[FIXED] Spring set default PathVariable

Issue

I want to pass in my parameters to my web service in the format:

http://.../greetings/neil/1

Rather than

rel="noreferrer">http://.../greetings?name=neil&id=1

So I changed my code from (note, I've only included the first parameter in the code):

@RequestMapping("/greeting")
public Greeting greeting(@RequestParam(value="name", defaultValue="World") String name) {
    return new Greeting(counter.incrementAndGet(),
                        String.format(template, name));
}

to:

@RequestMapping
public Greeting greeting(@PathVariable String name) {
    return new Greeting(counter.incrementAndGet(),
                        String.format(template, name));
}

which works, however I do not know how to add default values to @PathVariable so that for example:

http://.../greetings/

http://.../greetings/neil/

would work as it does with query parameters.

How do I do this? I thought maybe it would pass null, but it just generates a page error.

I guess the answer might be to add multiple overloads, but that sounds a bit messy.

thanks.

thanks.

Solution

How about the following way? I am using java.util.Optional class which acts as a wrapper over objects that can be null or not-null.

@RequestMapping
public Greeting greeting(@PathVariable Optional<String> name) {
    String newName = "";  
    if (name.isPresent()) {
        newName = name.get()   //returns the id
    }
    return new Greeting(counter.incrementAndGet(),
                        String.format(template, newName));
}

Alternately, you can define two separate request mapping handlers:

@RequestMapping("/greeting")
public Greeting defaultGreeting()

AND

@RequestMapping("/greeting/{name}")
public Greeting withNameGreeting(@PathVariable String name)

Answered By - VHS
Answer Checked By - Mary Flores (JavaFixing Volunteer)