如何將表單字段值作爲會話從jsp發送到servlet

我已經創建了醫院管理項目..我想將表單字段值從jsp發送到servlet作爲會話...我嘗試了以下代碼如何將表單字段值作爲會話從jsp發送到servlet

Jsp頁面：

<html> 
<head> 
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 
    <title>Add patient details</title> 
</head> 
<body> 


    <form action="Patientdetails" method="GET"> 


     <fieldset> 
      <legend> <h1> Patient details </h1> </legend> 


      <center> 
       <table> <tr><td> 


          Patient's name: </td><td> <input type="text" name="name" placeholder="Enter the patients's name" value="deeban" pattern='[A-Za-z0-9]{5,15}' title="Doctor name should be minimum of 5 characters and maximum of 15 characters"/> </td></tr><tr><td><br></td></tr><tr><td> 

          Patient's age: </td><td> <input type="text" name = "age" placeholder="Enter the patients's age" pattern='[0-9]{2}' title="Enter age as two digit number"/> </td></tr><tr><td><br></td></tr><tr><td>     

          Gender : </td><td> <label for='male'>male</label> <input type="radio" name = "gender" id='gender' value='male' checked /> 
          <label for ='female'>female</label><input type='radio' name = "gender" id='gender' value='female' /> </td></tr><tr><td><br></td></tr><tr><td> 
          Category of doctor to meet: </td><td><select name="cat"> 
           <optgroup label="Select Category"> 
            <option value="Dentist"> Dentist</option> 
            <option value="Cardiologist"> Cardiologist </option> 
            <option value="surgeon" selected>surgeon </option> 
            <option value="Diabetologists"> Diabetologists‎</option> 
           </optgroup> </select> </td></tr><tr><td><br></td></tr><tr><td> 
          Visiting time: </td><td><select name= "time" multiple> 
           <optgroup label="Available timings"> 
            <option value="9:00A.M-12:00P.M (Morning)"> 9:00A.M-12:00P.M (Morning)</option> 
            <option value="12:00P.M-3:00P.M (Afternoon)">12:00P.M-3:00P.M (Afternoon)</option> 
            <option value="04:00P.M-7:00P.M (Evening)" selected>04:00P.M-7:00P.M (Evening)</option> 
            <option value="8:00P.M-12:00A.M (Night)">8:00P.M-12:00A.M (Night)</option> 
           </optgroup> </select> </td></tr><tr><td> <br></td></tr><tr><td> 

          Your token number:</td><td> <input type="text" name="token" value="14" readonly/>        
         </td></tr><tr><td><br></td></tr><tr><td> 

          <input type='submit' value='submit'> </td></tr> 

        <% 

         try { 
          String name, age, gender, cat, time, token; 
          name = (String) request.getAttribute("name"); 
          age = request.getParameter("age"); 
          gender = request.getParameter("gender"); 
          cat = request.getParameter("cat"); 
          time = request.getParameter("time"); 
          token = request.getParameter("token"); 

          request.getSession().setAttribute("name", name); 
          request.getSession(true).setAttribute("name", name); // firstway 

          session.setAttribute("name", name); //another way 
          session.setAttribute("age", age); 
          session.setAttribute("gender", gender); 
          session.setAttribute("cat", cat); 
          session.setAttribute("time", time); 
          session.setAttribute("token", token); 
          out.println("Session " + request.getSession().getAttribute("name").toString()); 
         } catch (Exception e) { 
          out.println("The exception part is " + e); 
         } 

        %> 

       </table> 
      </center> 

     </fieldset> 
    </form> 
</body>

servlet頁面：

package Patientdetails; 

import java.io.IOException; 
import java.io.PrintWriter; 
import java.util.Enumeration; 
import javax.jms.Session; 
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 Patientdetails extends HttpServlet { 

HttpServletRequest request; 
String[] pname = {"name", "age", "gender", "cat", "time", "token"}; 
String[] pvalue = new String[6]; 

protected void processRequest(HttpServletRequest request, HttpServletResponse response) 
     throws ServletException, IOException { 
    response.setContentType("text/html;charset=UTF-8"); 
    PrintWriter out = response.getWriter(); 
    try { 
     out.println("<!DOCTYPE html>"); 
     out.println("<html>"); 
     out.println("<head>"); 
     // out.println("<title>"+session.getAttribute("name")+"</title>");    
     out.println("</head>"); 
     out.println("<body>"); 


    } finally { 
     out.close(); 
    } 
} 

@Override 
public void init() { 

} 

@Override 
public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { 

    PrintWriter out = response.getWriter(); 


    try { 
     for (int i = 0; i < pname.length; i++) { 
      pvalue[i] = (String) request.getSession().getAttribute(pname[i]); 


     } 



     out.println("<table BORDER ='2'><th>Patient Name</th><th>Patient Age</th><th>Gender</th><th>Category of doctor </th><th>Appointment Time</th><th>Token no</th>"); 

     out.println("<tr><td>" + pvalue[0] + "</td> <td>" + pvalue[1] + "</td><td>" + pvalue[2] + "</td><td>" + pvalue[3] + " </td><td> " + pvalue[4] + " </td><td> " + pvalue[5] + "</td></tr>"); 
      out.println("<h1>The Session value is " + request.getSession().getAttribute("name")+"</h1>"); 
     out.println("</body>"); 
     out.println("</html>"); 
    } catch (Exception e) { 
     out.println("Exception part " + e); 
     e.printStackTrace(out); 
    } 
} 

@Override 
public void destroy() { 
}

}

當我嘗試這樣，Iam只是在Servlet頁面中獲得空值..我不知道它爲什麼只是傳遞空值有沒有其他的方法來傳遞值作爲會議？

來源

2014-08-27 deeban

您需要清楚地知道哪些代碼正在瀏覽器中執行客戶端，哪些正在執行服務器端。在JSP中執行scriptlet代碼時，您的HTML表單尚未提交，因此request或session對象中沒有存儲任何表單值。這就是表單字段值爲null的原因。

您應該移動代碼以將提交表單中的字段值檢索到servlet，因爲這是表單提交到的地方（如其action屬性所指定的那樣）。爲了從你的servlet中獲取表單值，你可以使用：

String paramValue = request.getParameter("paramName");

爲了取回HTTP會話的值，使用：

request.getSession().getAttribute("attributeName");

你通常不會從檢索參數值要求將它們存儲在會話中。使JSP會話作用域更清晰。另外，請注意，如果HTML表單不能安全地多次提交（通常是因爲它正在改變一些服務器端狀態），那麼您的HTML表單應該使用HTTP POST方法而不是GET。

來源

2014-08-27 10:57:18

爲什麼session.getAttribute（「paramname」）不起作用？ – deeban 2014-08-27 10:59:58

但是，getValue（）方法已被棄用。它也返回null ... – deeban 2014-08-27 11:00:52

對不起，我的意思是'getAttribute;' – 2014-08-27 11:04:56

如何將表單字段值作爲會話從jsp發送到servlet

回答

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