BAEL-8372: Add missing code samples from https://www.baeldung.com/exception-handling-for-rest-with-spring (#18504)

Co-authored-by: Ralf Ueberfuhr <[email protected]>

Author: ueberfuhr

spring-boot-rest/src/main/java/com/baeldung/web/error/CustomExceptionObject.java

@@ -0,0 +1,16 @@
+package com.baeldung.web.error;
+
+public class CustomExceptionObject {
+
+    private String message;
+
+    public String getMessage() {
+        return message;
+    }
+
+    public CustomExceptionObject setMessage(String message) {
+        this.message = message;
+        return this;
+    }
+
+}

spring-boot-rest/src/main/java/com/baeldung/web/error/MyGlobalExceptionHandler.java

@@ -1,38 +1,70 @@
 package com.baeldung.web.error;
 
+import com.baeldung.web.exception.CustomException1;
+import com.baeldung.web.exception.CustomException2;
 import com.baeldung.web.exception.CustomException3;
 import com.baeldung.web.exception.CustomException4;
+import com.baeldung.web.exception.CustomException5;
 import org.springframework.http.HttpStatus;
-import org.springframework.http.HttpStatusCode;
 import org.springframework.http.MediaType;
 import org.springframework.http.ProblemDetail;
+import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.ExceptionHandler;
 import org.springframework.web.bind.annotation.ResponseStatus;
 import org.springframework.web.bind.annotation.RestControllerAdvice;
 
+import java.nio.file.AccessDeniedException;
+
 @RestControllerAdvice
 public class MyGlobalExceptionHandler {
 
-    // simple example for global exception handling
     @ResponseStatus(HttpStatus.BAD_REQUEST)
-    @ExceptionHandler(CustomException3.class)
-    public void handleCustomException3() {
+    @ExceptionHandler(CustomException1.class)
+    public void handleException1() {
         //
     }
 
-    // content negotiation
     @ResponseStatus(HttpStatus.BAD_REQUEST)
-    @ExceptionHandler(produces = MediaType.APPLICATION_JSON_VALUE)
-    public ProblemDetail handleCustomException4Json(CustomException4 ex) {
-        String message = "custom exception 4: " + ex.getMessage();
+    @ExceptionHandler
+    public ProblemDetail handleException2(CustomException2 ex) {
         return ProblemDetail
-                .forStatusAndDetail(HttpStatusCode.valueOf(HttpStatus.BAD_REQUEST.value()), message);
+                .forStatusAndDetail(
+                        HttpStatus.BAD_REQUEST,
+                        ex.getMessage()
+                );
     }
 
     @ResponseStatus(HttpStatus.BAD_REQUEST)
-    @ExceptionHandler(produces = MediaType.TEXT_PLAIN_VALUE)
-    public String handleCustomException4Text(CustomException4 ex) {
-        return "custom exception 4: " + ex.getMessage();
+    @ExceptionHandler( produces = MediaType.APPLICATION_JSON_VALUE )
+    public CustomExceptionObject handleException3Json(CustomException3 ex) {
+        return new CustomExceptionObject()
+                .setMessage("custom exception 3: " + ex.getMessage());
+    }
+
+    @ResponseStatus(HttpStatus.BAD_REQUEST)
+    @ExceptionHandler( produces = MediaType.TEXT_PLAIN_VALUE )
+    public String handleException3Text(CustomException3 ex) {
+        return "custom exception 3: " + ex.getMessage();
+    }
+
+    @ResponseStatus(HttpStatus.BAD_REQUEST)
+    @ExceptionHandler({
+            CustomException4.class,
+            CustomException5.class
+    })
+    public ResponseEntity<CustomExceptionObject> handleException45(Exception ex) {
+        return ResponseEntity
+                .badRequest()
+                .body(
+                  new CustomExceptionObject()
+                          .setMessage( "custom exception 4/5: " + ex.getMessage())
+                );
+    }
+
+    @ResponseStatus(value = HttpStatus.FORBIDDEN)
+    @ExceptionHandler( AccessDeniedException.class )
+    public void handleAccessDeniedException() {
+        // ...
     }
 
 }

spring-boot-rest/src/main/java/com/baeldung/web/exception/CustomException5.java

@@ -0,0 +1,13 @@
+package com.baeldung.web.exception;
+
+import java.io.Serial;
+
+public class CustomException5 extends RuntimeException {
+
+    @Serial
+    private static final long serialVersionUID = 1L;
+
+    public CustomException5(String message) {
+        super(message);
+    }
+}