Relative Path to data

[Ed Connery]

Hi.

Assume that I have a file /WEB-INF/data/categories.txt

For obvious reasons I don't want to hard-code a path to the data, but instead want to use a path relative to the application directory. How do I specify that relative path, either within the JSP or within web.xml?

Thanks!

[Edit]It would help if I specified that the app is running under Tomcat 6, but I can't use CATALINA_HOME since that is pointing to Tomcat 5.

[Bear Bibeault]

That depends what you are trying to do.

[Ed Connery]

OK, I didn't mean to be cryptic. The idea is to read from two text files, one containing categories and one containing numbers in text form. These values are displayed by the app. New values are entered in a third column, and those values get written to a third text file. All three files are in the data directory. Does that clarify the situation?

[Bear Bibeault]

The best way to get the contents of the files is to use ServletContext.getResourceAsStream().

[Ed Connery]

OK, forgive the ignorant question, but how do I set/determine the path to the files?

[Bear Bibeault]

Relative to the application root.

[Bear Bibeault]

From the Javadoc:

The path must begin with a / and is interpreted as relative to the current context root

[Ed Connery]

Let me give a code fragment. The lower code works fine, but obviously ties this to the very specific configuration of my computer. I have tried many variations of the code commented out, such as "/WEB-INF/data/new.txt" I had naively thought that one or another of these would define the path relative to the context root. So here I sit with a dreadful example of hard coding. I think I may need a little spoon feeding here. Thanks!

                /*
	String WriteFile = "/pci_sample/WEB-INF/data/new.txt";
	String ReadFile1 = "/pci_sample/WEB-INF/data/categories.txt";
	String ReadFile2 = "/pci_sample/WEB-INF/data/current.txt";
	*/
	String WriteFile = "c:/Program Files/Apache Software Foundation/Tomcat 6.0/webapps/pci_sample/WEB-INF/data/new.txt";
	String ReadFile1 = "c:/Program Files/Apache Software Foundation/Tomcat 6.0/webapps/pci_sample/WEB-INF/data/categories.txt";
	String ReadFile2 = "c:/Program Files/Apache Software Foundation/Tomcat 6.0/webapps/pci_sample/WEB-INF/data/current.txt";   

	try {   
			PrintWriter pw = new PrintWriter(new FileOutputStream(WriteFile));
    		
			int count = 0;
			String[] array1 = new String[count+1];
			int[] array2 = new int[count+1];
			int[] array3 = new int[count+1];
			
			FileReader fr1 = new FileReader(ReadFile1);
			FileReader fr2 = new FileReader(ReadFile2);
			
			BufferedReader in1 = new BufferedReader(fr1);
			BufferedReader in2 = new BufferedReader(fr2);

[Bear Bibeault]

I see no use of getResourceAsStream() in your code.

[Stefan Evans]

The following will probably work.
getResourceAsStream works for reading the files.
to write to the file, you need to get a handle on it with the getRealPath method.

Also fixed variable naming to comply with conventions (lower case letter for variables)
Note that writing to files under your web application directory is not necessarily supported.
Suggestion: put the config file seperate from the web application, so that it won't get over-written at each deployment.

	String writeFilePath = "WEB-INF/data/new.txt";
	String readFile1Path = "WEB-INF/data/categories.txt";
	String readFile2Path = "WEB-INF/data/current.txt";

	try {   
                        ServletContext application = getServletConfig().getServletContext();
                        File writeFile = new File(application.getRealPath(writeFilePath));
			PrintWriter pw = new PrintWriter(new FileOutputStream(writeFile));
    		
			int count = 0;
			String[] array1 = new String[count+1];
			int[] array2 = new int[count+1];
			int[] array3 = new int[count+1];

			InputStream is1 = application.getResourceAsStream(readFile1Path);
			InputStream is2 = application.getResourceAsStream(readFile2Path);

			BufferedReader in1 = new BufferedReader(new InputStreamReader(is1));
			BufferedReader in2 =new BufferedReader(new InputStreamReader(is2));

                        ...
       }

[Ed Connery]

Stefan,

Thank you very much, that did the trick (so now hopefully I will know the trick).

-- Ed