Comparing versions (strings)

Question

I'm not sure as to how I'd go about comparing two version strings, and include support for "SNAPSHOT" in the version name.

An example: I have two version strings, "1.9.9" and "2.0.0". I want to return a boolean (true) if the second string is greater than the first string. I've used this: https://stackoverflow.com/a/6702029/1442718

It works perfectly.

However, an example like this won't work with that code: I have two version strings, "2.0.0-SNAPSHOT" and "2.0.0". Obviously the SNAPSHOT is one version behind 2.0.0, but this method won't pick it up and throw a NumberFormatException, instead of returning -1 which implies it is a version below.

Any suggestions? Thanks.

• jalynn2: Search for "-SNAPSHOT" in the string, and use the substring that precedes it if found for the numerical comparison
• Turing85: You could use boolean isSnapshot1 = str1.endsWith("SNAPSHOT"). In case of equality regarding version-numbers, the "snapshot"-one wins. If both are snapshot and the versions are equal, you cannot distinguish their order.
• Armaiti: Check your string to see if it contain "SNAPSHOT" contains("SNAPSHOT") and remove it from the string using replace("SNAPSHOT", "")
• Marko Gresak: If you don't mind adding extra library, you can use maven's ComparableVersion class.
• Faris Rehman: @jalynn2 But that would return 0 as the strings are the same then..

Answer 1

You could use something like this:

[...]
boolean isSnapshot1 = str1.endsWith("SNAPSHOT");
boolean isSnapshot2 = str2.endsWith("SNAPSHOT");
[...]
if (...) { // if version-number are equal
 if (isSnapshot1 && !isSnapshot2) { // same versions, but first is snapshot
 return (1);
 }
 if { // same versions, but secont is snapshot
 return (-1);
 }
 // else { Neither or both are snapshots, versions are equals -> cannot distinguish their order
 return (0);
 // }
}
[...]

This should to the job.

• Faris Rehman: Sorry for the late reply, yeah thanks, that's what I did and it works great.