将HTML代码作为属性添加到ModelAndView中

Question

Normally if I have to add some html code dynamically, I would like to load from the view with JQuery, and then I render a ModelAndView from the controller using @ResponseBody, since I believe that adding static html from Javascript is not readable and is not reusable. Now I have a case where making a Ajax call I need to check some values from the controller and then render back a map with some values, or render an html code to be added into the DOM. So I have been thinking about how the ModelAndView works, and how can I add a view to be processed on the viewManagement, but only being render if I decide to append that data. So imagine that I would like to have a map with this values

    Map<String, Object> map = new HashMap<>
    map.add("status", "1")

And in another scenario

        Map<String, Object> map = new HashMap<>
        map.add("status", "2")
        map.add("rowErros", "WEB-INF/row_errors.jsp")

And then in the view

      success:function(data)
             if(data.status=="2") $("#rowErrorsTable tbody tr:last").after(data.rowErros);

Regards.

Answer 1

I don't happen to agree that including markup in client-side code is per se less readable or reusable, but regardless, I'm not sure why you would choose to use a ModelAndView for this use case. You could accomplish this on the frontend using success and error callbacks, and by returning appropriate HTTP response codes from your controller method:

@Request(value="/foo")
public ResponseEntity<String> foo() {
    if (conditionIsMet()) {
        return new ResponseEntity<String>("", HttpStatus.OK); // Or some simple JSON string
    } else {
        return new ResponseEntity<String>(HttpStatus.BAD_REQUEST);
    }
}

And on the frontend:

success: doSuccess,
error: function() { $('#error').load('/error.jsp'); } // Optionally sniff for the incoming status code

Assuming your error case is far less frequent than your success case, then you're also:

1. saving your users the bandwidth associated with transmitting the markup of error.jsp with each payload;
2. using HTTP status codes as appropriate responses to HTTP requests, which cleans up and normalizes your API

If you need additional information in your error payload, consider a JSON object that gives the frontend information about the error over and above what the HTTP status code itself provides. That's not necessary in many cases, but it can be useful for BAD_REQUEST situations where you wish to surface what incoming request element caused the request to fail.