Problem with sending value of variable with RequestDispatcher

In variable search_for I've got the string value of the value I'm searching开发者_如何转开发 for. But I cannot pass it via RequestDispatcher to jsp. What am I doing wrong?

RequestDispatcher rd = request.getRequestDispatcher("my.jsp?search_for"); 

Soution 1 :

request.setAttribute("paramName", search_for);
RequestDispatcher rd = request.getRequestDispatcher("my.jsp");
rd.forward(request, response);

or

Soution 2 :

RequestDispatcher rd = request.getRequestDispatcher("my.jsp?paramName="+search_for);
rd.forward(request, response);