Question

我

在我的网络应用程序中，我正在使用动态下拉菜单进行选择 class，division和student_id。在选择班级时根据所选择的类别下拉填充.. Simmilarly in the student_id通过上课和分工来填写下拉列表。

我的问题是我无法同时将类值和除法值传递给jsp页面。

我的Home.jsp。代码是......

    <%@page import="java.sql.*"%>
 <html>
      <head>  
      <script language="javascript" type="text/javascript">  
      var xmlHttp  
      var xmlHttp


      function showdivision(str){
      if (typeof XMLHttpRequest != "undefined"){
      xmlHttp= new XMLHttpRequest();
      }
      else if (window.ActiveXObject){
      xmlHttp= new ActiveXObject("Microsoft.XMLHTTP");
      }
      if (xmlHttp==null){
      alert("Browser does not support XMLHTTP Request")
      return;
      } 
      var url="divisionn.jsp";
      url +="?passclassname=" +str;
      xmlHttp.onreadystatechange = divisionChange;
      xmlHttp.open("GET", url, true);
      xmlHttp.send(null);
      }




      function divisionChange(){   
      if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete"){   
      document.getElementById("division").innerHTML=xmlHttp.responseText   
      }   
      }



      function showstudid(str){

          var select = document.getElementById("class");
var classvalue = select.options[select.selectedIndex].value;

      if (typeof XMLHttpRequest != "undefined"){
        xmlHttp= new XMLHttpRequest();
        }
      else if (window.ActiveXObject){
        xmlHttp= new ActiveXObject("Microsoft.XMLHTTP");
        }
      if (xmlHttp==null){
      alert("Browser does not support XMLHTTP Request")
      return;
      } 
      var url="studid.jsp";
      url +="?passdivision=" +encodeURI(str);
      url +="&passclass=" +encodeURI(classvalue);

      xmlHttp.onreadystatechange = studidchange;
      xmlHttp.open("GET", url, true);
      xmlHttp.send(null);
      }


      function studidchange(){   
      if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete"){   
      document.getElementById("studid").innerHTML=xmlHttp.responseText   
      }   
      } 



      </script>  
      </head>  
      <body>  
      <table border="1">
      <tr><th>Class</th><th>Division</th><th>studid</th></tr>
      <tr><td>
      <select name='class' onchange="showdivision(this.value)">  
       <option value="none">Select</option>  
    <%
 Class.forName("com.mysql.jdbc.Driver");  
 Connection con = DriverManager.getConnection("jdbc:mysql://localhost/demo","root","password");  
 Statement stmt = con.createStatement();  
 ResultSet rs = stmt.executeQuery("Select class from class1");
 while(rs.next()){
     %>
      <option value="<%=rs.getString(1)%>"><%=rs.getString(1)%></option>  
      <%
 }
     %>
      </select> 
      </td>
      <td id='division'><select name='division' >  
      <option value='-1'></option>  
      </select>
      </td>
       <td id='studid'> <select name='studid' >  
      <option value='-1'></option>  
      </select>   
      </td>
      </tr>
      </table>
      </body> 
      </html>

Divisionn.jsp代码是..

<%@page import="java.sql.*"%>
<%
String classs=request.getParameter("passclassname");  
 String bu="<select name='division' onchange='showstudid(this.value);'><option value='-1'>Select</option>";  
 try{
 Class.forName("com.mysql.jdbc.Driver");  
 Connection con = DriverManager.getConnection("jdbc:mysql://localhost/demo","root","password");  
 Statement stmt = con.createStatement();  
 ResultSet rs = stmt.executeQuery("Select division_no from class1 where class='"+classs+"' ");  
   while(rs.next()){
   bu=bu+"<option value='"+rs.getString(1)+"'>"+rs.getString(1)+"</option>";  
   }  
 bu=bu+"</select>";  
 response.getWriter().println(bu); 
 }
 catch(Exception e){
     System.out.println(e);
 }

 %>

studid.jsp代码是......

   <%-- 
    Document   : divisionn
    Created on : Nov 26, 2016, 11:13:27 AM
    Author     : Jithin
--%>


<%@page import="java.sql.*"%>
<%
String division=request.getParameter("passdivision");  

String classs=request.getParameter("passclass");  



 String bu="<select name='division'><option value='-1'>---Select--</option>";  
 try{
 Class.forName("com.mysql.jdbc.Driver");  
 Connection con = DriverManager.getConnection("jdbc:mysql://localhost/demo","root","password");  
 Statement stmt = con.createStatement();  
 ResultSet rs = stmt.executeQuery("Select studid from class1 where division_no='"+ division+"' and class='"+ classs+"' ");  
   while(rs.next()){
   bu=bu+"<option value='"+rs.getString(1)+"'>"+rs.getString(1)+"</option>";  
   }  
 bu=bu+"</select>";  
 response.getWriter().println(bu); 
 }
 catch(Exception e){
     System.out.println(e);
 }

 %>

此代码无效..问题在于传递所选类名的代码..

function showstudid(str){

          var select = document.getElementById("class");
var classvalue = select.options[select.selectedIndex].value;

      if (typeof XMLHttpRequest != "undefined"){
        xmlHttp= new XMLHttpRequest();
        }
      else if (window.ActiveXObject){
        xmlHttp= new ActiveXObject("Microsoft.XMLHTTP");
        }
      if (xmlHttp==null){
      alert("Browser does not support XMLHTTP Request")
      return;
      } 
      var url="studid.jsp";
      url +="?passdivision=" +encodeURI(str);
      url +="&passclass=" +encodeURI(classvalue);

      xmlHttp.onreadystatechange = studidchange;
      xmlHttp.open("GET", url, true);
      xmlHttp.send(null);
      }

任何人都可以帮我找到解决方案..提前谢谢......

Answer 1

要通过URL传递多个参数，您需要使用正确的URL编码。

var url="studid.jsp";
url +="?passdivision=" +encodeURI(str);
url +="&passclass=" +encodeURI(xclass);

请注意，其他参数由＆amp;分隔。并且encodeURI函数将对您的数据进行URL编码。

另外考虑使用预准备语句，因为您的SQL查询有明显的SQL注入漏洞。

如何在ajax（JSP）中传递选定的下拉值？

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