html>
<html>
<head>
<title></title>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
</head>
<body>
<form action="LoginServlet" method="post">
Username: <input type="text" name="user">
<br>
Password: <input type="password" name="pwd">
<br>
<input type="submit" value="Login">
</form>
</body>
</html>
kemudian buat file servlet baru dengan nama LoginServlet.java
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/**
*
* @author fitri
*/
public class LoginServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
private final String userID = "admin";
private final String password = "123";
/**
* Processes requests for both HTTP
* <code>GET</code> and
* <code>POST</code> methods.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
try {
/* TODO output your page here. You may use following sample code. */
out.println("<html>");
out.println("<head>");
out.println("<title>Servlet LoginServlet</title>");
out.println("</head>");
out.println("<body>");
out.println("<h1>Servlet LoginServlet at " + request.getContextPath() + "</h1>");
out.println("</body>");
out.println("</html>");
} finally {
out.close();
}
}
// <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
/**
* Handles the HTTP
* <code>GET</code> method.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
/**
* Handles the HTTP
* <code>POST</code> method.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// processRequest(request, response);
String user = request.getParameter("user");
String pwd = request.getParameter("pwd");
if (userID.equals(user) && password.equals(pwd)) {
HttpSession session = request.getSession();
session.setAttribute("user", "Pankaj");
//setting session to expiry in 30 mins 88
session.setMaxInactiveInterval(30 * 60);
Cookie userName = new Cookie("user", user);
userName.setMaxAge(30 * 60);
response.addCookie(userName);
response.sendRedirect("LoginSuccess.jsp");
} else {
RequestDispatcher rd = getServletContext().getRequestDispatcher("/index.html");
PrintWriter out = response.getWriter();
out.println("<font color=red>Either user name or password is wrong.</font>");
rd.include(request, response);
}
}
/**
* Returns a short description of the servlet.
*
* @return a String containing servlet description
*/
@Override
public String getServletInfo() {
return "Short description";
}// </editor-fold>
}
setelah membuat servlet untuk login, kita akan membuat servlet untuk logout dengan nama file LogoutServlet.java. berikut kodenya :
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/**
*
* @author fitri
*/
public class LogoutServlet extends HttpServlet {
/**
* Processes requests for both HTTP
* <code>GET</code> and
* <code>POST</code> methods.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
try {
/* TODO output your page here. You may use following sample code. */
out.println("<html>");
out.println("<head>");
out.println("<title>Servlet LogoutServlet</title>");
out.println("</head>");
out.println("<body>");
out.println("<h1>Servlet LogoutServlet at " + request.getContextPath() + "</h1>");
out.println("</body>");
out.println("</html>");
} finally {
out.close();
}
}
// <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
/**
* Handles the HTTP
* <code>GET</code> method.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
/**
* Handles the HTTP
* <code>POST</code> method.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
Cookie[] cookies = request.getCookies();
if (cookies != null) {
for (Cookie cookie : cookies) {
if (cookie.getName().equals("JSESSIONID")) {
System.out.println("JSESSIONID=" + cookie.getValue());
break;
}
}
}
//invalidate the session if exists
HttpSession session = request.getSession(false);
System.out.println("User=" + session.getAttribute("user"));
if (session != null) {
session.invalidate();
}
response.sendRedirect("index.html");
}
/**
* Returns a short description of the servlet.
*
* @return a String containing servlet description
*/
@Override
public String getServletInfo() {
return "Short description";
}// </editor-fold>
}
lanjutkan dengan buat file RequestLoggingFilter.java
import java.io.IOException;
import java.io.PrintStream;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.util.Enumeration;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
/**
*
* @author fitri
*/
public class RequestLoggingFilter implements Filter {
private static final boolean debug = true;
// The filter configuration object we are associated with. If
// this value is null, this filter instance is not currently
// configured.
private FilterConfig filterConfig = null;
//private ServletContext context;
public RequestLoggingFilter() {
}
private void doBeforeProcessing(ServletRequest request, ServletResponse response)
throws IOException, ServletException {
if (debug) {
log("RequestLoggingFilter:DoBeforeProcessing");
}
HttpServletRequest req = (HttpServletRequest) request;
Enumeration params = req.getParameterNames();
while (params.hasMoreElements()) {
String name = params.nextElement();
String value = request.getParameter(name);
log(req.getRemoteAddr() + "::Request Params::{" + name + "=" + value + "}");
}
Cookie[] cookies = req.getCookies();
if (cookies != null) {
for (Cookie cookie : cookies) {
log(req.getRemoteAddr() + "::Cookie::{" + cookie.getName() + "," + cookie.getValue() + "}");
}
}
}
private void doAfterProcessing(ServletRequest request, ServletResponse response)
throws IOException, ServletException {
if (debug) {
log("RequestLoggingFilter:DoAfterProcessing");
}
}
/**
*
* @param request The servlet request we are processing
* @param response The servlet response we are creating
* @param chain The filter chain we are processing
*
* @exception IOException if an input/output error occurs
* @exception ServletException if a servlet error occurs
*/
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
if (debug) {
log("RequestLoggingFilter:doFilter()");
}
doBeforeProcessing(request, response);
Throwable problem = null;
try {
chain.doFilter(request, response);
} catch (Throwable t) {
// If an exception is thrown somewhere down the filter chain,
// we still want to execute our after processing, and then
// rethrow the problem after that.
problem = t;
t.printStackTrace();
}
doAfterProcessing(request, response);
// If there was a problem, we want to rethrow it if it is
// a known type, otherwise log it.
if (problem != null) {
if (problem instanceof ServletException) {
throw (ServletException) problem;
}
if (problem instanceof IOException) {
throw (IOException) problem;
}
sendProcessingError(problem, response);
}
}
/**
* Return the filter configuration object for this filter.
*/
public FilterConfig getFilterConfig() {
return (this.filterConfig);
}
/**
* Set the filter configuration object for this filter.
*
* @param filterConfig The filter configuration object
*/
public void setFilterConfig(FilterConfig filterConfig) {
this.filterConfig = filterConfig;
}
/**
* Destroy method for this filter
*/
public void destroy() {
}
/**
* Init method for this filter
*/
public void init(FilterConfig filterConfig) {
this.filterConfig = filterConfig;
if (filterConfig != null) {
if (debug) {
log("RequestLoggingFilter:Initializing filter");
}
}
}
/**
* Return a String representation of this object.
*/
@Override
public String toString() {
if (filterConfig == null) {
return ("RequestLoggingFilter()");
}
StringBuffer sb = new StringBuffer("RequestLoggingFilter(");
sb.append(filterConfig);
sb.append(")");
return (sb.toString());
}
private void sendProcessingError(Throwable t, ServletResponse response) {
String stackTrace = getStackTrace(t);
if (stackTrace != null && !stackTrace.equals("")) {
try {
response.setContentType("text/html");
PrintStream ps = new PrintStream(response.getOutputStream());
PrintWriter pw = new PrintWriter(ps);
pw.print("\n\nError \n\n\n");
// PENDING! Localize this for next official release
pw.print("The resource did not process correctly
\n\n");
pw.print(stackTrace);
pw.print("\n"); //NOI18N
pw.close();
ps.close();
response.getOutputStream().close();
} catch (Exception ex) {
}
} else {
try {
PrintStream ps = new PrintStream(response.getOutputStream());
t.printStackTrace(ps);
ps.close();
response.getOutputStream().close();
} catch (Exception ex) {
}
}
}
public static String getStackTrace(Throwable t) {
String stackTrace = null;
try {
StringWriter sw = new StringWriter();
PrintWriter pw = new PrintWriter(sw);
t.printStackTrace(pw);
pw.close();
sw.close();
stackTrace = sw.getBuffer().toString();
} catch (Exception ex) {
}
return stackTrace;
}
public void log(String msg) {
filterConfig.getServletContext().log(msg);
}
}
selanjutnya buat file servlet AuthenticationFilter.java
import java.io.IOException;
import java.io.PrintStream;
import java.io.PrintWriter;
import java.io.StringWriter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/**
*
* @author fitri
*/
public class AuthenticationFilter extends HttpServlet {
private static final boolean debug = true;
// The filter configuration object we are associated with. If
// this value is null, this filter instance is not currently
// configured.
private FilterConfig filterConfig = null;
public AuthenticationFilter() {
}
private void doBeforeProcessing(ServletRequest request, ServletResponse response)
throws IOException, ServletException {
if (debug) {
log("AuthenticationFilter:DoBeforeProcessing");
}
}
private void doAfterProcessing(ServletRequest request, ServletResponse response)
throws IOException, ServletException {
if (debug) {
log("AuthenticationFilter:DoAfterProcessing");
}
}
/**
* Processes requests for both HTTP GET and POST
* methods.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain)
throws IOException, ServletException {
if (debug) {
log("AuthenticationFilter:doFilter()");
}
doBeforeProcessing(request, response);
Throwable problem = null;
try {
HttpServletRequest req = (HttpServletRequest) request;
HttpServletResponse res = (HttpServletResponse) response;
String uri = req.getRequestURI();
log("Requested Resource::" + uri);
HttpSession session = req.getSession(false);
if (session == null && !(uri.endsWith("html") || uri.endsWith("LoginServlet"))) {
log("Unauthorized access request");
res.sendRedirect("index.html");
}else{
// pass the request along the filter chain
chain.doFilter(request, response);
}
} catch (Throwable t) {
// If an exception is thrown somewhere down the filter chain,
// we still want to execute our after processing, and then
// rethrow the problem after that.
problem = t;
t.printStackTrace();
}
doAfterProcessing(request, response);
// If there was a problem, we want to rethrow it if it is
// a known type, otherwise log it.
if (problem != null) {
if (problem instanceof ServletException) {
throw (ServletException) problem;
}
if (problem instanceof IOException) {
throw (IOException) problem;
}
sendProcessingError(problem, response);
}
}
/**
* Return the filter configuration object for this filter.
*/
public FilterConfig getFilterConfig() {
return (this.filterConfig);
}
/**
* Set the filter configuration object for this filter.
*
* @param filterConfig The filter configuration object
*/
public void setFilterConfig(FilterConfig filterConfig) {
this.filterConfig = filterConfig;
}
/**
* Destroy method for this filter
*/
public void destroy() {
}
/**
* Init method for this filter
*/
public void init(FilterConfig filterConfig) {
this.filterConfig = filterConfig;
if (filterConfig != null) {
if (debug) {
log("AuthenticationFilter:Initializing filter");
}
}
}
/**
* Return a String representation of this object.
*/
@Override
public String toString() {
if (filterConfig == null) {
return ("AuthenticationFilter()");
}
StringBuffer sb = new StringBuffer("AuthenticationFilter(");
sb.append(filterConfig);
sb.append(")");
return (sb.toString());
}
private void sendProcessingError(Throwable t, ServletResponse response) {
String stackTrace = getStackTrace(t);
if (stackTrace != null && !stackTrace.equals("")) {
try {
response.setContentType("text/html");
PrintStream ps = new PrintStream(response.getOutputStream());
PrintWriter pw = new PrintWriter(ps);
pw.print("\n\nError \n\n\n");
//NOI18N
// PENDING! Localize this for next official release
pw.print("The resource did not process correctly
\n\n");
pw.print(stackTrace);
pw.print("\n");
//NOI18N
pw.close();
ps.close();
response.getOutputStream().close();
} catch (Exception ex) {
}
} else {
try {
PrintStream ps = new PrintStream(response.getOutputStream());
t.printStackTrace(ps);
ps.close();
response.getOutputStream().close();
} catch (Exception ex) {
}
}
}
public static String getStackTrace(Throwable t) {
String stackTrace = null;
try {
StringWriter sw = new StringWriter();
PrintWriter pw = new PrintWriter(sw);
t.printStackTrace(pw);
pw.close();
sw.close();
stackTrace = sw.getBuffer().toString();
} catch (Exception ex) {
}
return stackTrace;
}
public void log(String msg) {
filterConfig.getServletContext().log(msg);
}
}
semua kode sudah selesai, langkah terakhir ubah di file web.xml menjadi seperti di bawah ini
Setelah selesai semua, jalankan aplikasi Anda. Selamat Bereksplorasi :) tunggu di part 2 ya .. Wassalamualaikum wr. wbRequestLoggingFilter RequestLoggingFilter AuthenticationFilter AuthenticationFilter RequestLoggingFilter /* REQUEST AuthenticationFilter /* LoginServlet LoginServlet LogoutServlet LogoutServlet LoginServlet /LoginServlet LogoutServlet /LogoutServlet 30
