title: Best practice to send Json response from Spring controller methods
body: <p>I want to return a string (json string) from a spring controller as response to AJAX call it receives, the response could different based on whether or not I have a @Valid form submitted. This is how I am handling it and wanted to find out if this is considered as best practice? 
  Please note I am using @RestController so @ResonseBody applies all methods. </p>
  
  <pre><code>    @RequestMapping(value = "/save" , method = RequestMethod.POST)
  public String saveScheduledAlert(@Valid ScheduledAlertForm scheduledAlertForm, BindingResult bindingResult) {
      StringBuilder jsonString = new StringBuilder();
      if(bindingResult.hasErrors()){
          jsonString.append("{\"success\" : \"false\"");
          for(ObjectError error : bindingResult.getAllErrors())
              jsonString.append(",\"").append(((FieldError) error).getField()).append("\":\"").append(error.getDefaultMessage()).append("\"");
      } else {
          //save the data
          jsonString.append("{\"success\" : \"true\"");
      }
  
      jsonString.append("}");
      return jsonString.toString();
  
  
  }
  </code></pre>