Add query string with action in Struts 2

The attribute action

is assumed to be used with a tag <form

. Then the construction

<form name="MyAction.action" action="upload?id=<%=request.getParameter("id")%>&name=<%=request.getParameter("name")%>&age=<%=request.getParameter("age")%>&num=<%=request.getParameter("num")%>" method="POST">

      

        
        
        
      

    

should work with the current context. But in your case, this error message ( Exception Name: org.apache.jasper.JasperException: equal symbol expected

occurs when using a tag <s:form

. So you cannot use this url in an action attribute. This attribute must contain the name of a simple action that will be used to find your action.

"How do we set parameters as a request?"

We actually do this with a tag <s:param

. For example, when using hyperlinks

<s:a action="MyAction">
   <s:param name="id" value="%{id}"/>
   <s:param name="name" value="%{name}"/>
</s:a>

      

        
        
        
      

    

But this construct doesn't work with a tag <s:form

unless you use the special syntax as described in this , and you definitely want to get those parameters if you do in action

String quesyString = request.getQueryString();

      

        
        
        
      

    

and this line must not be empty.

However, this utility is rarely used unless you have a reason to get parameters this way, then alternatively you can always use fields <s:hidden

to hold parameter values. for example

<s:form action="MyAction" method="POST">
    <s:hidden name="id" value="%{id}"/>
    <s:hidden name="name" value="%{name}"/>
</s:form>

      

        
        
        
      

    

These values ​​are passed as parameters and the action attributes are initialized after the handler runs params

. You can also get these parameters directly from the request as

Map<String, String[]> params = (Map<String, String[]>)request.getParameterMap();

      

        
        
        
      

    

However, a more convenient way to do this in your action is to implement ParameterAware

.