Handle api call exceptions using RestTemplate.

RestTemplateExceptionHandleExample.java

     private BaseResponseBody<?> handleExceptions(Exception e) {
     try {
         if (e instanceof HttpServerErrorException) {
             if (((HttpServerErrorException) e).getStatusCode() == HttpStatus.INTERNAL_SERVER_ERROR) {
                 String responseBody500 = ((HttpServerErrorException) e).getResponseBodyAsString();
                 logger.error("[NSU] Nsu server return INTERNAL SERVER ERROR and the response body is : {}", responseBody500);
                 return ResponseBuilder.getFailureResponse(HttpStatus.SERVICE_UNAVAILABLE,
                         "NSU System did not respond as per our expectation. " +
                                 "You can try again or you can proceed to collect using 'North South University (Offline)' merchant.", e);
             }
         }
         //if (e instanceof ResourceAccessException) {
         Throwable cause = e.getCause();
         if (cause instanceof ConnectException) {
             //@INFO This usually means the server is unreachable. This could be due to the server being down, incorrect IP/hostname, or network issues.
             return ResponseBuilder.getFailureResponse(HttpStatus.SERVICE_UNAVAILABLE,
                     "Unable to connect to the NSU System. Please check if the system is up and reachable " +
                             "or you can proceed to collect using 'North South University (Offline)' merchant.", e);
         } else if (cause instanceof SocketTimeoutException) {
             //@INFO This happens when the connection or read operation times out. You might need to increase your timeout settings or check the server's response times.
             return ResponseBuilder.getFailureResponse(HttpStatus.SERVICE_UNAVAILABLE,
                     "NSU System did not respond within the anticipated time. " +
                             "Please contact with your administrator.", e);
         } else if (cause instanceof UnknownHostException) {
             //@INFO This indicates a DNS issue where the hostname cannot be resolved to an IP address.
             return ResponseBuilder.getFailureResponse(HttpStatus.SERVICE_UNAVAILABLE,
                     "NSU System host could not be determined. " +
                             "You can proceed to collect using 'North South University (Offline)' merchant.", e);
         } else if (cause instanceof NoRouteToHostException) {
             //@INFO This means that the networking system is unable to find a route to the specified host, often due to network configuration issues.
             return ResponseBuilder.getFailureResponse(HttpStatus.SERVICE_UNAVAILABLE,
                     "No route to the NSU System host." +
                             " You can proceed to collect using 'North South University (Offline)' merchant.", e);
         } else if (cause instanceof PortUnreachableException) {
             //specific exception in Java's networking API that occurs when an attempt to connect to a specific port on a remote host fails because the port is unreachable
             return ResponseBuilder.getFailureResponse(HttpStatus.SERVICE_UNAVAILABLE,
                     "Defined port Unreachable." +
                             " You can proceed to collect using 'North South University (Offline)' merchant.", e);
         } else if (cause instanceof ConnectionResetException) {
             //that indicates a connection was forcibly closed by a peer. This exception often occurs when the server unexpectedly terminates the connection.
             return ResponseBuilder.getFailureResponse(HttpStatus.SERVICE_UNAVAILABLE,
                     "Server unexpectedly terminates the connection." +
                             " Please contact with your administrator.", e);
         } else if (cause instanceof IOException) {
             //@INFO This is a broad exception for I/O issues, which could be due to stream interruptions, unexpected closures, or other input/output errors
             return ResponseBuilder.getFailureResponse(HttpStatus.SERVICE_UNAVAILABLE,
                     "An I/O error occurred while trying to reach the NSU System. " +
                             "Please contact with your administrator.", e);
         }
         // }
         return ResponseBuilder.getFailureResponse(HttpStatus.INTERNAL_SERVER_ERROR,
                 "[NSU] Something went wrong during call NSU API. Please contact with your administrator.", e);
     } catch (Exception exception) {
         logger.error("[NSU] Something went wrong during handle NSU api call exception :{}", exception.getMessage(), exception);
         return ResponseBuilder.getFailureResponse(HttpStatus.INTERNAL_SERVER_ERROR,
                 "[NSU] Something went wrong during call NSU API. Please contact with your administrator.", exception);
     }
 }