Hyder Hashmi wrote:
Hi All,
When I execute the following code in my project folder, it creates the file
in my current folder(project folder).
import java.io.File;
public class CreateFile{
File f = null;
try{
f = new File("test.txt");
bool = f.createNewFile();
System.out.println("File created: "+bool);
}catch(Exception e){
e.printStackTrace();
}
}
I am now calling this class in my servlet.
The servlet is executing perfectly on the tomcat, however, the file is
getting created in the tomcat's bin folder instead of my project folder
placed in the webapps.
If I specify the path, then it creates the file on that location , however,
that will be hardcoding and will not work on the other computer.
Hyder,
apart from all the advice which you have already received, here is maybe a more general
explanation, so that you would understand what you have been told so far.
When you run Tomcat, the process which is really running is a Java Virtual Machine (a
JVM), which compiles and runs the code of Tomcat. Your web application runs under Tomat,
which means basically that it gets compiled and run by the JVM, as a part of Tomcat.
Tomcat is a Java Servlet Engine, which is an application designed to run Java servlets
(like your application), according to the specifications given in the official Java
Servlet Specification. Tomcat is not the only Java Servlet Engine, but they all follow
these same specifications.
If you want your web application to be portable to any Java servlet Engine, your
application must also conform to the rules of the Java Servlet Specification.
One of these "rules" (or, in this case, the absence of one) is about the fact that you
cannot rely on your web application being able to write in whatever directory (if any) is
its "current" directory (even supposing that this exists at all). This "current
directory" is whatever directory the JVM happens to be running in, which you have no way
to know in advance.
(Some day, your application may even be running inside a JVM and a Tomcat that are
entirely in some non-writeable kind of memory.)
So, what everyone has been trying to tell you, is that the only way to do what you
apparently want to do (have that application write something somewhere), and to do this in
a portable way, is to choose a place *outside* of the Tomcat directories, some place that
is guaranteed to be writeable (by the JVM which runs Tomcat and your webapp) because you
created it that way (and you include this in your application's installation
instructions). And to make this portable, your application has to be able to find out
that location (on each system where it may be used), via some *configurable* parameter
that it can read.
And there are some suggestions in previous responses, to tell you how to do
that.
And finally, there is another reason for not writing inside your web application's
directory, even if this was possible : security. If you allow Tomcat to write to your
application directory, then possibly someone can take advantage of this via some
misconfiguration, and overwrite your code with malicious code that would do something else
which you do not want to happen at all. And you would be blamed.
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