请求界面为选择性别与爱好(多个复选框),为什么当不选择爱好时即len=0时,并没有按jsp文件说写的那样出现文件,而是页面报错,实在不解,请耐心的朋友帮看看这是为什么?<%
String msg = null;
String sex = request.getParameter("sex");
String[] favorites = request.getParameterValues("favorites");
int len = favorites.length;
boolean tag = true;
if(sex == null)
msg = "<font color='red'>请选择性别</font><br>";
else
msg = sex.equals("男") ? "先生你好!" : "女士你好!";
if(len <= 0)
{
msg = msg+"你<font color='red'>无</font>爱好?";
tag = false;
}
msg=msg+"<br>你的爱好有:";
for(int i = 0; i < len; i++)
{
msg = msg + favorites[i] + "、";
}
msg = tag?msg.substring(0,msg.length()-2):msg;
out.print("<br>" + msg + "<br>谢谢参与.");
%>异常信息如下:
type Exception reportmessage description The server encountered an internal error () that prevented it from fulfilling this request.exception org.apache.jasper.JasperException: An exception occurred processing JSP page /ShowChoice.jsp at line 2724: String msg = null;
25: String sex = request.getParameter("sex");
26: String[] favorites = request.getParameterValues("favorites");
27: int len = favorites.length;
28: boolean tag = true;
29: if(sex == null)
30: msg = "<font color='red'>请选择性别</font><br>";
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:505)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:416)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
String msg = null;
String sex = request.getParameter("sex");
String[] favorites = request.getParameterValues("favorites");
int len = favorites.length;
boolean tag = true;
if(sex == null)
msg = "<font color='red'>请选择性别</font><br>";
else
msg = sex.equals("男") ? "先生你好!" : "女士你好!";
if(len <= 0)
{
msg = msg+"你<font color='red'>无</font>爱好?";
tag = false;
}
msg=msg+"<br>你的爱好有:";
for(int i = 0; i < len; i++)
{
msg = msg + favorites[i] + "、";
}
msg = tag?msg.substring(0,msg.length()-2):msg;
out.print("<br>" + msg + "<br>谢谢参与.");
%>异常信息如下:
type Exception reportmessage description The server encountered an internal error () that prevented it from fulfilling this request.exception org.apache.jasper.JasperException: An exception occurred processing JSP page /ShowChoice.jsp at line 2724: String msg = null;
25: String sex = request.getParameter("sex");
26: String[] favorites = request.getParameterValues("favorites");
27: int len = favorites.length;
28: boolean tag = true;
29: if(sex == null)
30: msg = "<font color='red'>请选择性别</font><br>";
Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:505)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:416)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
int len = 0;
if (favorites!=null && favorites.length>0){
len = favorites.length;
}