Java web项目中的强制登录

为了避免直接进入项目中存在的页面，使用filter过滤器

新建一个类loginFilter:

package com.tjcu.filter;

import com.tjcu.entity.User;

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
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;
        HttpSession session = request.getSession();
        User user = (User) session.getAttribute("user");
        HttpServletResponse response = (HttpServletResponse) servletResponse;
        if (user!=null) {
            filterChain.doFilter(request,response);
        }else {
            response.sendRedirect(request.getContextPath()+"/login.jsp");
        }
    }

    @Override
    public void destroy() {

    }
}

在web文件中通知服务器开发了这个过滤器

web.xml:

  
    loginFilter
    com.tjcu.filter.loginFilter
  
  
    loginFilter
    /main/*