feat(error): add global exception handler

Author: xanderbilla

src/main/java/com/example/demo/exception/GlobalExceptionHandler.java

@@ -0,0 +1,120 @@
+package com.example.demo.exception;
+
+import com.example.demo.dto.ApiResponse;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.RestControllerAdvice;
+import org.springframework.web.context.request.WebRequest;
+import org.springframework.web.servlet.NoHandlerFoundException;
+
+import java.time.LocalDateTime;
+import java.util.HashMap;
+import java.util.Map;
+
+@RestControllerAdvice
+public class GlobalExceptionHandler {
+
+    @ExceptionHandler(NoHandlerFoundException.class)
+    public ResponseEntity<ApiResponse<Object>> handleNotFound(NoHandlerFoundException ex, WebRequest request) {
+        ApiResponse<Object> response = ApiResponse.builder()
+                .message("Endpoint not found: " + ex.getRequestURL())
+                .timestamp(LocalDateTime.now())
+                .status(HttpStatus.NOT_FOUND.value())
+                .build();
+
+        return ResponseEntity.status(HttpStatus.NOT_FOUND).body(response);
+    }
+
+    @ExceptionHandler(IllegalArgumentException.class)
+    public ResponseEntity<ApiResponse<Object>> handleIllegalArgument(IllegalArgumentException ex) {
+        ApiResponse<Object> response = ApiResponse.builder()
+                .message("Invalid request: " + ex.getMessage())
+                .timestamp(LocalDateTime.now())
+                .status(HttpStatus.BAD_REQUEST.value())
+                .build();
+
+        return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(response);
+    }
+
+    @ExceptionHandler(RuntimeException.class)
+    public ResponseEntity<ApiResponse<Object>> handleRuntimeException(RuntimeException ex) {
+        ApiResponse<Object> response = ApiResponse.builder()
+                .message("Internal server error: " + ex.getMessage())
+                .timestamp(LocalDateTime.now())
+                .status(HttpStatus.INTERNAL_SERVER_ERROR.value())
+                .build();
+
+        return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).body(response);
+    }
+
+    @ExceptionHandler(Exception.class)
+    public ResponseEntity<ApiResponse<Object>> handleGenericException(Exception ex) {
+        Map<String, Object> errorDetails = new HashMap<>();
+        errorDetails.put("exception", ex.getClass().getSimpleName());
+        errorDetails.put("cause", ex.getCause() != null ? ex.getCause().getMessage() : "Unknown");
+
+        ApiResponse<Object> response = ApiResponse.builder()
+                .message("An unexpected error occurred: " + ex.getMessage())
+                .timestamp(LocalDateTime.now())
+                .status(HttpStatus.INTERNAL_SERVER_ERROR.value())
+                .data(errorDetails)
+                .build();
+
+        return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).body(response);
+    }
+
+    @ExceptionHandler(org.springframework.web.HttpRequestMethodNotSupportedException.class)
+    public ResponseEntity<ApiResponse<Object>> handleMethodNotSupported(
+            org.springframework.web.HttpRequestMethodNotSupportedException ex) {
+
+        Map<String, Object> errorDetails = new HashMap<>();
+        errorDetails.put("method", ex.getMethod());
+        errorDetails.put("supportedMethods", ex.getSupportedMethods());
+
+        ApiResponse<Object> response = ApiResponse.builder()
+                .message("HTTP method not supported: " + ex.getMethod())
+                .timestamp(LocalDateTime.now())
+                .status(HttpStatus.METHOD_NOT_ALLOWED.value())
+                .data(errorDetails)
+                .build();
+
+        return ResponseEntity.status(HttpStatus.METHOD_NOT_ALLOWED).body(response);
+    }
+
+    @ExceptionHandler(org.springframework.web.bind.MissingServletRequestParameterException.class)
+    public ResponseEntity<ApiResponse<Object>> handleMissingParameter(
+            org.springframework.web.bind.MissingServletRequestParameterException ex) {
+
+        Map<String, Object> errorDetails = new HashMap<>();
+        errorDetails.put("parameterName", ex.getParameterName());
+        errorDetails.put("parameterType", ex.getParameterType());
+
+        ApiResponse<Object> response = ApiResponse.builder()
+                .message("Missing required parameter: " + ex.getParameterName())
+                .timestamp(LocalDateTime.now())
+                .status(HttpStatus.BAD_REQUEST.value())
+                .data(errorDetails)
+                .build();
+
+        return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(response);
+    }
+
+    @ExceptionHandler(org.springframework.web.bind.MethodArgumentNotValidException.class)
+    public ResponseEntity<ApiResponse<Object>> handleValidationException(
+            org.springframework.web.bind.MethodArgumentNotValidException ex) {
+
+        Map<String, Object> errorDetails = new HashMap<>();
+        ex.getBindingResult().getFieldErrors()
+                .forEach(error -> errorDetails.put(error.getField(), error.getDefaultMessage()));
+
+        ApiResponse<Object> response = ApiResponse.builder()
+                .message("Validation failed")
+                .timestamp(LocalDateTime.now())
+                .status(HttpStatus.BAD_REQUEST.value())
+                .data(errorDetails)
+                .build();
+
+        return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(response);
+    }
+}