adding error handler. closes #9

src/main/java/guru/springframework/msscbeerservice/web/controller/BeerController.java

@@ -3,6 +3,7 @@
 import guru.springframework.msscbeerservice.web.model.BeerDto;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
+import org.springframework.validation.annotation.Validated;
 import org.springframework.web.bind.annotation.*;
 
 import java.util.UUID;
@@ -23,14 +24,14 @@ public ResponseEntity<BeerDto> getBeerById(@PathVariable("beerId") UUID beerId){
     }
 
     @PostMapping
-    public ResponseEntity saveNewBeer(@RequestBody BeerDto beerDto){
+    public ResponseEntity saveNewBeer(@RequestBody @Validated BeerDto beerDto){
 
         //todo impl
         return new ResponseEntity(HttpStatus.CREATED);
     }
 
     @PutMapping("/{beerId}")
-    public ResponseEntity updateBeerById(@PathVariable("beerId") UUID beerId, @RequestBody BeerDto beerDto){
+    public ResponseEntity updateBeerById(@PathVariable("beerId") UUID beerId, @RequestBody @Validated BeerDto beerDto){
 
         //todo impl
         return new ResponseEntity(HttpStatus.NO_CONTENT);

src/main/java/guru/springframework/msscbeerservice/web/controller/MvcExceptionHandler.java

@@ -0,0 +1,27 @@
+package guru.springframework.msscbeerservice.web.controller;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.ControllerAdvice;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+
+import javax.validation.ConstraintViolationException;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Created by jt on 2019-05-25.
+ */
+@ControllerAdvice
+public class MvcExceptionHandler {
+
+    @ExceptionHandler(ConstraintViolationException.class)
+    public ResponseEntity<List> validationErrorHandler(ConstraintViolationException ex){
+        List<String> errorsList = new ArrayList<>(ex.getConstraintViolations().size());
+
+        ex.getConstraintViolations().forEach(error -> errorsList.add(error.toString()));
+
+        return new ResponseEntity<>(errorsList, HttpStatus.BAD_REQUEST);
+    }
+
+}