如何从以前的jsp页面检索值到结果页面？

Question

如何从以前的jsp页面检索值到结果页面？

Din*_*mar 0 javascript java jsp servlets

我正在创建一个测验应用程序.这里有5个jsp页面,有5个不同的quizes.如果我使用1个jsp页面和结果页面,它工作得很好...... 它从QuizPage5.jsp重定向并在ResultPage.jsp中显示结果.我需要将QuizPage1.jsp,QuizPage2.jsp,QuizPage3.jsp,QuizPage4.jsp和QuizPage5.jsp的所有结果显示到ResultPage.jsp.

我用了

在jsp1中传递值.

<form action="">
<input type="hidden" name="hidden" value="hidden">
<input type="submit" value="submit"></form>

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在jsp2中获取价值

String value=request.getParameter("hidden");

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但是,我得到了 java.lang.NullPointerException

这是我的代码..

QuizPage1.jsp

<html>  
    <head>  
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">  
            <script language="JavaScript">  

            function check()  
               {  
                   var radio_choice = false;  
                   for (counter = 0; counter < myform.grp.length; counter++)  
                    {  
                        if (myform.grp[counter].checked)  
                        radio_choice = true;  
                    }  
                        if (!radio_choice)  
                         {  
                            alert("Please select one.")  
                            return (false);  
                         }  
                         return(true);  
                     }  
</script>  
    </head>  
   <body> 
        <h3>Quiz No.1</h3>

        Q1.Which one of the following is the Capital of India?<br><br>  
        <form action="QuizPage2.jsp" method="post" name="myform" onsubmit="return check();">  
            <input type="radio" name="grp" value="New Delhi" >New Delhi<br>  
             <input type="radio" name="grp" value="Kolkata" >Kolkata<br>  
                 <input type="radio" name="grp" value="Chennai" >Chennai<br>  
                     <input type="radio" name="grp" value="Mumbai" >Mumbai<br>  
                     <br><br><input type="submit" value="Next Question"> 
                     <input type="hidden" name="hidden" value="grp">
                     <input type="submit" value ="Back" onclick="window.history.back();"/> 

        </form>  
      </body>



</html>

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QuizPage2.jsp

<html>  
    <head>  
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">  
            <script language="JavaScript">  

            function check()  
               {  
                   var radio_choice = false;  
                   for (counter = 0; counter < myform2.grp2.length; counter++)  
                    {  
                        if (myform2.grp2[counter].checked)  
                        radio_choice = true;  
                    }  
                        if (!radio_choice)  
                         {  
                            alert("Please select any one Answer");  
                            return (false);  
                         }  
                         return(true);  
                     }  
</script>  
    </head>  
    <body>  
        <h3>Quiz No.2</h3>

        Q2. Where is Chennai Located?<br><br>  
        <form action="QuizPage3.jsp"method="post" name="myform2" onsubmit="return check();">  
            <input type="radio" name="grp2" value="Karnataka" >Karnataka<br>  
             <input type="radio" name="grp2" value="Tamilnadu" >Tamilnadu<br>  
                 <input type="radio" name="grp2" value="Andhra Pradesh" >Andhra Pradesh<br>  
                     <input type="radio" name="grp2" value="Maharashtra" >Maharashtra<br>  
                     <br><br><input type="submit" value="Next Question">  
                      <input type="hidden" name="hidden" value="grp2">
                     <input type="submit" value ="Back" onclick="window.history.back();"/> 


        </form>  
        <%
            String s1=request.getParameter("grp");
         %>
      </body>  
</html>

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QuizPage3.jsp

<html>  
    <head>  
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">  
            <script language="JavaScript">  

            function check()  
               {  
                   var radio_choice = false;  
                   for (counter = 0; counter < myform3.grp3.length; counter++)  
                    {  
                        if (myform3.grp3[counter].checked)  
                        radio_choice = true;  
                    }  
                        if (!radio_choice)  
                         {  
                            alert("Please select any one Answer");  
                            return (false);  
                         }  
                         return(true);  
                     }  
</script>  
    </head>  
    <body>  
        <h3>Quiz No.3</h3>
        Q3. What is the largest state in the USA<br><br>  
        <form action="QuizPage4.jsp"method="post" name="myform" onsubmit="return check();">  
            <input type="radio" name="grp3" value="New York" >New York<br>  
             <input type="radio" name="grp3" value="Alaska" >Alaska<br>  
                 <input type="radio" name="grp3" value="California" >California<br>  
                     <input type="radio" name="grp3" value="Melbourne" >Melbourne<br>  
                     <br><br><input type="submit" value="Next Question">  
                     <input type="hidden" name="hidden" value="grp3">
                     <input type="submit" value ="Back" onclick="window.history.back();"/> 

        </form>  
        <%
            String s2=request.getParameter("grp2");
         %>
      </body>  
</html>

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QuizPage4.jsp

<html>  
    <head>  
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">  
            <script language="JavaScript">  

            function check()  
               {  
                   var radio_choice = false;  
                   for (counter = 0; counter < myform4.grp4.length; counter++)  
                    {  
                        if (myform4.grp4[counter].checked)  
                        radio_choice = true;  
                    }  
                        if (!radio_choice)  
                         {  
                            alert("Please select any one Answer");  
                            return (false);  
                         }  
                         return(true);  
                     }  
</script>  
    </head>  
    <body>  
        <h3>Quiz No.4</h3>
        Q4. The famous Dilwara Temples are situated in<br><br>  
        <form action="QuizPage5.jsp"method="post" name="myform" onsubmit="return check();">  
            <input type="radio" name="grp4" value="Uttar Pradesh" >Uttar Pradesh<br>  
             <input type="radio" name="grp4" value="Maharashtra" >Maharashtra<br>  
                 <input type="radio" name="grp4" value="Andhra Pradesh" >Andhra Pradesh<br>  
                     <input type="radio" name="grp4" value="Rajasthan" >Rajasthan<br>  
                     <br><br><input type="submit" value="Next Question"> 
                     <input type="hidden" name="hidden" value="grp4">
                     <input type="submit" value ="Back" onclick="window.history.back();"/> 

        </form> 
        <%
            String s3=request.getParameter("grp3");
         %>
      </body>  
</html>

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QuizPage5.jsp

<html>  
    <head>  
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">  
            <script language="JavaScript">  

            function check()  
               {  
                   var radio_choice = false;  
                   for (counter = 0; counter < myform5.grp5.length; counter++)  
                    {  
                        if (myform5.grp5[counter].checked)  
                        radio_choice = true;  
                    }  
                        if (!radio_choice)  
                         {  
                            alert("Please select any one Answer");  
                            return (false);  
                         }  
                         return(true);  
                     }  
</script>  
    </head>  
    <body>  
        <h3>Quiz No.5</h3>
        Q5. The Indian Institute of Science is located at<br><br>  
        <form action="ResultPage.jsp"method="post" name="myform" onsubmit="return check();">  
            <input type="radio" name="grp5" value="Chennai" >Chennai<br>  
             <input type="radio" name="grp5" value="Bangalore" >Bangalore<br>  
                 <input type="radio" name="grp5" value="Mumbai" >Mumbai<br>  
                     <input type="radio" name="grp5" value="Hyderabad" >Hyderabad<br>  
                     <br><br><input type="submit" value="Show Result"> 
                     <input type="hidden" name="hidden" value="grp5"/>


        </form> 
        <%
            String s4=request.getParameter("grp4");
         %>
      </body>  
</html>

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ResultPage.jsp

<html>  
    <head>  
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">  
        <title>Quiz Result</title>  
    </head>  
    <body>  
          <%  
     String answer="New Delhi";  
     String s1=request.getParameter("grp");  
     if(s1.equals(answer))  
         {  
        out.println("Correct Answer");  
         }  
     else  
         {out.println("Wrong Answer! The Correct Answer is :"+answer);  
     }  
    %> 
    <%  
     String answer2="Tamilnadu";  
     String s2=request.getParameter("grp2");  
     if(s2.equals(answer2))  
         {  
        out.println("Correct Answer");  
         }  
     else  
         {out.println("Wrong Answer! The Correct Answer is :"+answer2);  
     }  
    %> 
    <%  
     String answer3="Alaska";  
     String s3=request.getParameter("grp3");  
     if(s3.equals(answer3))  
         {  
        out.println("Correct Answer");  
         }  
     else  
         {out.println("Wrong Answer! The Correct Answer is :"+answer3);  
     }  
    %> 
    <%  
     String answer4="Rajasthan";  
     String s4=request.getParameter("grp4");  
     if(s4.equals(answer4))  
         {  
        out.println("Correct Answer");  
         }  
     else  
         {out.println("Wrong Answer! The Correct Answer is :"+answer4);  
     }  
    %> 
        <%  
         String answer5="Bangalore";  
         String s5=request.getParameter("grp5");  
         if(s5.equals(answer5))  
             {  
            out.println("Correct Answer");  
             }  
         else  
             {out.println("Wrong Answer! The Correct Answer is :"+answer5);  
         }  
        %> 


    </body> 
</html>

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非常感谢您的帮助.提前致谢

Answer 1

EJK*_*EJK 5

如果您想要可以跨多个页面访问的数据,请考虑使用会话来存储数据.例如,如果page1.jsp将一个表单参数"page1Result"提交到page2.jsp,那么在page2.jsp中,执行以下操作:

String page1Result = request.getParameter("page1Result");
request.getSession().setAttribute("page1Result", page1Result);

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然后在某个时间点(例如第5页),您可以访问page1值,如下所示:

String page1Value = (String)request.getSession().getAttribute("page1Result);

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================================================== ==============================所以将此应用于您的代码:

在page2 jsp中,将文件末尾的scriptlet更改为:

    <%
     String s1=request.getParameter("grp");
     request.getSession().setAttribute("s1", s1);
     %>

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在第3页的JSP中,将脚本更改为:

    <%
     String s2=request.getParameter("grp2");
     request.getSession().setAttribute("s2", s2);
     %>

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等等.

最后在ResultPage.jsp上(只显示答案2的示例一行)

out.println("Wrong Answer! The Correct Answer for question 2 is :"+session.getAttribute("s2"));

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