想要if else判断s3是否>=0跳转到postive.jsp或者negative.jsp 下边代码哪里错了
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
My JSP 'sum.jsp' starting page
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
<%
response.setCharacterEncoding("UTF-8");
//String str1=request.getParameter("shuju1");
//String str2=request.getParameter("shuju2");
String str1=(String)session.getAttribute("shuju1");
String str2=(String)session.getAttribute("shuju2");
//double s1=Double.parseDouble(str1);
//double s2=Double.parseDouble(str2);
//double s3=s1+s2;
double s1=Double.parseDouble(str1);
double s2=Double.parseDouble(str2);
double s3=s1+s2;
session.setAttribute("str1","s1");
session.setAttribute("str2","s2");
session.setAttribute("str3","s3");
//request.setAttribute("st1",s1);
//request.setAttribute("st2",s2);
//request.setAttribute("st3",s3);
if(s3>0){
response.sendRedirect("postive.jsp");
}else{
response.sendRedirect("negative.jsp");
}
%>
这是sum.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
My JSP 'input.jsp' starting page
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
整数1:
整数2:
这是input.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<title>My JSP 'postive.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
利用getAttribute方法获取利用setAttribute方法保存的值，并显示！
<%
Double a1=(Double)session.getAttribute("st1");
Double a2=(Double)session.getAttribute("st2");
Double a3=(Double)session.getAttribute("st3");
%>
<%=a1%>+<%=a2%>=<%=a3%>
利用getParameter方法获取获取请求参数，并显示！
<% //String s1=session.getParameter("shuju1");
//String s2=session.getParameter("shuju2");
String s1=(String)session.getAttribute("shuju1");
String s2=(String)session.getAttribute("shuju2");
%>
<%=s1%>+<%=s2%>=<%=a3%>
结果为正!
这是postive.jsp
