Java security

I have made an applet that shows pictures and reads from a text file. Is it possible to allow java to do this in an applet.

Here's the error: java.security.AccessControlException: access denied (java.io.FilePermission . read)

I don't write to the file or anything just read.

Yes.
How are you loading the applet? locally or from a server?
If locally, the applet should be able to read a local file.
If from a server, you'll need to give the applet permission to enable it to read a local file.

Its going on a web page that will obviously be on a server. So what do I need to do to get permission.

Two ways to give permission to an applet:
sign the jar file - I've only done that in testing, but it worked.
Add permissions on the client's computer. This is done with the policytool that comes with java. If there are more than one client, this would be trouble. The policytool program updates the .java.policy file. It hasn't always worked correctly for me.
Here's a sample from my .java.policy file that allows an applet loaded from E:\Java to read the Tutorial or doc subfolders. (I have an applet I use to search those folders while I'm browsing those files)
[

Quote:

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grant codeBase "file:/E:/Java/-" {
permission java.io.FilePermission "E:/", "read";
permission java.io.FilePermission "E:/Java/Tutorial/", "read";
permission java.io.FilePermission "E:/Java/Java-1_6_0/docs/", "read";
};

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I need to have it so that any random person can view it on the internet. Is their on easy way to do this.

Why do you need to read a file from the random person's disk? Doesn't sound like something anyone would want to allow.

I'm not I have a txt file that has a list of words I'm reading in and some pictures I'm displaying that I have to read all this is done on the server but it says when I did it on my computer just making a web page that It couldn't work.

Your applet can read a file from the server it was loaded from without permissions, no problem. Well maybe just the ordinary programming problems But it can be done.

Quote:

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it says when I did it on my computer just making a web page that It couldn't work.

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Not sure what that means. Here's an applet I wrote years ago that reads lots of files from its server: Way Points

Here's the code to read from server:

Code:

---


        URL u = null;
        BufferedReader in;

        if (WayPointDefs.debug) {
            System.out.println("getFile() trying to read: " + fn);
        }
        try {
 
                // We're in an applet - go to server for the file
//                u = new URL(getCodeBase() + CGI_DIR + "/GetFile.pl?" + fn);
                u = new URL(getCodeBase() + fn + (addSfx ==  null ? "" : addSfx));  // do HTTP GET directly
                URLConnection uc = u.openConnection();
                in = new BufferedReader(new InputStreamReader(
                                uc.getInputStream()));
       
            // Read file from "in" and build the lines
            String inputLine;
            while ((inputLine = in.readLine()) != null) {

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When I try to run the applet off my web page it still gives me an error for reading the pictures I can post the code if that's any help.

Are the files located in the Applet's codebase?
It(as per the above code) should work if they are.
Otherwise where are the files you are trying to read?

The Files are located in the same folder as the source and the class files. I use ImageIO to read them in so that I can use them.

Could you post the code where you are trying to read the files using ImageIO?
Where is the HTML file relative to the applet's class files?

Untitled Document click on my Applet

Code:

---

import java.awt.AlphaComposite;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FilenameFilter;
import java.io.IOException;
import java.util.Random;

import javax.imageio.ImageIO;


public class PictureGenerator
{
        private BufferedImage[] myImages;
        private Random rand;
       
        public PictureGenerator()
        {
                rand = new Random();
                this.setupArray();
        }
       
        private void setupArray()
        {
                File[] tempFiles;
                tempFiles = (new File(".").listFiles(
                                new FilenameFilter()
                                {
                                        public boolean accept(File dir, String name)
                                        {
                                                return name.endsWith("JPG") || name.endsWith("GIF")
                                                        || name.endsWith("JPEG") || name.endsWith("jpeg");
                                        }
                                }));
                myImages = new BufferedImage[tempFiles.length];
                for(int i = 0; i < tempFiles.length; i++)
                {
                        myImages[i] = this.createResizedCopy(tempFiles[i]);
                }
               
        }
       
        private BufferedImage createResizedCopy(File aFile)
        {
                int imageType = BufferedImage.TYPE_INT_RGB;
                BufferedImage scaledBI = new BufferedImage(Window.WINDOW_WIDTH, Window.WINDOW_HIEGHT, imageType);
                Graphics2D g = scaledBI.createGraphics();
                g.setComposite(AlphaComposite.Src);

                try
                {
                        g.drawImage(ImageIO.read(aFile), 0, 0, Window.WINDOW_WIDTH, Window.WINDOW_HIEGHT, null);
                }
                catch (IOException e)
                {
                        e.printStackTrace();
                }

                g.dispose();
                return scaledBI;
        }

        public BufferedImage getNewPicture()
        {
                return myImages[rand.nextInt(myImages.length)];
        }
       
}

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There's some confusion about how you are using your program. I thought the program was an applet that was loaded from a server into a browser on some client's computer. The applet was to read a file from the server to get some info and then use that info to read more files from the server.
The code you've shown is using the File class which will try to read the file from the local(client's disk). Not permitted. You must use a URL pointing to the applet's codebase to read files from the server.

Quote:

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tempFiles = (new File(".").listFiles(

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ok how do I do that so it does the same thing

On what system do you want to do it?

Like Windows is that what you mean. Or Internet Explorer.

server or client.

The photos and txt file reside on sever side

then you'll need code on the server to get the list of files and return it to the client. The applet running on the client can NOT see the contents of folders on the server.