【JavaEE企业应用实战学习记录】authorityFilter

package sanglp.servlet;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.annotation.WebInitParam;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import java.io.IOException;



/**
 * Created by Administrator on 2016/10/5.
 */
@WebFilter(filterName = "authority",urlPatterns = {"/*"},initParams = {
    @WebInitParam(name = "encoding",value = "UTF-8"),
        @WebInitParam(name = "loginPage",value = "/chap2/login.jsp"),
        @WebInitParam(name = "proLogin", value="/chap2/proLogin.jsp")
})
public class AuthorityFilter implements Filter {
    //用于访问Filter的配置信息
    private FilterConfig config;

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        this.config=filterConfig;
    }

    @Override
    public void destroy() {
        this.config=null;
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        //获取该Filter的配置参数
        String encoding=config.getInitParameter("encoding");
        String loginPage=config.getInitParameter("loginPage");
        String proLogin=config.getInitParameter("proLogin");
        //设置request编码用的字符集
        servletRequest.setCharacterEncoding(encoding);
        HttpServletRequest hreq=(HttpServletRequest) servletRequest;
        HttpSession session=hreq.getSession(true);
        //获取客户请求的页面
        String requestPath=hreq.getServletPath();
        //如果session范围的user为null即表明没有邓丽。且用户请求的既不是登录页面，也不是处理登录的页面
        if(session.getAttribute("user")==null&&!requestPath.endsWith(loginPage)&&!requestPath.endsWith(proLogin)){
            servletRequest.setAttribute("tip","您还没有登录");
            servletRequest.getRequestDispatcher(loginPage).forward(servletRequest,servletResponse);

        }else{
            //履行请求
            filterChain.doFilter(servletRequest,servletResponse);
        }
    }
}