// ① 基于 if/else 判断
if(deletePage(page) == E_OK){
 if(registry.deleteReference(page.name) == E_OK){
  if(configKeys.deleteKey(page.name.makeKey()) == E_OK){
   logger.log("page deleted");
  }else{
   logger.log("configKey not deleted");
  }
 }else{
  logger.log("deleteReference from registry failed");
 }
}else{
 logger.log("delete failed");
 return E_RROR;
}

// ② 基于异常处理
try{
 deletePage(page);
 registry.deleteReference(page.name);
 configKeys.deleteKey(page.name.makeKey());
}catch(Exception e){
 logError(e);
}

// ③ 优雅的异常处理逻辑
public void delete(Page page){
 try{
  deletePageAndAllReferences(page);
 }catch(Exception e){
  logError(e);
 }
}

private void deletePageAndAllReferences(Page page) throw Exception{
 deletePage(page);
 registry.deleteReference(page.name);
 configKeys.deleteKey(page.name.makeKey());
}

private void logError(Exception e){
 logger.log(e.getMessage());
}

+ resources
 + templates
  + error
   - 401.html
   - 404.html
   - 500.html

/**
 * 统一响应
 * @author anoy
 */
public class ResponseBean<T> {

  private int code;

  private String message;

  private T data;

  public ResponseBean(){}

  public ResponseBean(ExceptionEnum exceptionEnum){
    this.code = exceptionEnum.getCode();
    this.message = exceptionEnum.getMessage();
  }

  // 省略 setter/getter
}

/**
 * 异常类型枚举
 * @author anoy
 */
public enum ExceptionEnum {

  GIRL_FRIEND_NOT_FOUND(100000, "girl friend not found");

  private int code;

  private String message;

  ExceptionEnum(int code, String message){
    this.code = code;
    this.message = message;
  }

  public int getCode() {
    return code;
  }

  public String getMessage() {
    return message;
  }
}

@Controller
public class UserController {

  @RequestMapping("/friend/{id}")
  public String friend(@PathVariable("id") Long id) throws GirlFriendNotFoundException {
    if (id == 1L){
      throw new GirlFriendNotFoundException();
    }
    return "friend";
  }

  @ExceptionHandler(GirlFriendNotFoundException.class)
  @ResponseBody
  public ResponseBean handleGirlFriendNotFound(GirlFriendNotFoundException exception){
    loggerError(exception);
    return new ResponseBean(ExceptionEnum.GIRL_FRIEND_NOT_FOUND);
  }
  
  private void logError(Exception e){
    logger.error(e.getMessage());
  }
}

@ControllerAdvice
public class GlobalExceptionHandler {

  @ExceptionHandler(RedisConnectionFailureException.class)
  public void handlerRedisConnectionFailureException(RedisConnectionFailureException exception){
    logError(exception);
    noticeToDev();
  }

  private void logError(Exception e){
    logger.error(e.getMessage());
  }

  private void noticeToDev(){
    // 通知具体开发人员
  }

}