Question

我在尝试运行代码时收到错误。无法找到问题所在。我可能会遗漏一些细节，如果你能纠正它会很棒。

CalculateServlet

    import java.io.IOException;
    import javax.servlet.*;
    @WebServlet(name="CalculateServlet", urlPatterns={"/CalculateServlet"})
    public class CalculateServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

/**
 * Default constructor. 
 */
public CalculateServlet() {
    // TODO Auto-generated constructor stub
}

/**
 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
 */
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    //assuming request as the object of the HttpServletRequest Class.
    //retrieving & storing the values from the textboxes into the String Variables.
    String n1 = request.getParameter("fnum");
    int num1 = Integer.parseInt(n1); //Converting String into Integer Variable
    String n2 = request.getParameter("snum");
    int num2 = Integer.parseInt(n2); int ans=0;

    //performing calculation according to the selection made from the Radio Buttons named "calc".
    if(request.getParameter("calc").equals("Add"))
    ans = num1+num2;
    if(request.getParameter("calc").equals("Sub"))
    ans = num1-num2;
    if(request.getParameter("calc").equals("Div"))
    ans = num1/num2;
    if(request.getParameter("calc").equals("Multi"))
    ans = num1*num2;

    //assuming response as the object of the HttpServletResponse Class.
    //displaying output to the user 
    response.getWriter().println(ans); 

    response.getWriter().append("Served at: ").append(request.getContextPath());
}

/**
 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
 */
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    // TODO Auto-generated method stub
    doGet(request, response);
}}

的index.jsp

    <%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
    <body>
        <form action="CalculateServlet">
   <input type="text" name="fnum"/>
   <br/>
   <input type="text" name="snum"/>
   <br/>
   Select Operation
   <br/>
   <input type="radio" name="calc" value="Add"/>Add
   <input type="radio" name="calc" value="Sub"/>Subtract
   <input type="radio" name="calc" value="Div"/>Divide
   <input type="radio" name="calc" value="Multi"/>Multiply
   <br/>
   <input type="submit" value="Calculate" name="submit"/>
</form>
    </body>
</html>

Output1

Directory Structure

Answer 1

web.xml中的网址格式

<servlet-mapping>
    <servlet-name>CalculateServlet</servlet-name>
    <url-pattern>/CalculateServlet</url-pattern>
</servlet-mapping>

但是你的jsp将其提交给＆＃34;计算＆＃34;

<form action="calculate">

将其更改为，

<form action="CalculateServlet">

Answer 2

看起来你很亲密。

看一下这个帖子：

<form action="/sampleServlet" giving me exception

我认为您的问题是表单操作设置为计算

description请求的资源不可用

2 个答案: