自己编写的页面登录出错HTTP Status 500 -
。 - ITeye问答
错误信息：
HTTP Status 500 -
--------------------------------------------------------------------------------
type Exception report
description The server encountered an internal error () that prevented it from fulfilling this request.
java.lang.NullPointerException
com.javasky.dao.UserDao.select(UserDao.java:113)
com.javasky.service.UserService.login(UserService.java:45)
com.javasky.servlet.user.LoginServlet.execute(LoginServlet.java:35)
com.javasky.servlet.user.LoginServlet.doPost(LoginServlet.java:24)
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/6.0.18 logs.
--------------------------------------------------------------------------------
Apache Tomcat/6.0.18
最近在编写一个登录页面，在填写完账号和密码后，点击登录总是出现上面的错误，不知道是怎么回事，希望大虾们帮助一下。
涉及到的代码文件，我会上传上去。UserDao.java中主要实现的是用户操作，UserService.java实现的是用户登录时的逻辑判断，LoginServlet.java实现的是调用UserService.java并返回登录成功或不成功时的页面。前台页面编写用的是jsp，数据库用的是mysql。
UserDao.java代码
package com.javasky.
import java.util.L
import java.util.ArrayL
import com.javasky.pojo.U
import com.javasky.jndi.IDataS
import com.javasky.jndi.JNDIDataS
import com.javasky.tool.DBE
import com.javasky.tool.ToolU
import java.sql.C
import java.sql.PreparedS
import java.sql.ResultS
import java.sql.SQLE
import java.sql.D
public class UserDao implements IUserDao
private IDataSource getDs()
return new JNDIDataSource();
//将一个用户对象修改数据库
public int edit(User user)
IDataSource ds=getDs();
Connection conn=
PreparedStatement pstmt=
String sql=" insert into users(userName,userPassword,userGender,userEmail,userBirthday,userCode) " +
" values(?,?,?,?,?,?) ";
if (user.getId()!=0)
sql=" update users set userName=?,userPassword=?,userGender=?,userEmail=?userBirthday=?,userCode=?" +
" where id=? ";
conn=ds.getConnection();
pstmt=conn.prepareStatement(sql);
pstmt.setString(1,user.getUserName());
pstmt.setString(2,user.getUserPassword());
pstmt.setString(3,user.getUserGender());
pstmt.setString(4,user.getUserEmail());
pstmt.setDate(5,new java.sql.Date(user.getUserBirthday().getTime()));
pstmt.setString(6,user.getUserCode());
if (user.getId()!=0)
pstmt.setInt(7,user.getId());
i=pstmt.executeUpdate();
catch (SQLException e)
e.printStackTrace();
throw new DBException();
ds.closeAll(conn,pstmt,null);
catch (SQLException e)
e.printStackTrace();
//删除一条记录
public int delete(int id)
IDataSource ds=getDs();
Connection conn=
PreparedStatement pstmt=
String sql="delete from users where id=?";
conn=ds.getConnection();
pstmt=conn.prepareStatement(sql);
pstmt.setInt(1,i);
i=pstmt.executeUpdate();
catch (SQLException e)
e.printStackTrace();
throw new DBException();
ds.closeAll(conn,pstmt,null);
catch (SQLException e)
e.printStackTrace();
//根据用户名查询整个用户
public User select(String userName)
User user=
IDataSource ds=getDs();
Connection conn=
PreparedStatement pstmt=
ResultSet rs=
String sql=" select * from users where userName=? ";
conn=ds.getConnection();
pstmt=conn.prepareStatement(sql);
pstmt.setString(1,userName);
rs=pstmt.executeQuery();
if (rs.next())
user=new User();
ToolUtil.copyResultSet(user,rs);
catch (SQLException e)
e.printStackTrace();
throw new DBException();
ds.closeAll(conn,pstmt,rs);
catch (SQLException e)
e.printStackTrace();
//根据id查询用户信息
public User select(int id)
User user=
IDataSource ds=getDs();
Connection conn=
PreparedStatement pstmt=
ResultSet rs=
String sql=" select * from users where id=? ";
conn=ds.getConnection();
pstmt=conn.prepareStatement(sql);
pstmt.setInt(1,id);
rs=pstmt.executeQuery();
if (rs.next())
user=new User();
ToolUtil.copyResultSet(user,rs);
catch (SQLException e)
e.printStackTrace();
throw new DBException();
ds.closeAll(conn,pstmt,rs);
catch (SQLException e)
e.printStackTrace();
//查询所有
public List&User& select()
List&User& userList=new ArrayList&User&();
IDataSource ds=getDs();
Connection conn=
PreparedStatement pstmt=
ResultSet rs=
String sql=" select * from users ";
conn=ds.getConnection();
pstmt=conn.prepareStatement(sql);
rs=pstmt.executeQuery();
while (rs.next())
User user=new User();
ToolUtil.copyResultSet(user,rs);
userList.add(user);
catch (SQLException e)
e.printStackTrace();
throw new DBException();
ds.closeAll(conn,pstmt,rs);
catch (SQLException e)
e.printStackTrace();
return userL
}
UserService.java代码
package com.javasky.
import java.util.M
import java.util.HashM
import javax.servlet.http.HttpServletR
import javax.servlet.http.HttpS
import com.javasky.dao.IUserD
import com.javasky.dao.UserD
import com.javasky.pojo.U
import com.javasky.tool.ToolU
public class UserService
public IUserDao getUserDao()
return new UserDao();
public boolean login(HttpServletRequest request)
boolean flag=
//获得页面输入的信息
String userName=request.getParameter("userName");
String userPassword=request.getParameter("userPassword");
//验证是否为空，如果为空则直接返回
Map&String,String& errorMessage=new HashMap&String,String&();
if (ToolUtil.isEmpty(userName))
errorMessage.put("userName","不能为空");
if (ToolUtil.isEmpty(userPassword))
errorMessage.put("userPassword","不能为空");
if (errorMessage.size()&0)
request.setAttribute("errorMessage",errorMessage);
HttpSession session=request.getSession();
//访问数据库
IUserDao userDao=getUserDao();
User user=userDao.select(userName);
if (null!=user)
if (user.getUserPassword().equals(userPassword))
//成功登陆
session.setAttribute("loginUser",user);
//不是成功登陆
errorMessage.put("userName","用户名或密码错误！！");
request.setAttribute("userName",userName);
request.setAttribute("errorMessage",errorMessage);
}
LoginServlet.java代码
package com.javasky.servlet.
import java.io.IOE
import javax.servlet.http.HttpS
import javax.servlet.http.HttpServletR
import javax.servlet.http.HttpServletR
import javax.servlet.ServletE
import javax.servlet.RequestD
import com.javasky.service.UserS
public class LoginServlet extends HttpServlet
protected void doGet(HttpServletRequest req,HttpServletResponse resp)
throws ServletException,IOException
execute(req,resp);
protected void doPost(HttpServletRequest req,HttpServletResponse resp)
throws ServletException,IOException
execute(req,resp);
protected void execute(HttpServletRequest request,HttpServletResponse response)
throws ServletException,IOException
request.setCharacterEncoding("GBK");
response.setContentType("text/charset=gbk");
//调用userService来为我们提供逻辑判断服务
UserService userService=new UserService();
RequestDispatcher dispatcher=request.getRequestDispatcher("/login.jsp");
if (userService.login(request))
dispatcher=request.getRequestDispatcher("/main.jsp");
dispatcher.forward(request,response);
}
WEB-INF下的web.xml代码
&?xml version="1.0" encoding="GBK"?&
&web-app version="2.5"
xmlns="/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="/xml/ns/javaee
/xml/ns/javaee/web-app_2_5.xsd"&
&welcome-file-list&
&welcome-file&login.jsp&/welcome-file&
&/welcome-file-list&
&!-- 登陆 login --&
&servlet-name&login&/servlet-name&
&servlet-class&com.javasky.servlet.user.LoginServlet&/servlet-class&
&/servlet&
&servlet-mapping&
&servlet-name&login&/servlet-name&
&url-pattern&/login&/url-pattern&
&/servlet-mapping&
&!-- 退出logOut --&
&servlet-name&logOut&/servlet-name&
&servlet-class&com.javasky.servlet.user.LogOutServlet&/servlet-class&
&/servlet&
&servlet-mapping&
&servlet-name&logOut&/servlet-name&
&url-pattern&/logOut&/url-pattern&
&/servlet-mapping&
&!-- 图书管理bookServlet --&
&servlet-name&bookServlet&/servlet-name&
&servlet-class&com.javasky.servlet.book.BookServlet&/servlet-class&
&/servlet&
&servlet-mapping&
&servlet-name&bookServlet&/servlet-name&
&url-pattern&/bookServlet&/url-pattern&
&/servlet-mapping&
&/web-app&
META-INF下的Context.xml代码
&?xml version=""1.0 encoding="GBK"?&
name="jdbc/bookstore"
type="javax.sql.DataSource"
maxActive="10"
maxIdle="2"
maxWait="10000"
username="root"
password=""
driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost:3306/bookstore?autoReconnect=true"
&&/Resource&
&/Context&
问题补充：错误信息：
HTTP Status 500 -
--------------------------------------------------------------------------------
type Exception report
description The server encountered an internal error () that prevented it from fulfilling this request.
java.lang.NullPointerException
com.javasky.dao.UserDao.select(UserDao.java:113)
com.javasky.service.UserService.login(UserService.java:45)
com.javasky.servlet.user.LoginServlet.execute(LoginServlet.java:35)
com.javasky.servlet.user.LoginServlet.doPost(LoginServlet.java:24)
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/6.0.18 logs.
--------------------------------------------------------------------------------
Apache Tomcat/6.0.18
最近在编写一个登录页面，在填写完账号和密码后，点击登录总是出现上面的错误，不知道是怎么回事，希望大虾们帮助一下。
涉及到的代码文件，我会上传上去。UserDao.java中主要实现的是用户操作，UserService.java实现的是用户登录时的逻辑判断，LoginServlet.java实现的是调用UserService.java并返回登录成功或不成功时的页面。前台页面编写用的是jsp，数据库用的是mysql。
UserDao.java代码
package com.javasky.
import java.util.L
import java.util.ArrayL
import com.javasky.pojo.U
import com.javasky.jndi.IDataS
import com.javasky.jndi.JNDIDataS
import com.javasky.tool.DBE
import com.javasky.tool.ToolU
import java.sql.C
import java.sql.PreparedS
import java.sql.ResultS
import java.sql.SQLE
import java.sql.D
public class UserDao implements IUserDao
private IDataSource getDs()
return new JNDIDataSource();
//将一个用户对象修改数据库
public int edit(User user)
IDataSource ds=getDs();
Connection conn=
PreparedStatement pstmt=
String sql=" insert into users(userName,userPassword,userGender,userEmail,userBirthday,userCode) " +
" values(?,?,?,?,?,?) ";
if (user.getId()!=0)
sql=" update users set userName=?,userPassword=?,userGender=?,userEmail=?userBirthday=?,userCode=?" +
" where id=? ";
conn=ds.getConnection();
pstmt=conn.prepareStatement(sql);
pstmt.setString(1,user.getUserName());
pstmt.setString(2,user.getUserPassword());
pstmt.setString(3,user.getUserGender());
pstmt.setString(4,user.getUserEmail());
pstmt.setDate(5,new java.sql.Date(user.getUserBirthday().getTime()));
pstmt.setString(6,user.getUserCode());
if (user.getId()!=0)
pstmt.setInt(7,user.getId());
i=pstmt.executeUpdate();
catch (SQLException e)
e.printStackTrace();
throw new DBException();
ds.closeAll(conn,pstmt,null);
catch (SQLException e)
e.printStackTrace();
//删除一条记录
public int delete(int id)
IDataSource ds=getDs();
Connection conn=
PreparedStatement pstmt=
String sql="delete from users where id=?";
conn=ds.getConnection();
pstmt=conn.prepareStatement(sql);
pstmt.setInt(1,i);
i=pstmt.executeUpdate();
catch (SQLException e)
e.printStackTrace();
throw new DBException();
ds.closeAll(conn,pstmt,null);
catch (SQLException e)
e.printStackTrace();
//根据用户名查询整个用户
public User select(String userName)
User user=
IDataSource ds=getDs();
Connection conn=
PreparedStatement pstmt=
ResultSet rs=
String sql=" select * from users where userName=? ";
conn=ds.getConnection();
pstmt=conn.prepareStatement(sql);
pstmt.setString(1,userName);
rs=pstmt.executeQuery();
if (rs.next())
user=new User();
ToolUtil.copyResultSet(user,rs);
catch (SQLException e)
e.printStackTrace();
throw new DBException();
ds.closeAll(conn,pstmt,rs);
catch (SQLException e)
e.printStackTrace();
//根据id查询用户信息
public User select(int id)
User user=
IDataSource ds=getDs();
Connection conn=
PreparedStatement pstmt=
ResultSet rs=
String sql=" select * from users where id=? ";
conn=ds.getConnection();
pstmt=conn.prepareStatement(sql);
pstmt.setInt(1,id);
rs=pstmt.executeQuery();
if (rs.next())
user=new User();
ToolUtil.copyResultSet(user,rs);
catch (SQLException e)
e.printStackTrace();
throw new DBException();
ds.closeAll(conn,pstmt,rs);
catch (SQLException e)
e.printStackTrace();
//查询所有
public List&User& select()
List&User& userList=new ArrayList&User&();
IDataSource ds=getDs();
Connection conn=
PreparedStatement pstmt=
ResultSet rs=
String sql=" select * from users ";
conn=ds.getConnection();
pstmt=conn.prepareStatement(sql);
rs=pstmt.executeQuery();
while (rs.next())
User user=new User();
ToolUtil.copyResultSet(user,rs);
userList.add(user);
catch (SQLException e)
e.printStackTrace();
throw new DBException();
ds.closeAll(conn,pstmt,rs);
catch (SQLException e)
e.printStackTrace();
return userL
}
UserService.java代码
package com.javasky.
import java.util.M
import java.util.HashM
import javax.servlet.http.HttpServletR
import javax.servlet.http.HttpS
import com.javasky.dao.IUserD
import com.javasky.dao.UserD
import com.javasky.pojo.U
import com.javasky.tool.ToolU
public class UserService
public IUserDao getUserDao()
return new UserDao();
public boolean login(HttpServletRequest request)
boolean flag=
//获得页面输入的信息
String userName=request.getParameter("userName");
String userPassword=request.getParameter("userPassword");
//验证是否为空，如果为空则直接返回
Map&String,String& errorMessage=new HashMap&String,String&();
if (ToolUtil.isEmpty(userName))
errorMessage.put("userName","不能为空");
if (ToolUtil.isEmpty(userPassword))
errorMessage.put("userPassword","不能为空");
if (errorMessage.size()&0)
request.setAttribute("errorMessage",errorMessage);
HttpSession session=request.getSession();
//访问数据库
IUserDao userDao=getUserDao();
User user=userDao.select(userName);
if (null!=user)
if (user.getUserPassword().equals(userPassword))
//成功登陆
session.setAttribute("loginUser",user);
//不是成功登陆
errorMessage.put("userName","用户名或密码错误！！");
request.setAttribute("userName",userName);
request.setAttribute("errorMessage",errorMessage);
}
LoginServlet.java代码
package com.javasky.servlet.
import java.io.IOE
import javax.servlet.http.HttpS
import javax.servlet.http.HttpServletR
import javax.servlet.http.HttpServletR
import javax.servlet.ServletE
import javax.servlet.RequestD
import com.javasky.service.UserS
public class LoginServlet extends HttpServlet
protected void doGet(HttpServletRequest req,HttpServletResponse resp)
throws ServletException,IOException
execute(req,resp);
protected void doPost(HttpServletRequest req,HttpServletResponse resp)
throws ServletException,IOException
execute(req,resp);
protected void execute(HttpServletRequest request,HttpServletResponse response)
throws ServletException,IOException
request.setCharacterEncoding("GBK");
response.setContentType("text/charset=gbk");
//调用userService来为我们提供逻辑判断服务
UserService userService=new UserService();
RequestDispatcher dispatcher=request.getRequestDispatcher("/login.jsp");
if (userService.login(request))
dispatcher=request.getRequestDispatcher("/main.jsp");
dispatcher.forward(request,response);
}
WEB-INF下的web.xml代码
&?xml version="1.0" encoding="GBK"?&
&web-app version="2.5"
xmlns="/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="/xml/ns/javaee
/xml/ns/javaee/web-app_2_5.xsd"&
&welcome-file-list&
&welcome-file&login.jsp&/welcome-file&
&/welcome-file-list&
&!-- 登陆 login --&
&servlet-name&login&/servlet-name&
&servlet-class&com.javasky.servlet.user.LoginServlet&/servlet-class&
&/servlet&
&servlet-mapping&
&servlet-name&login&/servlet-name&
&url-pattern&/login&/url-pattern&
&/servlet-mapping&
&!-- 退出logOut --&
&servlet-name&logOut&/servlet-name&
&servlet-class&com.javasky.servlet.user.LogOutServlet&/servlet-class&
&/servlet&
&servlet-mapping&
&servlet-name&logOut&/servlet-name&
&url-pattern&/logOut&/url-pattern&
&/servlet-mapping&
&!-- 图书管理bookServlet --&
&servlet-name&bookServlet&/servlet-name&
&servlet-class&com.javasky.servlet.book.BookServlet&/servlet-class&
&/servlet&
&servlet-mapping&
&servlet-name&bookServlet&/servlet-name&
&url-pattern&/bookServlet&/url-pattern&
&/servlet-mapping&
&/web-app&
META-INF下的Context.xml代码
&?xml version=""1.0 encoding="GBK"?&
name="jdbc/bookstore"
type="javax.sql.DataSource"
maxActive="10"
maxIdle="2"
maxWait="10000"
username="root"
password=""
driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost:3306/bookstore?autoReconnect=true"
&&/Resource&
&/Context&
下载次数: 2
根据报的错自己找错误吧，多试试，这个错误不是很难。
java.lang.NullPointerException这个是报的空指针异常，也就是说你想要用的值或获取到的值是空的
com.javasky.dao.UserDao.select(UserDao.java:113)这个说明你是在哪里错误的，你可能是这出错了，出错的原因可能是没获取到值或者获取到得值是空的，根据提示去找问题，相信你会坚决的，祝楼主早日解决。
是你的jndi数据源 没有获取到 导致连接对象conn为null
java.lang.NullPointerException
报的是空指针异常
你检查一下你接受到的参数是不是空的，或者是否接收到了
已解决问题
未解决问题192.168.1.1登陆页面是电信登陆页面的解决办法 - 192路由网
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本帖子已过去太久远了，不再提供回复功能。请问这个简单的登录界面为什么跳转老错，就是登录账户和密码都对的还跳转不到指定页面？ - ITeye问答
代码：
/////////////////////////////////////////
LoginServlet.java
import java.io.IOE
import java.io.PrintW
import java.util.ArrayL
import javax.servlet.ServletE
import javax.servlet.http.HttpS
import javax.servlet.http.HttpServletR
import javax.servlet.http.HttpServletR
import javax.servlet.http.HttpS
public class LoginServlet extends HttpServlet {
public void init() throws ServletException {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
doPost(request,response);
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
//从请求中取出用户名和密码的值
String username = request.getParameter("username");
String password = request.getParameter("password");
//生成一个ArrayList对象,并把用户名和密码的值存入该对象中.
ArrayList arr = new ArrayList();
arr.add(username);
arr.add(password);
//生成一个session对象
&&&&&&&& HttpSession session = request.getSession(true);
&&&&&&&& session.removeAttribute("username");
&&&&&&&& session.setAttribute("usrename", username);
&&&&&&&&
&&&&&&&& //调用模型组件loginHandler,检查该用户是checkLogin否已经注册
&&&&&&&& LoginHandler login = new LoginHandler();
&&&&&&&&
boolean mark = login.checkLogin(arr);
response.sendRedirect("main.jsp");
else response.sendRedirect("register.jsp");
} catch (Exception e) {
e.printStackTrace();
&&&&&&&&&&&&
public LoginServlet() {
public void destroy() {
super.destroy();
}
///////////////////////////////////////////
LoginHandler.java
import java.sql.*;
import java.util.*;
class LoginHandler {
public LoginHandler(){}
//检查是否已经注册
public boolean checkLogin(ArrayList arr){
//数据库中访问组件DBPoolZ中取得连接
conn = DBPool.getConnection();
String name = (String)arr.get(0);
String password = (String)arr.get(1);
rs = ps.executeQuery("select * from bbs.t_userinfo where username=? and password=?");
while(rs.next())
if(name.equals(rs.getString("username"))&&password.equals(rs.getString("password"))) {
DBPool.dbClose(conn,ps,rs);
String sql = "select * from bbs.t_userinfo where username=? and password=?";
ps = conn.prepareStatement(sql);
ps.setString(1,name);
ps.setString(2,password);
rs = ps.executeQuery();
if(rs.next()){
DBPool.dbClose(conn,ps,rs);
DBPool.dbClose(conn,ps,rs);
catch(SQLException e){}
////////////////////////////////////////////////////////////////////
DBPool.java
import java.io.*;
import java.sql.*;
import java.util.P
public class DBPool {
&&&&&& private static DBPool instance =
&&&&&&
&&&&&& //取得连接
&&&&&& public static synchronized Connection getConnection(){
&&&
&& if(instance == null){
&&&
&& instance = new DBPool();
&&&
&& return instance._getConnection();
&&&&&& }
&&&&&&
&&&&&& private DBPool(){super();}
&&&&&&
&&&&&& private Connection _getConnection(){
&&&
&& try{
&&&
&& String sDBDriver =
&&&
&& String sConnection =
&&&
&& String sUser =
&&&
&& String sPassword =
&&&
&& Properties p = new Properties();
&&&
&& InputStream is = getClass().getResourceAsStream("/db.properties");
&&&
&& p.load(is);
&&&
&& sDBDriver = p.getProperty("DBDriver",sDBDriver);
&&&
&& sConnection = p.getProperty("Connection", sConnection);
&&&
&& sUser = p.getProperty("User",sUser);
&&&
&& sPassword = p.getProperty("Password",sPassword);
&&&
&& Properties pr = new Properties();
&&&
&& pr.put("user", sUser);
&&&
&& pr.put("password", sPassword);
&&&
&& pr.put("characterEncoding", "GB2312");
&&&
&& pr.put("useUnicode", "TRUE");
&&&
&& Class.forName(sDBDriver);
&&&
&& return DriverManager.getConnection(sConnection,pr);
&&&
&& catch(Exception e){
&&&
&& System.out.println(e);
&&&
&& }
&&&&&& }
&&&&&&
&&&&&& //释放资源
&&&&&& public static void dbClose(Connection conn,PreparedStatement ps,ResultSet rs)
&&&&&& throws SQLException
&&&&&& {
&&&
rs.close();
&&&
ps.close();
&&&
conn.close();
&&&&&& }
}
//////////////////////////////////
db.properties
DBDriver = com.mysql.jdbc.Driver
Connection = jdbc:mysql://localhost:3306/bbs/username=? and password=?
User =
Password =
////////////////////////////
login.jsp
&%@ page language="java" import="java.util.*" pageEncoding="gb2312"%&
&%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%&
&!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"&
&html&
& &head&
&&& &base href="&%=basePath%&"&
&&&
&&& &title&登录页面&/title&
&&&
&meta http-equiv="pragma" content="no-cache"&
&meta http-equiv="cache-control" content="no-cache"&
&meta http-equiv="expires" content="0"&&&&
&meta http-equiv="keywords" content="keyword1,keyword2,keyword3"&
&meta http-equiv="description" content="This is my page"&
&link rel="stylesheet" type="text/css" href="styles.css"&
& &/head&
&
& &body&
&&
&form method ="post" action="loginservlet"&
用户名：&input type="text" name="username" size="15"&&br&&br&
密码:&input type="password" name="password" size="15"&&br&&br&
&input type="submit" name="submit" value="登录"&&br&
&/form&
& &/body&
&/html&
//////////////////////////////////////////////////////
两外两个页面就不写了。
求高手指导指导
问题补充：wenchenyangailiuyan 写道你这个加上path路径试试，重定向好像是相当于上下文路径而言的
在哪里加呢？怎么改。
问题补充：wenchenyangailiuyan 写道response.sendRedirect(" request.getContextPath()\main.jsp");
同理试试
不对。现在报一个错误
The server encountered an internal error () that prevented it from fulfilling this request.
请问这个是什么 错误呢？转都转不过去了。
采纳的答案
response.sendRedirect("main.jsp");
response.sendRedirect("register.jsp");
你的main.jsp，register.jsp是和login.jsp放同一个文件夹里吗？
不行的话，把路径写死试试：
response.sendRedirect("/project_name/xxx/xxx.jsp");
改成这个试试response.sendRedirect(" request.getContextPath()/main.jsp");
能把你的错误贴出来吗
response.sendRedirect(" request.getContextPath()\main.jsp");
你这个加上path路径试试，重定向好像是相当于上下文路径而言的
已解决问题
未解决问题