Servlet:
package com.CourseExercise.tickets.Service;import java.io.IOException;
import java.sql.SQLException;import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.CourseExercise.tickets.Dao.UserDao;
import com.CourseExercise.tickets.DaoImpl.UserDaoImpl;
import com.CourseExercise.tickets.Model.User; public class UpdateUser extends HttpServlet{
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
UserDao userDao=new UserDaoImpl();
User user=new User();
String username=new String(request.getParameter("username").getBytes("ISO-8859-1"),"UTF-8");
String password=request.getParameter("password");
String email_telephone=request.getParameter("email/telephone");
user.setUsername(username);
user.setPassword(password);
user.setEmail_telephone(email_telephone);
try {
userDao.update(user); } catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { doGet(request, response);
} }
页面调用时出现HTTP Status 500 - --------------------------------------------------------------------------------type Exception reportmessage description The server encountered an internal error () that prevented it from fulfilling this request.exception java.lang.NullPointerException
com.CourseExercise.tickets.Service.UpdateUser.doGet(UpdateUser.java:26)
com.CourseExercise.tickets.Service.UpdateUser.doPost(UpdateUser.java:49)
javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.26 logs.
--------------------------------------------------------------------------------应该怎么解决!
package com.CourseExercise.tickets.Service;import java.io.IOException;
import java.sql.SQLException;import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.CourseExercise.tickets.Dao.UserDao;
import com.CourseExercise.tickets.DaoImpl.UserDaoImpl;
import com.CourseExercise.tickets.Model.User; public class UpdateUser extends HttpServlet{
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
UserDao userDao=new UserDaoImpl();
User user=new User();
String username=new String(request.getParameter("username").getBytes("ISO-8859-1"),"UTF-8");
String password=request.getParameter("password");
String email_telephone=request.getParameter("email/telephone");
user.setUsername(username);
user.setPassword(password);
user.setEmail_telephone(email_telephone);
try {
userDao.update(user); } catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { doGet(request, response);
} }
页面调用时出现HTTP Status 500 - --------------------------------------------------------------------------------type Exception reportmessage description The server encountered an internal error () that prevented it from fulfilling this request.exception java.lang.NullPointerException
com.CourseExercise.tickets.Service.UpdateUser.doGet(UpdateUser.java:26)
com.CourseExercise.tickets.Service.UpdateUser.doPost(UpdateUser.java:49)
javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.26 logs.
--------------------------------------------------------------------------------应该怎么解决!
UpdateUser.java:26
request.getParameter("username")可能得到的是null
调用getBytes("ISO-8859-1")方法而抛出空指针
你查查参数的获取!!!
26行是这行
<% String username=session.getAttribute("username").toString();%>
<form action="updateUser" method=post>
<table>
username:<%=username %><br>
<tr>
<td>
email/telephone: <input type="text" name="email_telephone"/>
</td>
</tr>
<tr>
<td>
password: <input type="password" name="password"/>
</td>
</tr>
<tr>
<td>
<input type=submit value="edit">
</td>
</tr>
</table>
</form> </body>
<INPUT type=hidden name=username value="<%username%>">
-------
name没有传过去。。