Question

下面是登录页面：

index.html

    <div class="container " >
    <h2  align="center" >Account Login</h2><br>

    <form action="servlet1" method="post"> 
    <div class="input-group">
        <span class="input-group-addon"><i class="glyphicon glyphicon-user"></i></span>
        <input type="text" class="form-control" name="userName" placeholder="Username">
      </div> <br>
    <div class="input-group">
        <span class="input-group-addon"><i class="glyphicon glyphicon-lock"></i></span>
          <input type="password" class="form-control" name="userPass" placeholder="Password">

        </div>
    <div class="form-group">
    <br> 
    <span id="spanbut"><input type="submit" value="Login" class="btn btn-primary"  /> </span> 
    </div>
    </form>
    </div>

下面是检查用户名和密码是否匹配的servlet。用户名和密码是硬编码的。如果它们匹配，则导航到欢迎页面。

Login.java

    import java.io.*;  
    import javax.servlet.*;  
    import javax.servlet.http.*;  
    import javax.servlet.annotation.WebServlet;  
    @WebServlet("/servlet1")  
    public class Login extends HttpServlet {  

    public void doPost(HttpServletRequest request, HttpServletResponse response)  
            throws ServletException, IOException {  

        response.setContentType("text/html");  
        PrintWriter out = response.getWriter();  

        String n=request.getParameter("userName");  
        String p=request.getParameter("userPass");  

        String[][] arr = new String [4][4];
        arr[0][0] = "ABC";
        arr[0][1] = "Password123";
        arr[1][0] = "XYZ";
        arr[1][1] = "servlet";
        arr[2][0] = "PQR";
        arr[2][1] = "Outlook123";
        arr[3][0] = "TUV";
        arr[3][1] = "Hello123";
        boolean flag=false;

        for (int i = 0; i < arr.length; i++) 
        {
            if(n.equals(arr[i][0]))
            {
                if(p.equals(arr[i][1]))
                {

                    RequestDispatcher rd=request.getRequestDispatcher("/servlet2");  
                    rd.forward(request, response); 
                    flag =true;
                }
            }
        }

        if(flag==false)
        {
            //out.print("Sorry UserName or Password Error!");  
            RequestDispatcher rd=request.getRequestDispatcher("incorrect.html");  
            rd.include(request, response); 
        }  

    }}

我必须通过html将用户名值获取到欢迎页面。以下是被称为欢迎页面的servlet。我需要一个servlet吗？

WelcomeServlet.java

    @WebServlet("/servlet2")
    public class WelcomeServlet extends HttpServlet {  

        public void doPost(HttpServletRequest request, HttpServletResponse response)  
            throws ServletException, IOException {  

        response.setContentType("text/html");  
        PrintWriter out = response.getWriter();  

        String n=request.getParameter("userName");  
        out.print("Welcome "+n);  

        }  

    }

Answer 1

您可以使用 request.getAttribute() 和 request.setAttribute() 来获取username。如下所示：

       if(n.equals(arr[i][0]))
            {
                if(p.equals(arr[i][1]))
                {
                      //get username if password and username matched
                   String username1=a[i][0];
                   //set username1 in request
                    request.setAttribute("username", username1); 
                    RequestDispatcher rd=request.getRequestDispatcher("/servlet2");  
                    rd.forward(request, response); 
                    flag =true;
                }
            }

然后在您的WelcomeServlet中执行以下操作：

public void doPost(HttpServletRequest request, HttpServletResponse response)  
            throws ServletException, IOException {  

        response.setContentType("text/html");  
        PrintWriter out = response.getWriter();  
           //getting value got from Login servlet
        String n=(String)request.getAttribute("username");  
        out.print("Welcome "+n);  

        }

通过servlet进入登录页面后，如何将用户名值带入欢迎页面？

1 个答案: