Sping Boot REST api validation + error handling

Author: giaunv

springboot-examples/springboot-restapi-validation/pom.xml

@@ -11,7 +11,7 @@
     <parent>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-parent</artifactId>
-        <version>2.1.4.RELEASE</version>
+        <version>2.1.5.RELEASE</version>
     </parent>
 
     <properties>

…springboot/restful/ExceptionHandler.java …ingboot/restful/APIExceptionHandler.javaspringboot-examples/springboot-restapi-validation/src/main/java/com/hellokoding/springboot/restful/ExceptionHandler.java renamed to springboot-examples/springboot-restapi-validation/src/main/java/com/hellokoding/springboot/restful/APIExceptionHandler.java springboot-examples/springboot-restapi-validation/src/main/java/com/hellokoding/springboot/restful/ExceptionHandler.java renamed to springboot-examples/springboot-restapi-validation/src/main/java/com/hellokoding/springboot/restful/APIExceptionHandler.java

@@ -1,27 +1,40 @@
 package com.hellokoding.springboot.restful;
 
-import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
+import org.springframework.validation.FieldError;
 import org.springframework.web.bind.MethodArgumentNotValidException;
 import org.springframework.web.bind.annotation.ControllerAdvice;
+import org.springframework.web.bind.annotation.ExceptionHandler;
 import org.springframework.web.context.request.WebRequest;
 import org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler;
 
-@ControllerAdvice
+import javax.validation.ConstraintViolationException;
+
 @Slf4j
-@RequiredArgsConstructor
-public class ExceptionHandler extends ResponseEntityExceptionHandler {
+@ControllerAdvice
+public class APIExceptionHandler extends ResponseEntityExceptionHandler {
     @Override
     protected ResponseEntity handleMethodArgumentNotValid(MethodArgumentNotValidException ex, HttpHeaders headers, HttpStatus status, WebRequest request) {
         log.error(ex.getMessage(), ex);
 
+        FieldError fieldError = ex.getBindingResult().getFieldError();
         ResponseDTO responseDTO = ResponseDTO.builder()
             .status(status.toString())
-            .message(ex.getBindingResult().getFieldError().getDefaultMessage())
-            .body(ex.getBindingResult().getTarget()).build();
+            .message(fieldError.getDefaultMessage()).build();
+
+        return ResponseEntity.badRequest().body(responseDTO);
+    }
+
+    @ExceptionHandler(ConstraintViolationException.class)
+    public final ResponseEntity<Object> handleConstraintViolationException(Exception ex, WebRequest request) {
+        log.error(ex.getMessage(), ex);
+
+        ResponseDTO responseDTO = ResponseDTO.builder()
+            .status(HttpStatus.BAD_REQUEST.toString())
+            .message(ex.getMessage()).build();
 
         return ResponseEntity.badRequest().body(responseDTO);
     }

springboot-examples/springboot-restapi-validation/src/main/java/com/hellokoding/springboot/restful/Application.java

@@ -3,6 +3,7 @@
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 
+
 @SpringBootApplication
 public class Application {
     public static void main(String[] args) {

springboot-examples/springboot-restapi-validation/src/main/java/com/hellokoding/springboot/restful/ResponseDTO.java

@@ -7,6 +7,9 @@
 @Builder
 public class ResponseDTO<T> {
     private String status;
-    private String message;
+
+    @Builder.Default
+    private String message = "Success!";
+
     private T body;
 }

springboot-examples/springboot-restapi-validation/src/main/java/com/hellokoding/springboot/restful/product/ProductAPI.java

@@ -1,16 +1,17 @@
 package com.hellokoding.springboot.restful.product;
 
+import com.hellokoding.springboot.restful.ResponseDTO;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
+import org.springframework.validation.annotation.Validated;
 import org.springframework.web.bind.annotation.*;
 
 import javax.validation.Valid;
-import java.util.List;
-
 
 @RestController
 @RequestMapping("/api/v1/products")
+@Validated
 public class ProductAPI {
     private final ProductService productService;
 
@@ -20,29 +21,48 @@ public ProductAPI(ProductService productService) {
     }
 
     @GetMapping
-    public ResponseEntity<List<Product>> findAll() {
-        return ResponseEntity.ok(productService.findAll());
+    public ResponseEntity<ResponseDTO> findAll() {
+        ResponseDTO responseDTO = ResponseDTO.builder()
+            .status(HttpStatus.OK.toString())
+            .body(productService.findAll()).build();
+
+        return ResponseEntity.ok(responseDTO);
     }
 
     @GetMapping("/{id}")
-    public ResponseEntity<Product> findById(@PathVariable @ProductIDExisting Long id) {
-        return ResponseEntity.ok(productService.findById(id).get());
+    public ResponseEntity<ResponseDTO> findById(@PathVariable @ProductIDExisting Long id) {
+        ResponseDTO responseDTO = ResponseDTO.builder()
+            .status(HttpStatus.OK.toString())
+            .body(productService.findById(id)).build();
+
+        return ResponseEntity.ok(responseDTO);
     }
 
     @PostMapping
-    public ResponseEntity<Product> create(@Valid @RequestBody Product product) {
-        return ResponseEntity.status(HttpStatus.CREATED).body(productService.save(product));
+    public ResponseEntity<ResponseDTO> create(@RequestBody Product product) {
+        ResponseDTO responseDTO = ResponseDTO.builder()
+            .status(HttpStatus.CREATED.toString())
+            .body(productService.save(product)).build();
+
+        return ResponseEntity.status(HttpStatus.CREATED).body(responseDTO);
     }
 
     @PutMapping("/{id}")
-    public ResponseEntity<Product> update(@PathVariable Long id, @Valid @RequestBody Product product) {
-        return ResponseEntity.accepted().body(productService.save(product));
+    public ResponseEntity<ResponseDTO> update(@PathVariable Long id, @RequestBody @Valid Product product) {
+        ResponseDTO responseDTO = ResponseDTO.builder()
+            .status(HttpStatus.ACCEPTED.toString())
+            .body(productService.save(product)).build();
+
+        return ResponseEntity.accepted().body(responseDTO);
     }
 
     @DeleteMapping("/{id}")
-    public ResponseEntity delete(@PathVariable @ProductIDExisting Long id) {
+    public ResponseEntity<ResponseDTO> delete(@PathVariable @ProductIDExisting Long id) {
         productService.deleteById(id);
 
-        return ResponseEntity.accepted().build();
+        ResponseDTO responseDTO = ResponseDTO.builder()
+            .status(HttpStatus.ACCEPTED.toString()).build();
+
+        return ResponseEntity.accepted().body(responseDTO);
     }
 }

springboot-examples/springboot-restapi-validation/src/main/java/com/hellokoding/springboot/restful/product/ProductIDExistingValidator.java

@@ -1,6 +1,5 @@
 package com.hellokoding.springboot.restful.product;
 
-import lombok.NoArgsConstructor;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Component;
 
@@ -9,7 +8,6 @@
 import java.util.Objects;
 
 @Component
-@NoArgsConstructor
 public class ProductIDExistingValidator implements ConstraintValidator<ProductIDExisting, Long> {
     @Autowired
     private ProductService productService;

springboot-examples/springboot-restapi-validation/src/main/resources/ValidationMessages.properties

@@ -1,2 +1,2 @@
-NotNull.name=This field is required
+NotNull.name=Name is required
 ProductIDExisting=Product ID ${validatedValue} is not existing