login.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<form action="select.jsp" method="post">
<table>
<tr>
<td align="right">用户名：</td>
<td><input type="text" name="username"></td>
</tr>
<tr>
<td align="right">班级：</td>
<td><select name="grade">
<option value="一班">一班</option>
<option value="二班">二班</option>
<option value="三班">三班</option>
<option value="四班">四班</option>
<option value="五班">五班</option>
</select>
</td>
</tr>
<tr>
<td align="center"><input type="submit" value="提交">
</td>
</tr>
</table></form>
</body>
</html>
select.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<form action="success.jsp" method="post">
<%
request.setCharacterEncoding("UTF-8");
String username=request.getParameter("username");
String grade=request.getParameter("grade");
%>
<h3>一：1+3=(用英文回答)(小写):<input type="text" name="number"></h3>
<h3>二：the pen is __. </h3>
<input type="radio" name="english" value="A">A.me
<input type="radio" name="english" value="B">B.my
<input type="radio" name="english" value="C">C.mine
<h3>三：选择的英文是：(多选)</h3>
<input type="checkbox" name="check" value="select" >select
<input type="checkbox" name="check" value="choose" >choose
<input type="checkbox" name="check" value="chose" >chose
<p><input type="submit" value="提交">
<%
if(username.equals(""))
{
%>
<jsp:forward page="login.jsp"/>
<% }
else
{
%>
<jsp:forward page="success.jsp" >
<jsp:param value="<%=username%>" name="name"/>
<jsp:param value="<%=grade %>" name="ugrade"/>
</jsp:forward>
<% } %>
</form>
</body>
</html>
success.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<%
request.setCharacterEncoding("UTF-8");
String username=request.getParameter("name");
String grade=request.getParameter("ugrade");
String number=request.getParameter("number");
String english=request.getParameter("english");
String checkbox[]=request.getParameterValues("check");
int sum=0;
if(number.equals("four"))
{
sum=2;
}
else sum=0;
if(english.equals("C"))
{
sum=sum+2;
}
else sum=sum+0;
for(int i=0;i<checkbox.length;i++)
{
if(checkbox[i].equals("select"))
sum=sum+1;
else
if(checkbox[i].equals("choose"))
sum=sum+1;
else
sum=sum+0;
}
out.print(username);
out.print(grade);
out.print(number);%>
<p>
<%out.print(english); %>
<p>
<%for(int i=0;i<checkbox.length;i++)
{
out.print(checkbox[i]);
} %>
<p>
<%out.print("标准答案：一：four；二：C；三：choose，select；"); %>
<p>
<%out.print("总分是："+sum); %>
</body>
</html>
错误是：
farward 标签错误，如果去掉与此相关的内容，可以运行成功。
看了好久不知道farward 错在哪了
HTTP Status 500 – Internal Server Error
Type Exception Report
Message An exception occurred processing [/select.jsp] at line [40]
Description The server encountered an unexpected condition that prevented it from fulfilling the request.
Exception
org.apache.jasper.JasperException: An exception occurred processing [/select.jsp] at line [40]
37: else
38: {
39: %>
40: <jsp:include page="success.jsp" >
41: <jsp:param value="<%=username%>" name="name"/>
42: <jsp:param value="<%=grade %>" name="ugrade"/>
43: </jsp:include>
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:617)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:499)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:386)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:330)
javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
Root Cause
org.apache.jasper.JasperException: An exception occurred processing [/success.jsp] at line [19]
16: String english=request.getParameter("english");
17: String checkbox[]=request.getParameterValues("check");
18: int sum=0;
19: if(number.equals("four"))
20: {
21: sum=2;
22: }
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:617)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:514)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:386)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:330)
javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
org.apache.jasper.runtime.JspRuntimeLibrary.include(JspRuntimeLibrary.java:868)
org.apache.jsp.select_jsp._jspService(select_jsp.java:158)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:476)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:386)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:330)
javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
Root Cause
java.lang.NullPointerException
org.apache.jsp.success_jsp._jspService(success_jsp.java:126)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:476)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:386)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:330)
javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
org.apache.jasper.runtime.JspRuntimeLibrary.include(JspRuntimeLibrary.java:868)
org.apache.jsp.select_jsp._jspService(select_jsp.java:158)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:476)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:386)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:330)
javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
Note The full stack trace of the root cause is available in the server logs.
username==""
这句不会成了的，应该用字符串的 equals 才对。
<jsp:forward page="login.jsp"/>
这个标签没有闭合