急。。java.lang.NumberFormatException: null
高手们快救救,我头都弄大了
jsp代码:
<form action="Xggdservlet" name="student">
<table width='680' border='1' cellspacing='0' cellpadding='0' bordercolor='#B8D9F2' align=center >
<%
Studtable st=(Studtable)listVo.get(0);
out.print("<tr>");
out.print("<td align=center><font style='font-size: 12pt'>");
out.print("序号");
out.print("<td align=center><font style='font-size: 12pt'>");
out.print(st.getId());
request.setAttribute("id",st.getId());
out.print("</tr>");
out.print("<tr>");
out.print("<td align=center><font style='font-size: 12pt'>");
out.print("姓名");
out.print("<td align=center><font style='font-size: 12pt'>");
out.print("<input type='text' name='name' value="+st.getName()+">");
out.print("</tr>");
out.print("<tr>");
out.print("<td align=center><font style='font-size: 12pt'>");
out.print("性别");
out.print("<td align=center><font style='font-size: 12pt'>");
out.print("<input type='text' name='sex' value="+st.getSex()+">");
out.print("</tr>");
out.print("<tr>");
out.print("<td align=center><font style='font-size: 12pt'>");
out.print("班级");
out.print("<td align=center><font style='font-size: 12pt'>");
out.print("<input type='text' name='grade' value="+st.getGrade()+">");
out.print("</tr>");
out.print("<tr>");
out.print("<td align=center><font style='font-size: 12pt'>");
out.print("学号");
out.print("<td align=center><font style='font-size: 12pt'>");
out.print("<input type='text' name='cid' value="+st.getCid()+">");
out.print("</tr>");
out.print("<tr>");
out.print("<td align=center><font style='font-size: 12pt'>");
out.print("身份证号码");
out.print("<td align=center><font style='font-size: 12pt'>");
out.print("<input type='text' name='sid' value="+st.getSid()+">");
out.print("</tr>");
%>
<tr>
<td colspan='2' align='center'><font style='font-size: 12pt'>
<input type="submit" name="cdk" value="确定修改"">
</tr>
</table>
</form>
servlet代码:
int id;
String sql="";
boolean b=false;
id=Integer.parseInt((String)request.getAttribute("stid"));
String name=request.getParameter ( "name" );
name=Chinese.toChinese(name);
String sex=request.getParameter ( "sex" );
sex=Chinese.toChinese(sex);
String grade=request.getParameter ( "grade" );
grade=Chinese.toChinese(grade);
String cid=request.getParameter ( "cid" );
String sid=request.getParameter ( "sid" );
sql="update student set name='"+name+"',set sex='"+sex+"',set grade='"+grade+"',set cid='"+cid+"',set sid='"+sid+"' where id='"+id+"'";
try{
b=Database3.executeUpdate(sql);
} catch (Exception e )
{
e.printStackTrace ( );
}
tomcat出错提示:
exception
java.lang.NumberFormatException: null
java.lang.Integer.parseInt(Unknown Source)
java.lang.Integer.parseInt(Unknown Source)
gubo.Xggdservlet.doGet(Xggdservlet.java:21)
javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)