Thread: Importing Apache Commons?

Hi!

I've got this annoying error message when trying to import:

import org.apache.commons.codec.binary.Hex.encodeHex;

"Import org.apache.commons.codec cannot be resolved", which after searching seems to be a somewhat common problem. The solution being to go to: FileUpload - Home and download some jar file and add it to the /web-inf/lib folder. I've done this (or at least I think I have, the file is every so confusing), yet the error persists even after adding the jar file in "add external jar files" and restarting eclipse.

The jar file I added is called "commons-fileupload-1.3.1.jar" which is the only one I could find in the zip file. I've searched around looking at numerous threads about the issue, several of them sadly several years old, with no success.

What exactly am I doing wrong? Surely installing a library to eclipse shouldn't be this complicated?

It's a common problem for those learning to use their IDE of any kind. I typically use Method 2 in this link, but that may not be the best approach for a project that may be exported in the future.

I'm afraid even that doesn't seem to work, I tried several of the Apache folders, zips, java files, none of it removed the error message.

I tried several of the Apache folders, zips, java files

This comment is confusing. What jar file do you have? Never mind, it sounds like you have them all except the right one added the right way.

Step by step:

Did you download this library?: org.apache.commons.codec (Download the binary.)

Hm, no I downloaded these ones: FileUpload - Download Apache Commons FileUpload, tried both the bin and source, but no wonder they didn't work if neither was correct. ^^

I've downloaded the one you linked, what folder should I place it in?

Any folder you'd like. I keep a separate folder for all of my 3rd party .jar files. You can then add that folder to your classpath, and/or add each .jar to the project's builders (per the earlier link) in your IDE. The specific approach you use may only matter when it comes time to export the completed project, if you need to.

Strange, something is still wrong.

1: I download the file commons-codec-1.9-bin.zip
2: I extract the folder to a location where I can easily find it.
3: I right click the project, go down to build path, and select "configure build path".
4: I press add variable.
5: I press configure variables.
6: I press new.
7: I enter the name "APACHE_JARS, press folder and locate to the commons-codec-1.9-bin folder, I select it and press OK.
(Tried stopping here, still recieve error)
8: I press OK, eclipse rebuilds.
9: I select the APACHE_JARS and press Extend.
10: I select all of the jar files available:
commons-codec-1.9-javadoc.jar
commons-codec-1.9-sourcer.jar
commons-codec-1.9-test-sourcers.jar
commons-codec-1.9-tests.jar
commons-codec-1.9.jar

I press OK until all of the windows are closed, and still have the error. Restarting eclipse doesn't solve it.

Edit:

On second look, it seems it did and didn't solve the issue, it accepts:

import org.apache.commons.codec.binary.*;

But not:

import org.apache.commons.codec.binary.Hex.encodeHex;

With the error message of: "The import org.apache.commons.codec.binary.Hex.encodeHex cannot be resolved"

It doesn't seem to be able to find anything past binary, so the issue remains. =/

You've made progress, successfully added the needed .jar file to your project, but now the specific import doesn't exist in the latest version of the Apace Commons Codec package. (Or maybe it never existed.) You'll either need to revert to the earlier version that did have the necessary import, OR inspect the later packages and adjust the import as needed.

I found this discussion among others having the same problem with a possible workaround near the bottom.