CODEWITHSUNDEEP
spring-mvc
Mary
Mary

Reputation: 1595

@FormParameter in spring -mvc

In spring-mvc, in controller code i have seen the form parameters explicitly passed . Why is this done?

public ModelAndView methodXX(
        @FormParam("arg1") String arg1,
        @FormParam("arg2") String arg2,
        @FormParam("arg3") String arg3,
        HttpServletRequest request, HttpServletResponse response)

If the call were as follows:

public ModelAndView methodXX(HttpServletRequest request,HttpServletResponse response)

The arg1,arg2,arg3 could still be obtained by using

request.getParameter("arg1") and so on for the others. What is the benefit of using FormParam?

Upvotes: 1

Views: 8061

Answers (2)

shivbits
shivbits

Reputation: 121

If you use the application/x-www-form-urlencoded content-type in your request, you can send data in the POST body.

method = RequestMethod.POST, consumes = "application/x-www-form-urlencoded"

In this case, the data in POST request body has to be of the format arg1=1&arg2=5&arg3=6

Choose 'raw' for request body type in Postman plugin for Chrome browser, to test this out.

also set the Header: Content-Type application/x-www-form-urlencoded

Upvotes: 0

Sotirios Delimanolis
Sotirios Delimanolis

Reputation: 279880

There is no @FormParam annotation in Spring MVC, at least not in any version I am aware of. Spring MVC has @RequestParam.

The main benefit is to reduce the code repetition in calling 

request.getParameter("arg1");

However, @RequestParam also has other parameters, namely required and defaultValue. With required set to true, Spring will throw exceptions if getParameter returns null. With required set to false, Spring will call getParameter and pass whatever it finds, whether it's null or an actual value.

With defaultValue, you can set a default value if getParameter returns null.

So instead of doing

String arg1 = request.getParameter("arg1");
if (arg1 == null) {
    arg1 = "default value";
}

you simply add the following as a method parameter

..., @RequestParam(value = "arg1", defaultValue = "default value") String arg1, ...

Upvotes: 9

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