老师，不能跳转页面

点击OK，依旧会弹出这个对话框。

package com.imooc.icake.controller;

import com.imooc.icake.biz.AccountBiz;
import com.imooc.icake.biz.impl.AccountBizImplement;
import com.imooc.icake.entity.Account;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class DefaultController {
//调用业务层
    AccountBiz accountBiz = new AccountBizImplement();
//    /tologin.do
    public void toLogin(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
      request.getRequestDispatcher("/WEB-INF/pages/admin/login.jsp").forward(request,response);
    }

//    /login.do
    public void login(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String name = request.getParameter("account");
String password =request.getParameter("password");
Account account=accountBiz.login(name,password);
//        如果登录失败了
        if (account == null) {
            response.sendRedirect("toLogin.do");
        } else {
            request.getSession().setAttribute("ACCOUNT", account);
            response.sendRedirect("/admin/cake/list.do");
        }

    }
//    /quit.do
public void quit(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        request.getSession().setAttribute("ACCOUNT", null);
        response.sendRedirect("toLogin.do");
    }

}

package com.imooc.icake.global;

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class LoginFilter implements Filter {
@Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

@Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
HttpServletRequest request = (HttpServletRequest) servletRequest;
HttpServletResponse response = (HttpServletResponse) servletResponse;
Object object = request.getSession().getAttribute("ACCOUNT");
if (object == null) {
response.sendRedirect("toLogin.do");
        }
        filterChain.doFilter(request,response);
    }

@Override
    public void destroy() {

    }
}

还有就是为什么toLogin方法没有传参数使用转发。

复java_n 2021-04-02

源自：项目：商品信息管理 3-8 登陆

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1回答

好帮手慕小尤回答被采纳获得+3积分 2021-04-02 17:07:11

同学你好，1、根据提示，URL不能打开。请检查这个URL是否正确，如下图所示：所以建议同学查看路径是否正确。

2、没有参数也是可以使用请求转发的，如果只是页面跳转，使用转发和重定向都可以。具体使用场景如下：

1）如果是访问本项目外的页面，必须使用重定向。

2）如果在跳转时，想要携带request作用域中的数据一起跳转，必须使用转发。另外如果访问的页面在WEB-INF目录下，也必须有转发。如下所示：

注：因为WEB-INF是安全目录，不可以直接访问，直接访问会出现404异常

祝学习愉快！

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复java_n 提问者 #1

我测试出来就是这个路径，我是在设置了登录页面的登录过滤器后无法进入的
java.lang.NoSuchMethodException: com.imooc.icake.controller.CatalogController.toLogin(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
at java.lang.Class.getMethod(Class.java:1786)
at com.imooc.icake.global.GlobalController.service(GlobalController.java:56)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at com.imooc.icake.global.LoginFilter.doFilter(LoginFilter.java:22)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at com.imooc.icake.global.EncodingFilter.doFilter(EncodingFilter.java:24)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:543)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:690)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:615)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:818)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1626)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
java.lang.NoSuchMethodException
这是报的错

2021-04-02 17:26:07
复java_n 提问者 #2

如果代码正确就会自动跳转到/admin/toLogin.do上的对吧？

2021-04-02 17:33:08
好帮手慕小尤回复提问者复java_n #3

同学你好，1、java.lang.NoSuchMethodException意思是没有找到该方法。建议同学根据提示查看方法是否存在。或查看访问的路径对不对。
2、同学可以查看GlobalController类的56行，查看是否存在问题。

注：可以与源码进行对比。
3、是的，代码正确时并在未登陆的情况下会自动跳转到/admin/toLogin.do
注：同学不要在idea中进行访问，同学可以直接在浏览器中访问试一下。
祝学习愉快！

2021-04-02 18:59:25