Question

我正在使用Servlet，JSP模型在JSP复选框中显示多个值。复选框是动态创建的。（我有一个字符串，将其删除以获取用作复选框值的注释值。）复选框值显示在屏幕上。但是，我看不到捕获的选择（例如，有5个选项可供选择，我检查2个框。）

我也尝试过jsp文件。给我空指针错误。
＆LT;％

   System.out.println("Values selected:  ");
     String[] checkedIds = request.getParameterValues("checkedRows");

    System.out.println(" " + checkedIds[0] + " " + checkedIds[1]);

%>

QueryString1.java

package g6gQRY.QRYstring;

import g6gQRY.annotateQRY.*;

import java.io.IOException;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import java.util.*;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import javax.servlet.ServletRequest;    



public class QueryString1 extends HttpServlet {

protected void doGet(HttpServletRequest request, HttpServletResponse    response) throws ServletException, IOException {
    // TODO Auto-generated method stub
}


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

String querystring =request.getParameter("querystring");

System.out.println("Query String is: " + querystring);


ArrayList<String> A1 = new ArrayList<String>();



annotateQuery.queryToAnnotate(querystring, A1);



request.setAttribute("questring", A1);

String[] checkedIds = request.getParameterValues("checkedRows"); 

RequestDispatcher view = request.getRequestDispatcher("queryResult.jsp");

view.forward(request, response);              


       // println not working, shows null

      //         String arrayAsString = Arrays.toString(checkedIds);
      //         System.out.println("Values selected:  " + arrayAsString);


  }}
  }

queryResult.jsp是：

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>


<%@ page import="java.util.*" %>   
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>   


<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"     "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<h1> Query Results JSP </h1>
<br><br>
<p>

<table>


<c:forEach var="annotateVar" items="${questring}">
<tr><td>    <input type="checkbox" name="checkedRows" value="${annotateVar}">
<c:out value="${annotateVar}"  />  </td></tr>

</c:forEach>    


<tr><td align="center"><input type="submit" value="Submit"></td></tr>


</table>

</body>
</html>

web.xml文件是：

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
     http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    version="2.5">

<servlet>
<description></description>
<servlet-name>QueryString1</servlet-name>
<servlet-class>g6gQRY.QRYstring.QueryString1</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>QueryString1</servlet-name>
<url-pattern>/queryStr</url-pattern>
</servlet-mapping>
</web-app>

无法使用request.getParameterValues（＆＃34; checkedRows＆＃34;）

0 个答案: