我想知道如何在 2 个 servlet 之间传递参数。但它有点不同......让我更具体。我有一个登录页面和数据库中的用户及其密码。如果管理员创建的用户没有密码。用户只输入用户名并单击登录，然后会出现创建密码页面。然后刚刚创建密码的用户将自动登录成功。（事情就是这样。我不希望用户重新输入他的用户名和密码“刚刚创建”再次登录。）当他完成创建密码时，他可以被重定向到所需的页面。但是 pageforwards servlet 是第一个 servlet。让我更清楚。
我的 servlet 是 LoginServlet（从 loginPage.jsp 执行）、CreatePassServlet（从 createPass.jsp 执行）。
当用户输入他的用户名 LoginServlet 检查他的密码（它是否存在）然后如果不使用用户名将其转发到 createPass.jsp 页面然后用户输入他的密码然后 CreatePassServlet 创建他的密码并存储在数据库中然后返回他的用户名和密码LoginServlet 的信息（将他引导到所需的页面）
我的课在这里...
登录Servlet
public class LoginServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public LoginServlet() {
super();
}
protected void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {
try {
int pEmployeeId;
String pName;
String pSurname;
String pUserName;
String pUserType;
String query;
String home = "/login.jsp";
String username = request.getParameter("username");
String password = request.getParameter("password");
RequestDispatcher rd = request.getRequestDispatcher(home);
mysqlCon con = new mysqlCon();
LoginService ls = new LoginService();
if((password==null) || (password=="")){
Statement stmt = con.getConnection().createStatement();
query = "SELECT password FROM employee WHERE username='"
+ username + "';";
stmt.executeQuery(query);
ResultSet rs = stmt.getResultSet();
if(rs.next()){
String nextJSP = "createPassword.jsp";
rd = request.getRequestDispatcher(nextJSP);
rd.forward(request, response);
return;
}
}
String getHashedPass = Md5HashPassword.Md5(password);
Statement stmt = con.getConnection().createStatement();
query = "SELECT employee_id, name, surname, usertype, username FROM employee WHERE username='"
+ username + "' AND password='" + getHashedPass + "';";
stmt.executeQuery(query);
ResultSet rs = stmt.getResultSet();
if (rs.next()) {
pEmployeeId = rs.getInt(1);
pName = rs.getString(2);
pSurname = rs.getString(3);
pUserType = rs.getString(4);
pUserName = rs.getString(5);
if (ls.loginCheck(username, getHashedPass) != false) {
Person tmp = new Person();
tmp.setName(pName);
tmp.setSurname(pSurname);
tmp.setType(pUserType);
tmp.setUsername(pUserName);
tmp.setId((long) pEmployeeId);
HttpSession session = request.getSession();
session.setAttribute("person", tmp);
if (pUserType.equals(UserType.MANAGER.toString())) {
String nextJSP = "managerHome.jsp";
rd = request.getRequestDispatcher(nextJSP);
rd.forward(request, response);
}
else if (pUserType.equals(UserType.ADMIN.toString())) {
String nextJSP = "adminHome.jsp";
rd = request.getRequestDispatcher(nextJSP);
rd.forward(request, response);
}
else if (pUserType.equals(UserType.USER.toString())) {
String nextJSP = "userHome.jsp";
rd = request.getRequestDispatcher(nextJSP);
rd.forward(request, response);
} else {
String nextJSP = "login.jsp";
rd = request.getRequestDispatcher(nextJSP);
rd.forward(request, response);
}
}
} else {
request.setAttribute("errorMessage",
"Login Failed. Your username or password is incorrect. ");
rd.forward(request, response);
}
con.getConnection().close();
} catch (InstantiationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
}
}
创建PassServlet...
public class CreatePassServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public CreatePassServlet() {
super();
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
mysqlCon con=new mysqlCon();
String password=request.getParameter("password");
String passwordcheck=request.getParameter("passwordcheck");
if(password.equals(passwordcheck)){
try {
String query;
String hashedPass = Md5HashPassword.Md5(password);
String username=request.getParameter("username");
Statement stmt = con.getConnection().createStatement();
query = "UPDATE employee SET password='"+ hashedPass +"' WHERE username='"+ username +"';";
stmt.executeUpdate(query);
request.setAttribute("username", username);
ServletContext sc = getServletContext();
RequestDispatcher rd = sc.getRequestDispatcher("/LoginServlet");
rd.forward(request, response);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
else{
RequestDispatcher rd=request.getRequestDispatcher("createPassword.jsp");
request.setAttribute("errorMessage",
"Creation failed. Your passwords did not match, please try again. ");
rd.forward(request, response);
}
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
}
}
页面是正确的......当我运行它时我得到了这个......
当我尝试支持 loginservlet 以继续时，CreatePassServlet 将用户名重定向为 NULL 和我的密码。我想关键是我不能再次将我的用户名传回 LoginServlet。然后我从 loginServlet 收到登录用户名 - 密码错误错误，因为用户名是 NULL。
请帮帮我。提前致谢...