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I am getting a Java EE HTTP Status 500 - Permission Denied, when running my local project in a browser. But it can correctly read and write from the file with the same code when running it in Netbeans through a main method.

I have tried to look answers up on SO, and I have not found a solution specific enough.

My index.jsp:

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>JSP Page</title>
    </head>
    <body>
        <form action="Servlet" method="post">
            <input type="text" name="userInput">
            <input type="submit" name="Servlet">           
        </form>        
    </body>
</html>

Servlet.java:

@WebServlet("/Servlet")
public class Servlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setAttribute("lol", "lol");
        req.getRequestDispatcher("index.jsp").forward(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        if (req.getParameter("userInput") != null) {
            System.out.println("gotcha");
            IO io = new IO(req.getParameter("userInput"));
            //req.setAttribute("input", io.readFile());
            //System.out.println(io.readFile());
        }
        req.getRequestDispatcher("tab.jsp").forward(req, resp);
    }

}

IO.java:

public class IO {

    final String FILENAME = "file.txt";

    public static void main(String[] args) throws IOException {
        FileWriter fw = new FileWriter("file.txt", true);
        PrintWriter pw = new PrintWriter(fw);
        pw.println("test");
        pw.flush();
    }

    public IO() throws FileNotFoundException {
    }

    public IO(String text) throws IOException {
        FileWriter fw = new FileWriter(FILENAME, true);
        PrintWriter pw = new PrintWriter(fw);
        pw.println(text + ",");
        pw.flush();
    }

    public String readFile() throws IOException {
        StringBuilder sb = new StringBuilder();
        FileReader fr = new FileReader(FILENAME);
        int data = fr.read();
        while (data != -1) {
            sb.append(fr.read());
            data = fr.read();
        }
        return sb.toString();
    }
}

It chrashes in the constructor on the following line

FileWriter fw = new FileWriter(FILENAME, true);

Full stacktrace 

19-Aug-2018 20:10:29.265 SEVERE [http-nio-8084-exec-315] org.apache.catalina.core.StandardWrapperValve.invoke Servlet.service() for servlet [PresentationLayer.Servlet] in context with path [/web] threw exception
 java.io.FileNotFoundException: file.txt (Permission denied)
    at java.io.FileOutputStream.open0(Native Method)
    at java.io.FileOutputStream.open(FileOutputStream.java:270)
    at java.io.FileOutputStream.<init>(FileOutputStream.java:213)
    at java.io.FileOutputStream.<init>(FileOutputStream.java:133)
    at java.io.FileWriter.<init>(FileWriter.java:78)
    at BusinessLayer.IO.<init>(IO.java:24)
    at PresentationLayer.Servlet.doPost(Servlet.java:24)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:648)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:217)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:673)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1500)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1456)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:748)
Martijn Pieters
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Jonas Grønbek
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1 Answers1

1

If you run something on a java ee application server, the current working directory is usually the /bin folder of that server.

Using a relative file position searches the file relative to the current working directory.

One way to display the current working directory is System.out.println( new File(".").getCanonicalPath());

Options:

k5_
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