[FIXED] Encoded Comma in URL is read as List in Spring

Issue

I have a REST Component in Spring. Simplified, it looks like this:

@RequestMapping(value = "/route", method = RequestMethod.GET)
public Object thisIsTheMethod(@RequestParam(value = "value", required = false) List<String> values) {
    return OtherClass.doTheThing(values);
}

This is used to consume a list of Strings of arbitrary length. You could do it a number of ways:

localhost:8080/route?value=this&value=that

OR

localhost:8080/route?value=this,that

Now let's say I want to pass in one string which contains a comma: value,1. How would I go about doing that? Replacing the comma with %2C results in a list of 2 values ("value", "1"). Putting anything in quotes, or escaped quotes, has similar problems. It looks like it works when I have multiple parameters and use the multiple-values pattern, though not when I use the comma-separated pattern.

Solution

You can set your Delimiter. The comma is just the default one used in org.springframework.boot.convert.DelimitedStringToCollectionConverter when it isn't set. If you wish, you can disable the Delimiter completely. For your code, it would look like this:

import org.springframework.boot.convert.Delimiter;

@RequestMapping(value = "/route", method = RequestMethod.GET)
public Object thisIsTheMethod(@Delimiter(Delimiter.None) @RequestParam(value = "value", required = false) List<String> values) {
    return OtherClass.doTheThing(values);
}

Answered By - Grez
Answer Checked By - Senaida (JavaFixing Volunteer)