将基于Java文本的程序导出到可执行JAR？

Question

I am using Eclipse as my IDE.

I have previously made and exporting my different programs in eclipse as executable jar files, but those were all programs involving frames. I was messing around with the classic text based programs I had and decided that I wanted to export the said text-based programs. However, when I try and do this I am left with a jar file that does not run or do anything. I have had no success in having my text-based programs to run outside of Eclipse.

Answer 1

The odds are that the jar file IS running. But the problem is that (I'm assuming here) you're using System.out and System.in for your i/o. When you're running a jar file (with double-click ) you have no visible console.

There are two ways to combat this:

-Either create a gui and use that as your i/o

-Or you can run the jar file from the command line ("java -jar yourjar.jar" <- on windows cmd) and the input and output will be done through the command window you used to run the jar.

EDIT: Added some information about fixing: "java is not a recognized..."

You have two options here, when you're running your jar with the command "java -jar yourjar.jar"; you could replace "java" with the full path to your java executable, so for example:

"C:\Program Files\Java\jdk1.8.0_05\bin\java" -jar yourjar.jar

or

"C:\Program Files\Java\jdk1.8.0_05\jre\bin\java" -jar yourjar.jar

This does become annoying though, so the best things to do is set up java in your system environmental variables. Open your 'Start Menu', right-click on 'Computer' and select 'Properties'. Once you're here select 'Advanced System Settings', and then click on the 'Environmental Variables' button.

Now what I like to do is create another two variables (if you don't plan on doing any of this on other users, just do it in your user-variables for your account section), "JDK_HOME" and "JAVA_HOME". I personally have both of these point to the same place just because of a little error I was having with something. However in your case it sounds like you only need one, we'll go with JDK_HOME:

So add your variable:

And then we want to actually have it on the Systems Path, so look through the variables and find one called "PATH", edit this one and we're going to be adding the JDK_HOME variables directory and the bin folder to it:

When appending multiple directories to the Path variable, each are separated by a semi-colon. You'll note that I am adding the variable JDK_HOME by specifying %JDK_HOME%, but I am then adding '/bin' to it, this is because we are interested in using the Java executable within the bin directory. Now that you have that sorted, close out of your environmental variables configuration, and try again, you should now have the command "java" work.

-Thomas