How to handling submit button from servlet

hi all.....
i have problem during handling button from my servlet .when i click button 3 ,
servlet not forward to outputControl.jsp .But for button1 ,there work well .
what's the kind problem there ? hope some one can show me the best way to do that .i have a more button in JSP that i want to handle from servlet .
all help ,would be appreciated.

code like bellow :
index.jsp :

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
<form name="mainform" action="servletControl" method="POST">
<input type="submit" value="button1" name="button1" />
<input type="submit" value="button2" name="button1" />
<input type="submit" value="button3" name="button3" />
</form>
</body>
</html>

servletControl :
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
String button1Click = request.getParameter("button1");
String button3Click = request.getParameter("button3");
try {
if(button1Click.equalsIgnoreCase("button1")){
RequestDispatcher dispatcher = request.getRequestDispatcher("/outputControl.jsp");
dispatcher.forward( request, response);
}
if(button1Click.equalsIgnoreCase("button2")){
RequestDispatcher dispatcher = request.getRequestDispatcher("/outputControl.jsp");
dispatcher.forward( request, response);
}
if(button3Click.equalsIgnoreCase("button3")){
RequestDispatcher dispatcher = request.getRequestDispatcher("/outputControl.jsp");
dispatcher.forward( request, response);
}
} finally {
out.close();
}
}