What does ":.+" in `{param:.+}` means (java)?

Question

What does the :.+ at {param:.+} mean in this set of code in java? I have tried searching however i do not find any explanation. Someone who knows please do explain it to me. Thank you so much.

BatchFileController.java

@RequestMapping("/runbatchfileparam/{param:.+}")  
public ResultFormat runbatchFile(@PathVariable("param") String fileName) 
{  
RunBatchFile rbf = new RunBatchFile();  
return rbf.runBatch(fileName);  
}  

Answer 1

The colon : is separator between the variable name and a regular expression.

The expression .+ means at least one of any character.