Filter

1.字符集

@WebFilter(filterName="EcodingFilter",urlPatterns="/*")

public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {
        // TODO Auto-generated method stub
        request.setCharacterEncoding("utf-8");
        response.setCharacterEncoding("utf-8");
        chain.doFilter(request,response);
    }

2.限制没有登录的用户

设置一个path文件夹，里面的页面只要登录之后才可以查看

建立一个LoginFilter用来查看session中有没有用户登录的信息，如果没有就拦截，如果有就允许登录

 

@WebFilter(filterName="LoginFilter",urlPatterns="/path/*")

public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {
        // TODO Auto-generated method stub
        HttpServletRequest r = (HttpServletRequest)request;
        HttpServletResponse res = (HttpServletResponse)response;
        HttpSession  session = r.getSession();
        String user = (String)session.getAttribute("username");
        if(user != null){
            chain.doFilter(request, response);
        }else {
            String msg = "没有登录";
            r.setAttribute("error", msg);
            r.getRequestDispatcher("/PleaseLogin.jsp").forward(r, res);
        }
    }

 PleaseLogin.jsp

用来显示错误的error

<body>
    ${error }
</body>

 

posted @ 2016-08-17 16:38  式微胡不归  阅读(118)  评论(0)  编辑  收藏  举报