我有一個servlet中的空指針異常的問題。 如果我不選擇這個複選框並提交表單,那麼我有一個帶複選框的表單a.jsp,然後在a.servlet中發生空指針異常。 我如何處理這個異常
代碼 a.jsp
<table border='0' width='50%' cellspacing='0' cellpadding='0' ><form name=form1 method=post action=aservlet >
<input type=hidden name=todo value=post>
<tr bgcolor='#ffffff'><td align=center >
<font face='verdana' size='2'><b>Sex</b><input type=radio name=sex value='male'>Male </font>
<input type=radio name=sex value='female'><font face='verdana' size='2'>Female</font></td></tr>
<tr><td align=center bgcolor='#f1f1f1'>
<font face='verdana' size='2'><input type=checkbox name=agree >I agree to terms and conditions </font>
</td></tr>
<tr bgcolor='#ffffff'><td align=center >
<input type=submit value=Submit>
<input type=reset value=Reset>
</td></tr>
</form></table>
aservlet.java
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.Statement;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class Admin extends HttpServlet {
public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException,IOException
{
response.setContentType("text/html");
PrintWriter out = response.getWriter();
request.getParameter ("agree");
}}
例外:
例外
顯示java.lang.NullPointerException com.centralvisa.servlets.Admin.doPost(Admin.java:26) javax.servlet.http.HttpServlet.service(HttpServlet.java:637) javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
感謝
請添加一些代碼... – Tobias 2010-10-18 11:20:25
這不是完整的代碼。 – BalusC 2010-10-18 11:32:20