我正在servlet上工作,当我尝试下面的代码时,它会产生NumberFormatException,我已经初始化了所有变量,但当我单击按钮时,它在变量中分配了null值,这会导致Exeption
public class page1 extends HttpServlet
{
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
int q=0,mq=0,umq=0;
String qno="0";
if(request.getParameter("Bt")!=null)
{
qno=request.getParameter("Bt");
q=Integer.parseInt(qno);
}
if(request.getParameter("markBt")!=null)
{
qno=request.getParameter("markBt");
q=Integer.parseInt(qno);
mq=q;
q++;
}
if(request.getParameter("unmarkBt")!=null)
{
qno=request.getParameter("unmarkBt");
q=Integer.parseInt(qno);
umq=q;
}
if(request.getParameter("saveBt")!=null)
{
qno=request.getParameter("saveBt");
q=Integer.parseInt(qno);
mq=q;
q++;
}
qno=""+q;
try
{
out.println("<script src="myScript.js"></script>");
out.println("<form action="page1" method="POST">");
out.println("<input type="hidden" name="markBt" />");
out.println("<label>");
out.println("<br /><input type="submit" name="button" value="Marks For Review & Next" id="mark" onclick="setColor(b"+qno+",'#fff200');this.form.markBt.value="+qno+";this.form.action='page1?flag=1&act=1';this.form.submit();" />");
out.println("</label>");
out.println("<input type="hidden" name="unmarkBt" />");
out.println("<label>");
out.println(" <input type="submit" name="button" value="Unmarks For Review & Next" id="unmark" onclick="setColor(b"+qno+",'#fff200');this.form.unmarkBt.value="+qno+";this.form.action='page1?flag=1&act=1';this.form.submit();" />");
out.println("</label>");
out.println("<input type="hidden" name="saveBt" />");
out.println("<label>");
out.println(" <input type="reset" value="Clear Response" /> <input type="submit" name="button" value="Save & Next" id="save" onclick="this.form.saveBt.value="+qno+";this.form.action='page1?flag=1&act=1';this.form.submit();" />");
out.println("</label>");
out.println("</form>");
out.println("<h1>qno="+q+"</h1>");
out.println("<h1>qno="+mq+"</h1>");
out.println("<h1>qno="+umq+"</h1>");
out.println("<h1>qno="+qno+"</h1>");
out.println(" </body>");
out.println("</html>");
}
finally
{
}
}
}
如何传递变量的值任何人都能帮忙吗,提前感谢
尝试比较空字符串("),如果不起作用,请为#number格式异常提供堆栈跟踪示例:-!".等于(var)
您应该编写单独的html代码,在jsp中编写html代码,并在servlet中编写逻辑。如果无法获得NumberFormatException。