BAEL-3226: Add java.util.Optional @RequestParam example (eugenp#8279)

Author: kwoyke

spring-mvc-simple/src/main/java/com/baeldung/spring/requestparam/RequestParamController.java

@@ -2,6 +2,7 @@
 
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 
 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.GetMapping;
@@ -31,6 +32,12 @@ public String addFoo(@RequestParam(name = "id") String fooId, @RequestParam Stri
     public String getFoos2(@RequestParam(required = false) String id){ 
         return "ID: " + id;
     }
+
+    @GetMapping("/api/foosOptional")
+    @ResponseBody
+    public String getFoosOptional(@RequestParam Optional<String> id){
+        return "ID: " + id.orElseGet(() -> "not provided");
+    }
 
     @GetMapping("/api/foos3")
     @ResponseBody