second.jsp
<body>
<form action="Result.jsp" method="POST" >
FirstNumber:<input type="text" name="FIRSTNUMBER">
SecondNumber:<input type="text" name="SECONDNUMBER">
ADD:<input type="radio" name="result" value="ADD" >
SUB:<input type="radio" name="result" value="SUB" >
DIV:<input type="radio" name="result" value="DIV" >
MUL:<input type="radio" name="result" value="MUL" >
<input type="submit" value="Result" >
</form>
</body>
</html>
Result.jsp
<body>
<%
String Result = request.getParameter("result");
String s1 = request.getParameter("FIRSTNUMBER");
String s2 = request.getParameter("SECONDNUMBER");
int k=Integer.parseInt(s1);
if (Result.equals("ADD")) {
int add = Integer.parseInt(s1) + Integer.parseInt(s2);
out.println("Result=" + add);
} else if (Result.equals("SUB")) {
int sub = Integer.parseInt(s1) - Integer.parseInt(s2);
out.println("Result=" + sub);
} else if (Result.equals("MUL")) {
int mul = Integer.parseInt(s1) * Integer.parseInt(s2);
out.println("Result=" + mul);
} else if (Result.equals("DIV")) {
int div = Integer.parseInt(s1) / Integer.parseInt(s2);
out.println("Result = " + div);
}
%>
</body>
1. you can only getParameter from pre-page.
2. the radio should have the same name
3. "if" should have {}