web 过滤器

两个过滤：第一个能过滤URL地址栏上下文后以mgr开头的页面，第二个能滤上下文后面的所有页面也就是根目录下的所有页面

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
		  http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
           version="3.0">
    <filter>
        <filter-name>LoginFilter</filter-name>
        <filter-class>com.filter.LoginFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>LoginFilter</filter-name>
        <url-pattern>/mgr/*</url-pattern>
<!--        只过滤/mgr/*的页面，URL以/mgr/开头的页面,一般login.jsp，regist.jsp，首页不需要过滤-->
    </filter-mapping>

    <filter>
        <filter-name>Fileter</filter-name>
        <filter-class>com.filter.Fileter</filter-class>
        <!--        增加程序的扩展性，只要改一处utf-8,类里全部就改了，省的多次修改-->
        <init-param>
            <param-name>charset</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>Fileter</filter-name>
        <url-pattern>/* </url-pattern>
<!--        *代表那个请求能进入过滤器-->
        <!--      /*  上下文后写任意路径都能够先通过过滤器，先走过滤器后走servlet-->
    </filter-mapping>
</web-app>

Fileter改编码格式 

 

package com.filter;

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

public class Fileter implements Filter  {

        private String charset;

        @Override
        public void init(FilterConfig filterConfig) throws ServletException {
            charset = filterConfig.getInitParameter("charset");
        }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest req=(HttpServletRequest)servletRequest;
        req.setCharacterEncoding(charset);
        filterChain.doFilter(req,servletResponse);//filterChain.doFilter让程序继续向下执行
    }

}

LoginFilter如果没有登陆就访问功能页面（如写文章）就会自动跳转到登录页面进行登录 

package com.filter;

import com.blog.util.Key;
import com.pojo.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 doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest req=(HttpServletRequest)servletRequest;
        HttpServletResponse resp=(HttpServletResponse)servletResponse;
        //从session中获取对象，如果有继续提交文章，如果没有就重新跳转到登录页面
        HttpSession session=req.getSession();
        User user=(User) session.getAttribute(Key.SISSION_USER);
        if(user!=null){
            filterChain.doFilter(req,resp);
        }else{
//            转发：服务器之间的操作浏览器不参与并且地址不变
//            重定向：浏览器之间的跳转，地址栏改变所以要重新获取上下文
            String context=req.getContextPath();
            resp.sendRedirect(context+"/login.jsp");
        }
    }
}
评论列表( 0 )