Http 500 error when trying to logout with tomcat - java

I have a problem with the servlet that I'm making. You have to log into a system and you also need to log out, I use a file register the users. Login works fine, it reads the user from the file, but for some reason logout doesn't. I get an error when I press the logout-button:
Here is the code for the class LogoutServlet
package nl.hu.sp.lesson1.dynamicexample;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Scanner;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class LogoutServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
RequestDispatcher rd = null;
try {
String data = null;
File file = new File(
"C:/apache-tomcat-8.0.5/webapps/LoginAssignment/loggedusers.txt");
FileReader fr = new FileReader(file);
BufferedReader br = new BufferedReader(fr);
while ((data = br.readLine()) != null) {
String[] de = data.split(" ");
if (de[0].equals("vimal")) {
data.trim();
rd = req.getRequestDispatcher("testpage.html");
}
}
rd.forward(req, resp);
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}

You are reading a text file and searching for "vimal", if it is found you are initializing rd; if it is not found rd is null. It cannot find "vimal" in text file and rd becomes null so it throws null pointer exception.
Add null check
if (rd != null) {
rd.forward(req, resp);
}

Related

Sending XML message to JMS queue

am working with a project in which I am trying to call a Servlet that will push XML message to a JMS queue running in my local machine, using java code. You can find the actual Servlet code below, which actually sends the message to the queue.
import java.io.IOException;
import java.io.PrintWriter;
import javax.jms.JMSException;
import javax.jms.MessageProducer;
import javax.jms.ObjectMessage;
import javax.jms.Queue;
import javax.jms.QueueConnection;
import javax.jms.QueueConnectionFactory;
import javax.jms.QueueSender;
import javax.jms.QueueSession;
import javax.jms.TextMessage;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class MessageSender
extends HttpServlet
{
private static final long serialVersionUID = 1L;
static PrintWriter out;
public static final String CNN_FACTORY = "jms/alert/connectionFactory";
public static final String QUEUE_NAME = "jms/alert/amlScreenQueue";
public static String currentQueueName;
public static String JMSConnectionFactory;
private QueueConnection qcon;
private QueueSession qsession;
private static QueueSender qsender;
private Queue queue;
private static ObjectMessage om;
private static MessageProducer messageProducer;
public MessageSender() {}
public void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
try
{
String JMSQueueName = request.getParameter("JMSQueueName");
currentQueueName = JMSQueueName;
JMSConnectionFactory = request.getParameter("JMSConnectionFactory");
out = response.getWriter();
InitialContext ic = getInitialContext();
init(ic, JMSQueueName);
doPost(request, response);
}
catch (Exception e) {
e.printStackTrace();
}
}
public void init(Context ctx, String queueName)
throws NamingException, JMSException
{
QueueConnectionFactory qconFactory = (QueueConnectionFactory)ctx.lookup(JMSConnectionFactory);
this.qcon = qconFactory.createQueueConnection();
this.qsession = this.qcon.createQueueSession(false, 1);
queue = ((Queue)ctx.lookup(queueName));
QueueConnection qcon = qconFactory.createQueueConnection();
qcon.start();
QueueSession qsession = qcon.createQueueSession(false, 1);
qsender = qsession.createSender(queue);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
String textMessage = request.getParameter("textMessage");
try
{
TextMessage msg = qsession.createTextMessage(textMessage);
msg.setStringProperty("JMSXGroupID", "1");
msg.setIntProperty("JMSXGroupSeq", 1);
msg.setBooleanProperty("JMS_IBM_Last_Msg_In_Group", false);
qsender.send(msg);
out.println("Message sent to queue " + currentQueueName);
out.println("");
out.println(msg.getText());
}
catch (JMSException e)
{
e.printStackTrace();
out.println(e.getErrorCode());
try
{
qsender.close();
qcon.close();
}
catch (JMSException e) {
e.printStackTrace();
}
}
finally
{
try
{
qsender.close();
qcon.close();
}
catch (JMSException e) {
e.printStackTrace();
}
}
}
private static InitialContext getInitialContext() throws NamingException
{
return new InitialContext();
}
}
This is the java code that I am using to call the servlet,
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.URLConnection;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.List;
import java.util.Map.Entry;
public class SendMessage {
public static void main(String[] args) throws URISyntaxException{
String line;
StringBuffer buffer = new StringBuffer();
String data = null;
try
{
String filePath = "data/payload.xml";
File dataFile = new File(filePath);
if(dataFile.exists()){
data = new String(Files.readAllBytes(Paths.get(filePath)));
}else{
System.out.println("Not Available");
}
String localUrl = "http://localhost:8080/SimulationTool/MessageSender";
String params = "JMSQueueName=jms/alert/amlScreenQueue&"
+ "JMSConnectionFactory=jms/alert/connectionFactory&"
+ "textMessage=" + data;
System.out.println("PARAMS:::" + params);
URL url = new URL(localUrl);
System.out.println("URL FOUND:::" + url.toURI());
URLConnection conn = url.openConnection();
conn.setDoOutput(true);
conn.connect();
System.out.println("Response Code:::" + ((HttpURLConnection)conn).getResponseCode());
BufferedWriter out = new BufferedWriter( new OutputStreamWriter( conn.getOutputStream() ));
out.write(params);
out.flush();
out.close();
// Response code
System.out.println("Response Code:::" + ((HttpURLConnection)conn).getResponseCode());
// Response values
for (Entry<String, List<String>> header : ((HttpURLConnection)conn).getHeaderFields().entrySet()) {
System.out.println(header.getKey() + "=" + header.getValue());
}
BufferedReader in = new BufferedReader( new InputStreamReader( conn.getInputStream() ) );
String response;
while ( (response = in.readLine()) != null ) {
System.out.println( response );
}
in.close();
}
catch ( MalformedURLException ex ) {
ex.printStackTrace();
}
catch ( IOException ex ) {
ex.printStackTrace();
}
}
}
The problem is its failing with below exception,
Response Code:::200
java.net.ProtocolException: Cannot write output after reading input.
at sun.net.www.protocol.http.HttpURLConnection.getOutputStream0(HttpURLConnection.java:1312)
at sun.net.www.protocol.http.HttpURLConnection.getOutputStream(HttpURLConnection.java:1291)
at servlettests.SendMessage.main(SendMessage.java:63)
Its shows response code as 200, so the connection was successful but it fails while getting the outputstream, which is being created to send message to the queue. Pls help me on resolving this issue.

The constructor JSONObject(String) is undefined error - not able to resolve

I am trying to get some variables in servlet which are all passed through ajax call. But i am getting constructor JSONobject(string) is undefined error. I have imported required lib also. Please help
import com.google.gson.Gson;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.reflect.TypeToken;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;
import org.json.*;
public class insertserv extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
System.out.println("I am inside insert");
String json = "";
BufferedReader br = new BufferedReader(new InputStreamReader(request.getInputStream()));
if (br != null) {
json = br.readLine();
}
System.out.println(json);
JSONObject wholedata= new JSONObject(json);
response.setContentType("application/json");
PrintWriter out= response.getWriter();
}
}
removed org.json.simple.JSONObject; and updated with org.json.JSONObject; its solved my issue

Read HTTP POST from mobile in java

I have iOS Swift code, which sends a POST request to server. If i send this code directly to apple server i get response back with proper data. But when i send this to my server, server could not get the body of the HTTP POST.
I have no idea whether this issue is related to client side or server side.
Here is the Swift code.
func validateReceipt(completion : (status : Bool) -> ()) {
let receiptUrl = NSBundle.mainBundle().appStoreReceiptURL!
if NSFileManager.defaultManager().fileExistsAtPath(receiptUrl.path!)
{
if let receipt : NSData = NSData(contentsOfURL: receiptUrl)
{
let receiptdata: NSString = receipt.base64EncodedStringWithOptions(NSDataBase64EncodingOptions.EncodingEndLineWithLineFeed)
let dict = ["receipt-data" : receiptdata]
let jsonData = try! NSJSONSerialization.dataWithJSONObject(dict, options: NSJSONWritingOptions(rawValue: 0))
let request = NSMutableURLRequest(URL: NSURL(string: ReceiptURL.MAIN_SERVER.rawValue)!)
let session = NSURLSession.sharedSession()
request.HTTPMethod = "POST"
request.HTTPBody = jsonData
let task = session.dataTaskWithRequest(request, completionHandler: { data, response, error in
if let dataR = data
{
self.handleData(dataR, completion: { status in
completion(status: status)
})
}
})
task.resume()
}
else
{
completion(status: false)
}
}
else
{
completion(status: false)
}
}
and here is my Java code in server side, there are two Java classes which take care of this
MyRequestWrapper.Java
package webservice;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
public class MyRequestWrapper extends HttpServletRequestWrapper {
private final String body;
public MyRequestWrapper(HttpServletRequest request) throws IOException {
super(request);
StringBuilder stringBuilder = new StringBuilder();
BufferedReader bufferedReader = null;
try {
InputStream inputStream = request.getInputStream();
if (inputStream != null) {
bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
char[] charBuffer = new char[100000];
int bytesRead = -1;
while ((bytesRead = bufferedReader.read(charBuffer)) > 0) {
stringBuilder.append(charBuffer, 0, bytesRead);
}
} else {
stringBuilder.append("");
}
} catch (IOException ex) {
throw ex;
} finally {
if (bufferedReader != null) {
try {
bufferedReader.close();
} catch (IOException ex) {
throw ex;
}
}
}
body = stringBuilder.toString();
}
#Override
public ServletInputStream getInputStream() throws IOException {
final ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(body.getBytes());
ServletInputStream servletInputStream = new ServletInputStream() {
public int read() throws IOException {
return byteArrayInputStream.read();
}
};
return servletInputStream;
}
#Override
public BufferedReader getReader() throws IOException {
return new BufferedReader(new InputStreamReader(this.getInputStream()));
}
public String getBody() {
return this.body;
}
}
And here is the another class.
GetResult.Java
package webservice;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.ws.rs.Consumes;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import org.apache.log4j.Logger;
import org.json.JSONException;
import org.json.JSONObject;
#Path("/service")
public class GetResult {
static Logger logger = Logger.getLogger(GetResult.class);
// #Produces("application/json; charset=UTF-8")
//#Produces("text/plain")
#POST
#Produces (MediaType.APPLICATION_JSON)
public Response inapp(#Context HttpServletRequest request,
#Context HttpServletResponse response) throws Exception {
System.out.println("response===" + response);
System.out.println("Request-Header===" + request.getHeader("receipt-data"));
System.out.println("Request===" + request.getParameter("receipt-data"));
// System.out.println("Request==="+request.getReader());
// reader(request,response);
// getBody(request);
doFilter(request,response);
String result = "";
result = " " /* jsonObject */;
return Response.status(200).entity(result).build();
}
We could get the client IP and client Port from this request but unable to get the body. In production also we could not get the body. Some Java developers told me that you cant directly get the raw bytes in Java, i don't know about this.
Somebody please take a look at this, and tell me what i am doing wrong.
You may have to explicitly set the content type of the input post body you send to the server. This can be achieved as follows:
request.addValue("application/json", forHTTPHeaderField: "Content-Type")
Set the content type after setting the http method and son data to the request object( NSMutableURLRequest object)
This may help you!
Edited:
Actually the header field name is "Content-Type".

getting HTTP Status 404 - 502.shtml The requested resource is not available.while uploading a file

I'm getting the above error while using servlet I've written. the war file is set on Tomcat ver 7.0.39 installed on cPanel. the servlet compiled and tested on local machine no problem. I've learnet that there is a problem that has something to do with the cPanel/PHP config. I tried to play with the cPanel configuration but no luck
I feel that it has nothing to do with the java code but I'll put the fileUploadServlet anyhow
EDIT: I was able to upload a very small-sized file so it has something to do with file size \ long procssing time
package servlet;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.sql.SQLException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import javax.servlet.http.Part;
import convertor.TextAnalayzer;
import exception.ZoharException;
import beans.ParashaBean;
import beans.UserBean;
import jdbcHandler.JDBCZhoarHandler;
import util.ParashaName;
import util.XmlUrelParaser;
#WebServlet(urlPatterns = { "/upload" }, loadOnStartup = 1)
#MultipartConfig
public class FileUploadServlet extends HttpServlet {
private static final long serialVersionUID = 8626646959046203428L;
private JDBCZhoarHandler appHandler = new JDBCZhoarHandler();
public static final String ERROR_PARAMETER = "error";
public static final String COMMAND_PARAMETER = "command";
public static final String USER_ATTRIBUTE = "user";
public static final String HANDLER_ATTRIBUTE = "handler";
#Override
public void init() throws ServletException {
super.init();
try {
getServletConfig().getServletContext().setAttribute("list",
appHandler.viewParashot());
} catch (SQLException e) {
e.printStackTrace();
}
}
#Override
protected void service(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
String command = request.getParameter(COMMAND_PARAMETER);
String nextPage = "/login.jsp";
if ("convert".equals(command)) {
nextPage = this.upload(request, response);
} else if ("login".equals(command)) {
nextPage = this.login(request, response);
} else {
}// do nothing!!
this.getServletConfig().getServletContext()
.getRequestDispatcher(nextPage).forward(request, response);
}
private String login(HttpServletRequest request,
HttpServletResponse response) {
String name = request.getParameter("userName");
String password = request.getParameter("password");
JDBCZhoarHandler handler = new JDBCZhoarHandler();
try {
UserBean user = handler.getUser(name, password);
HttpSession session = request.getSession(true);
session.setAttribute(HANDLER_ATTRIBUTE, handler);
session.setAttribute(USER_ATTRIBUTE, user.getId());
return "/uploadFile.jsp";
} catch (Exception e) {
request.setAttribute(ERROR_PARAMETER, e.getMessage());
return "/login.jsp";
}
}
private String upload(HttpServletRequest request,
HttpServletResponse response) {
// view artifacts
HttpSession session = request.getSession(false);
ParashaName parashaName = new ParashaName();
JDBCZhoarHandler handler = (JDBCZhoarHandler) session
.getAttribute(HANDLER_ATTRIBUTE);
List<ParashaBean> list = null;
try {
list = handler.viewParashot();
} catch (SQLException e1) {
request.setAttribute(ERROR_PARAMETER, e1.getMessage());
}
session.setAttribute("list", list);
// Processing file
if ("convert".equals(request.getParameter("command"))) {
OutputStream out = null;
InputStream filecontent = null;
try {
// Create path components to save the file
XmlUrelParaser xml = new XmlUrelParaser();
SimpleDateFormat format = new SimpleDateFormat(
"dd-MM-yy_HH-mm-ss");
final Part filePart = request.getPart("file");
if (filePart.getSize() == 0) {
throw new ZoharException("you must upload a file first");
}
final String fileName = xml.getUR("incomingFilesDir")
+ session.getAttribute(USER_ATTRIBUTE)
+ parashaName.convert(Integer.parseInt(request
.getParameter("parasha")))
+ format.format(new Date()) + ".docx";
out = new FileOutputStream(new File(fileName));
filecontent = filePart.getInputStream();
int read = 0;
final byte[] bytes = new byte[1024];
while ((read = filecontent.read(bytes)) != -1) {
out.write(bytes, 0, read);
}
TextAnalayzer ta = new TextAnalayzer();
Integer ID = (Integer)session.getAttribute("user");
ta.analayze(fileName,
Integer.parseInt(request.getParameter("parasha")),
Boolean.parseBoolean(request.getParameter("orginal")),
ID);
request.setAttribute(ERROR_PARAMETER, "Upload complete");
return "/uploadFile.jsp";
} catch (Exception e) {
request.setAttribute(ERROR_PARAMETER, e.getMessage());
} finally {
try {
if (out != null) {
out.close();
}
if (filecontent != null) {
filecontent.close();
}
} catch (IOException e) {
request.setAttribute(ERROR_PARAMETER, e.getMessage());
}
}
}
return "/login.jsp";
}
}
This is a resault of memory lack. Better memory-managing code solved the problem.

fix the encoding in the servlets(java) [duplicate]

This question already has answers here:
How to get UTF-8 working in Java webapps?
(14 answers)
Closed 2 years ago.
Help fix the encoding in the servlet, it does not display Russian characters in the output.I will be very grateful for answers.
That is servlet code
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class servlet extends HttpServlet {
/**
*
*/
private static final long serialVersionUID = 1L;
public static List<String> getFileNames(File directory, String extension) {
List<String> list = new ArrayList<String>();
File[] total = directory.listFiles();
for (File file : total) {
if (file.getName().endsWith(extension)) {
list.add(file.getName());
}
if (file.isDirectory()) {
List<String> tempList = getFileNames(file, extension);
list.addAll(tempList);
}
}
return list;
}
#SuppressWarnings("resource")
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException{
request.setCharacterEncoding("utf8");
response.setContentType("text/html; charset=UTF-8");
String myName = request.getParameter("text");
List<String> files = getFileNames(new File("C:\\Users\\vany\\Desktop\\test"), "txt");
for (String string : files) {
if (myName.equals(string)) {
try {
File file = new File("C:\\Users\\vany\\Desktop\\test\\" + string);
FileReader reader = new FileReader(file);
int b;
PrintWriter writer = response.getWriter();
writer.print("<html>");
writer.print("<head>");
writer.print("<title>HelloWorld</title>");
writer.print("<body>");
writer.write("<div>");
while((b = reader.read()) != -1) {
writer.write((char) b);
}
writer.write("</div>");
writer.print("</body>");
writer.print("</html>");
}
catch (Exception ex) {
}
}
}
}
}
Here is what I have displayed instead of letters
 ршншнщ олрршшш ошгншщ шгшг ороргргр Это хрень работает ура
You're setting the character encoding on the request instead of the response. Change request.setCharacterEncoding("utf8"); to response.setCharacterEncoding("UTF-8");
Also: if the default character encoding of your system isn't UTF-8, you should explicitly set the encoding when reading from the file. To do that, you'd need to use an FileInputStream
pRes.setContentType("text/html; charset=UTF-8");
PrintWriter out = new PrintWriter(new OutputStreamWriter(pRes.getOutputStream(), "UTF8"), true);
use this one i got the exact result :)

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