自动登录过滤器实现-优快云博客

本文链接：https://blog.youkuaiyun.com/wxzyzydd/article/details/69487599

本文介绍了一种自动登录功能的实现方式，通过自定义Servlet过滤器检查用户的Cookie信息，并自动进行登录验证，若验证成功则将用户信息保存到Session中。

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package com.yigli.filter;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import com.yingli.dao.EmpDao;
import com.yingli.daoImpl.EmpDaoImpl;
import com.yingli.entity.Emp;


/**
 * Servlet Filter implementation class AutoLogin
 */
public class AutoLogin implements Filter {

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

	/**
	 * @see Filter#destroy()
	 */
	public void destroy() {
		// TODO Auto-generated method stub
	}

	/**
	 * @see Filter#doFilter(ServletRequest, ServletResponse, FilterChain)
	 */
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
		HttpServletRequest req=(HttpServletRequest)request;
		HttpServletResponse res=(HttpServletResponse) response;
		//1 取出cookie 
		HttpSession session = req.getSession();
		Emp emp=(Emp) session.getAttribute("user");
		if(emp==null){
			String path=req.getRequestURL().toString();
			if(!path.contains("/login")){
				Cookie [] cookies=req.getCookies();
				 Cookie cookie=null;
				 for(int i=0;cookies!=null&&i<cookies.length;i++){
		               if("empCookie".equals(cookies[i].getName())){
		            	    cookie=cookies[i];
		            	    break;
		               }			 
				 } 
				if(cookie!=null){
					// 2 验证数据库 
					 String [] vs=cookie.getValue().split("-");
					 EmpDao ed=new EmpDaoImpl();
					 emp=ed.login(vs[0], vs[1]);
					//   保存session  
					  if(emp!=null){
						  req.getSession().setAttribute("user",emp);
					  }
				}
			}
		}
		chain.doFilter(request, response);
	}

}

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