Java 我无法在Servlet中获取cookie

我目前正在使用最新版本的eclipse和tomcat服务器（v8.5）

在我的代码的“Cookie Cookie[]=req.getCookies（）；”行的SqServlets.java文件中生成类型不匹配错误。 若它被解决了，那个么我将添加for循环并获得我的“k”值cookie，但该行中的第一个错误将被清除

Addservlets.java

package servlets;

import java.io.IOException;

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

public class Addservlet extends HttpServlet {

    public void doGet(HttpServletRequest req,HttpServletResponse res) throws ServletException, IOException {

        int i= Integer.parseInt(req.getParameter("num1"));
        int j= Integer.parseInt(req.getParameter("num2"));

        int k=i+j;

        String str=Integer.toString(k);

        Cookie cookie=new Cookie("k",str);
        res.addCookie(cookie);

        res.sendRedirect("sq");


    }

}

package servlets;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.tomcat.util.http.parser.Cookie;

public class SqServlets extends HttpServlet {

    public void doGet(HttpServletRequest req,HttpServletResponse res) throws IOException {

        int k=0;
        Cookie cookie[]= req.getCookies();

        k=k*k;

        PrintWriter out=res.getWriter();
        out.print("square value is = "+k);

    }


}

SqServlets.java

package servlets;

import java.io.IOException;

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

public class Addservlet extends HttpServlet {

    public void doGet(HttpServletRequest req,HttpServletResponse res) throws ServletException, IOException {

        int i= Integer.parseInt(req.getParameter("num1"));
        int j= Integer.parseInt(req.getParameter("num2"));

        int k=i+j;

        String str=Integer.toString(k);

        Cookie cookie=new Cookie("k",str);
        res.addCookie(cookie);

        res.sendRedirect("sq");


    }

}

package servlets;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.tomcat.util.http.parser.Cookie;

public class SqServlets extends HttpServlet {

    public void doGet(HttpServletRequest req,HttpServletResponse res) throws IOException {

        int k=0;
        Cookie cookie[]= req.getCookies();

        k=k*k;

        PrintWriter out=res.getWriter();
        out.print("square value is = "+k);

    }


}

---

我认为错误在于导入：

import org.apache.tomcat.util.http.parser.Cookie;

从HttpServletRequest的文档中，我们发现方法

getCookies

返回的

javax.servlet.http.Cookie

与您的声明不兼容

因此，请使用以下方法修复导入：

import javax.servlet.http.Cookie

然后使用相关API查找并获取cookie的值。
请将错误添加到PostDos
i
和
j
中是否有一些值在您的
Addservlet
类中，请尝试检查。对于（cookie c:cookie）{if（c.getName（）.equals（“k”）{k=Integer.parseInt（c.getValue（）；}我已使用上述代码获取cookie，但它给了我一个错误。类型异常报告消息null说明服务器遇到意外情况，使其无法满足请求。异常java.lang.NumberFormatException:null java.lang.Integer.parseInt（未知源）java.lang.Integer.parseInt（未知源）servlet.Addservlet.doGet（Addservlet.java:15）javax.servlet.http.HttpServlet.service（HttpServlet.java:634）javax.servlet.http.HttpServlet.service（HttpServlet.java:741）org.apache.tomcat.websocket.server.WsFilter.doFilter（WsFilter.java:52）