java - Spring MVC: Error 400 The request sent by the client was syntactically incorrect

Question

This seems to be a common issue. I have gone all the answers given in SO but could not make it work.
I am trying to integrate Spring MVC+Freemarker in already existing web application. It works fine for the GET request and Freemarker Template reads java object provided by Controller without any issue.
But Form submission is not able to hit Controller method. Finally I made log4j work. Here is the error I am getting:
Error

    HandlerMethod details: 
    Controller [application.entry.controller.UserController]
    Method [public void application.entry.controller.UserController.handleSave(java.lang.String)]

    org.springframework.web.bind.MissingServletRequestParameterException: 
Required String parameter 'action' is not present

Freemarker:

<form method="POST" action="save.html">
  ------------
  <input type="submit" class="btnnew" name="saveWithoutValidation" value="Save Without Validation"></input>
  <input type="submit" class="btnnew" name="submit" value="Submit"></input>
</form>

context-root is PORTAL.
spring-servlet.xml

<bean id="viewResolver" class="org.springframework.web.servlet.view.freemarker.FreeMarkerViewResolver">
      <property name="cache" value="true"/>
      <property name="prefix" value=""/>
      <property name="suffix" value=".ftl"/>

web.xml

<servlet>
        <servlet-name>spring</servlet-name>
        <servlet-class>
            org.springframework.web.servlet.DispatcherServlet
        </servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>spring</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

Controller

@RequestMapping(value="/save", method=RequestMethod.POST)
    public void handleSave(@RequestParam String action){

        if( action.equals("submit") ){
            System.out.println("Damn! You clicked submit");
        }
        else if( action.equals("saveWithoutValidation") ){
           System.out.println("Sweet! You want no string attached.");
        }

    }

For logs I have tried to add log4j.logger.org.springframework.web=DEBUG to my existing log4j.properties but it didn't work.

Answer 1

The @RequestParam String action suggests there is a parameter present within the request with the name action which is absent in your form. You must either:

1. Submit a parameter named value e.g. <input name="action" />
2. Set the required parameter to false within the @RequestParam e.g. @RequestParam(required=false)