How to check for unbound request parameters in a Spring MVC controller method?

Question

Given a Spring-MVC controller method:

@RequestMapping(value = "/method")
public void method(ParamModel params) { /*...*/ }

with model class:

public class ParamModel { public int param1; }

The following two results are as expected/desired:

• Request with param1=1: method completes successfully.
• Request with param1=blah: JBWEB000120: The request sent by the client was syntactically incorrect.

However...

• If a request is made with an additional parameter (e.g. nonexistentparam=1), there is no error.

Is there a way to ensure the request is validated and rejected if it includes any parameters that aren't part of this API?

Answer 1

You can use filter to check for invalid parameters as

web.xml

<filter>
    <filter-name>MyFilter</filter-name>
    <filter-class>com.mypackage.filter.MyFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>MyFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

MyFilter Class

import javax.servlet.Filter;
public class MyFilter implements Filter {

    public void destroy() {
    }

    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {
        String requestUrl = request.getParameter("param1");
    //here I am considering 'param1=1' as valid request rest of all are invalid
             if(!requestUrl.equals("1")) {
        logger.info("Invalid Request"); 
        //for invalid request redirect to error or login page
        response.sendRedirect("/error"");           
    } else {
        logger.info("Valid Request");   
    }
    }

    public void init(FilterConfig filterConfig) throws ServletException {
    }       

}

hope this will solve your problem