<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<jsp:useBean id="db" class="beans.Datenbank" scope="session" />
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<%
try{
String wrong = request.getParameter("wrong");
if(wrong.equals("true")){
out.println("Username oder Passwort vergessen");
}
}
catch(Exception e){
System.out.println(e.getMessage());
}
if(!db.checkSession(session.getId())){ %>
<form action="login.jsp" method="post">
Name: <input type="text" name="username" maxlength="20"/><br>
Passwort: <input type="password" name="password" maxlength="20"/><br>
<input type="submit" value="Submit"/>
</form>
<% }
else{
response.sendRedirect("login.jsp");
} %>
</body>
</html><%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<jsp:useBean id="db" class="beans.Datenbank" scope="session" />
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<%
String username = request.getParameter("username");
String password = request.getParameter("password");
if(username == "" || password == ""){
response.sendRedirect("index.jsp?wrong=true");
}
else{
System.out.println(session.getId());
db.setSession(username,session.getId());
if(db.checkSession(session.getId()) || db.checkUser(username,password)){
%>
<a href="info.jsp">Info</a>
<br/><a href="logout.jsp">Ausloggen</a>
<% }
else{
response.sendRedirect("index.jsp");
}
}
%>
</body>
</html><%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<jsp:useBean id="db" class="beans.Datenbank" scope="session" />
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<%
if(db.checkSession(session.getId())){
out.println("jo bin eingeloggt super...");
%>
<a href="login.jsp">Login</a>
<%
}
else{
response.sendRedirect("index.jsp");
}
%>
</body>
</html><%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<jsp:useBean id="db" class="beans.Datenbank" scope="session" />
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<%
if(db.checkSession(session.getId())){
System.out.println("session zerstört");
session.invalidate();
db.unsetSession(session.getId());
response.sendRedirect("index.jsp");
}
else{
response.sendRedirect("index.jsp");
}
%>
</body>
</html>package beans;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import com.mysql.jdbc.PreparedStatement;
import com.mysql.jdbc.Statement;
public class Datenbank{
private Connection con;
private Connection startDb(){
try{
Class.forName("com.mysql.jdbc.Driver").newInstance();
con = DriverManager.getConnection("jdbc:mysql://localhost:3306/testlogin","root","test");
System.out.println("jdbc driver instantiated");
}
catch (Exception e){
System.err.println("cant instantiate jdbc Driver");
}
return con;
}
public void closeDb(){
try {
con.close();
System.out.println("Datenbank wurde geschlossen");
} catch (Exception e) {
System.err.println("Datenbank konnte nicht geschlossen werden");
}
}
public void setSession(String username,String sessionid){
Connection con = startDb();
try {
PreparedStatement pstmt = (PreparedStatement)con.prepareStatement("UPDATE user SET sessionid=? WHERE name=?");
pstmt.setString(1,sessionid);
pstmt.setString(2,username);
pstmt.executeUpdate();
} catch (SQLException e) {
e.printStackTrace();
System.err.println("Konnte Sessionid nicht setzen");
}
}
public void unsetSession(String sessionid){
Connection con = startDb();
try {
PreparedStatement pstmt = (PreparedStatement)con.prepareStatement("UPDATE user SET sessionid=? WHERE sessionid=?");
pstmt.setString(1,"");
pstmt.setString(2,sessionid);
pstmt.executeUpdate();
} catch (SQLException e) {
e.printStackTrace();
System.err.println("Konnte Sessionid nicht löschen");
}
}
public void createUser(String user, String password, String id){
Connection con = startDb();
try {
PreparedStatement pstmt = (PreparedStatement)con.prepareStatement("INSERT INTO user(name,password,sessionid) VALUES(?,?,?)");
pstmt.setString(1,user);
pstmt.setString(2,password);
pstmt.setString(3, id);
pstmt.executeUpdate();
} catch (SQLException e) {
e.printStackTrace();
System.err.println("Konnte User nicht erstellen");
}
}
public boolean checkSession(String sessionid){
Connection con = startDb();
PreparedStatement pstmt = null;
ResultSet rs;
boolean ok = false;
try {
pstmt = (PreparedStatement)con.prepareStatement("SELECT count(*) FROM user WHERE sessionid= ?");
pstmt.setString(1, sessionid);
rs = pstmt.executeQuery();
rs.next();
if(rs.getInt(1) > 0 && rs.getInt(1) < 2){
ok = true;
}
} catch (SQLException e) {
System.err.println("select session fehler");
e.printStackTrace();
}
return ok;
}
public boolean checkUser(String username, String password){
Connection con = startDb();
PreparedStatement pstmt = null;
ResultSet rs;
boolean ok = false;
try{
pstmt = (PreparedStatement)con.prepareStatement("SELECT count(*) FROM user WHERE name = ? AND password = ?");
pstmt.setString(1,username);
pstmt.setString(2,password);
rs = pstmt.executeQuery();
rs.next();
if(rs.getInt(1) > 0 && rs.getInt(1) < 2){
ok = true;
}
}
catch(SQLException e){
System.err.println("konnte user nicht finden");
e.printStackTrace();
}
return ok;
}
}
Ja.
Nö, die Vorgehensweise dafür lautet nicht Servlets oder JSP, sondern Servlets und JSP. Deswegen hab ich die JSTL erwähnt. Dann kommst du auch zu den Templates und all deine alten Probleme scheinen erst mal gelöst...
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<c:if test="${param.wrong == 'true'}"><c:out value="Username oder Password vergessen"/></c:if>
<c:choose>
<c:when test="${sessionScope[\"login\"] == null}">
<form action="LoginServ" method="post">
Name: <input type="text" name="username" maxlength="20"/><br>
Passwort: <input type="password" name="password" maxlength="20"/><br>
<input type="submit" value="Submit"/>
</form>
</c:when>
<c:otherwise><c:out value="Bereits angemeldet"/></c:otherwise>
</c:choose>
</body>
</html>package beans;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/**
* Servlet implementation class LoginServ
*/
public class LoginServ extends HttpServlet {
private static final long serialVersionUID = 1L;
private boolean login = true;
/**
* @see HttpServlet#HttpServlet()
*/
public LoginServ() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
handleResponse(request,response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
HttpSession session = request.getSession(true);
PrintWriter out = response.getWriter();
Datenbank db = Datenbank.getInstance();
String username = request.getParameter("username");
String password = request.getParameter("password");
if(username == "" || password == ""){
response.sendRedirect("index.jsp?wrong=true");
}
else{
session.setAttribute("login", login);
//db.setSession(username,session.getId());
if((Boolean)(session.getAttribute("login")) != null || db.checkUser(username,password)){
out.println("<a href=\"info.jsp\">Info</a>");
out.println("<br/><a href=\"LogoutServ\">Ausloggen</a>");
}
else{
response.sendRedirect("index.jsp");
}
}
}
protected void handleResponse(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
RequestDispatcher r = req.getRequestDispatcher("/index.jsp");
r.forward(req,resp);
}
}package beans;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/**
* Servlet implementation class LogoutServ
*/
public class LogoutServ extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public LogoutServ() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
HttpSession session = request.getSession(true);
if(session.getAttribute("login") != null){
System.out.println("session zerstört");
session.invalidate();
//db.unsetSession(session.getId());
response.sendRedirect("index.jsp");
}
else{
response.sendRedirect("index.jsp");
}
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request,response);
}
}package beans;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import com.mysql.jdbc.PreparedStatement;
public class Datenbank{
private Connection con;
private static Datenbank instance = null;
private Datenbank(){}
public static Datenbank getInstance(){
if(instance == null){
instance = new Datenbank();
}
return instance;
}
/**
* Startup Database
* @return Connection
*/
private Connection startDb(){
try{
Class.forName("com.mysql.jdbc.Driver").newInstance();
con = DriverManager.getConnection("jdbc:mysql://localhost:3306/testlogin","root","test");
System.out.println("jdbc driver instantiated");
}
catch (Exception e){
System.err.println("cant instantiate jdbc Driver");
}
return con;
}
/**
* close Database
*/
public void closeDb(){
try {
con.close();
System.out.println("Datenbank wurde geschlossen");
} catch (Exception e) {
System.err.println("Datenbank konnte nicht geschlossen werden");
}
}
/**
* set Session in in user Database, NOT IN USE RIGHT NOW
* @param username
* @param sessionid
*/
public void setSession(String username,String sessionid){
if(con == null){
con = startDb();
}
try {
PreparedStatement pstmt = (PreparedStatement)con.prepareStatement("UPDATE user SET sessionid=? WHERE name=?");
pstmt.setString(1,sessionid);
pstmt.setString(2,username);
pstmt.executeUpdate();
} catch (SQLException e) {
e.printStackTrace();
System.err.println("Konnte Sessionid nicht setzen");
}
}
/**
* unSet Session in in user Database, NOT IN USE RIGHT NOW
* @param sessionid
*/
public void unsetSession(String sessionid){
if(con == null){
con = startDb();
}
try {
PreparedStatement pstmt = (PreparedStatement)con.prepareStatement("UPDATE user SET sessionid=? WHERE sessionid=?");
pstmt.setString(1,"");
pstmt.setString(2,sessionid);
pstmt.executeUpdate();
} catch (SQLException e) {
e.printStackTrace();
System.err.println("Konnte Sessionid nicht löschen");
}
}
/**
* create user in user Database
* @param user
* @param password
* @param id
*/
public void createUser(String user, String password, String id){
if(con == null){
con = startDb();
}
try {
PreparedStatement pstmt = (PreparedStatement)con.prepareStatement("INSERT INTO user(name,password,sessionid) VALUES(?,?,?)");
pstmt.setString(1,user);
pstmt.setString(2,password);
pstmt.setString(3, id);
pstmt.executeUpdate();
} catch (SQLException e) {
e.printStackTrace();
System.err.println("Konnte User nicht erstellen");
}
}
/**
* checks if there is already a session with this sessionId, NOT IN USE RIGHT NOW
* @param sessionid
* @return
*/
public boolean checkSession(String sessionid){
if(con == null){
con = startDb();
}
PreparedStatement pstmt = null;
ResultSet rs;
boolean ok = false;
try {
pstmt = (PreparedStatement)con.prepareStatement("SELECT count(*) FROM user WHERE sessionid= ?");
pstmt.setString(1, sessionid);
rs = pstmt.executeQuery();
rs.next();
if(rs.getInt(1) > 0 && rs.getInt(1) < 2){
ok = true;
}
} catch (SQLException e) {
System.err.println("select session fehler");
e.printStackTrace();
}
return ok;
}
/**
* checks if user is registered
* @param username
* @param password
* @return
*/
public boolean checkUser(String username, String password){
if(con == null){
con = startDb();
}
PreparedStatement pstmt = null;
ResultSet rs;
boolean ok = false;
try{
pstmt = (PreparedStatement)con.prepareStatement("SELECT count(*) FROM user WHERE name = ? AND password = ?");
pstmt.setString(1,username);
pstmt.setString(2,password);
rs = pstmt.executeQuery();
rs.next();
if(rs.getInt(1) > 0 && rs.getInt(1) < 2){
ok = true;
}
}
catch(SQLException e){
System.err.println("konnte user nicht finden");
e.printStackTrace();
}
return ok;
}
}${param.wrong == 'true'} => ${param.wrong}
${sessionScope[\"login\"] == null} => ${!empty sessionScope[\"login\"]} if(username == "" || password == ""){
response.sendRedirect("index.jsp?wrong=true");
}response.sendRedirect("index.jsp?wrong=true");if((username.equals("") || password.equals("")) || !db.checkUser(username,password)){
session.setAttribute("wrong", true);
response.sendRedirect("index.jsp");
}
else{
session.setAttribute("login", login);
out.println("<a href=\"info.jsp\">Info</a>");
out.println("<br/><a href=\"LogoutServ\">Ausloggen</a>");
}username.equals("")Der Gedanke ist, dass kein Code aus dem View im Controller landet. Also lieber eine Variable setzen und diese mit JSLT auf true überprüfen, als HTML-Code in das Servlet zu schreiben. Ist bei dir jetzt nicht weiter schlimm, da du ja auf keine JSP weiterleiten tust, aber sobald das mal mehr wie zwei Zeilen werden bist schnell glücklich wenn eine JSP hast.
session.setAttribute("htmlcode", true);
RequestDispatcher rd = request.getRequestDispatcher("/auswahl.jsp");
rd.forward(request, response);
