Spring-mvc登录方法及JSP的拦截

添加登录拦截器：LoginInterceptor

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

public class LoginInterceptor implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        Object user = request.getSession().getAttribute("LOGIN_USER");
        if (user == null) {
            response.sendRedirect("/login.jsp");
            System.out.println("尚未登录，跳到登录页面");
            return false;
        }

        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
            ModelAndView modelAndView) throws Exception {
        System.out.println("postHandle");
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
            throws Exception {
        System.out.println("afterCompletion");
    }

}

spring-mvc.xml 配置文件：

　　<mvc:interceptors>
        <mvc:interceptor>
            <!-- 拦截所有请求 -->
            <mvc:mapping path="/**"/> 
　　 　　　　 <!-- 排除拦截的请求 -->
　　　　　　　<mvc:exclude-mapping path="/user/login.do"/> 
　　　　　　　<bean class="com.dowave.interceptor.LoginInterceptor"></bean> 
　　　　</mvc:interceptor> 
　　</mvc:interceptors>

当 mvc:exclude-mapping 报错时，将 http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd 改成 3.2。

到此，就完成拦截器了。如果JSP代码没放在 WEB-INF 目录下还需要增加对 jsp 文件的拦截，如下：

增加登录过滤器 LoginFilter：

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.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class LoginFilter implements Filter {
    public void destroy() {

    }

    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain)
            throws ServletException, IOException {

        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;
        String currentURL = request.getRequestURI();
        String ctxPath = request.getContextPath();

        // 除掉项目名称时访问页面当前路径
        String targetURL = currentURL.substring(ctxPath.length());
        HttpSession session = request.getSession(false);

        // 对当前页面进行判断，如果当前页面不为登录页面
        if (!("/login.jsp".equals(targetURL))) {// 在不为登陆页面时，再进行判断，如果不是登陆页面也没有session则跳转到登录页面，
            if (session == null || session.getAttribute("LOGIN_USER") == null) {
                response.sendRedirect("/login.jsp");
                return;
            } else {
                // 这里表示正确，会去寻找下一个链，如果不存在，则进行正常的页面跳转
                filterChain.doFilter(request, response);
                return;
            }
        } else {
            // 这里表示如果当前页面是登陆页面，跳转到登陆页面
            filterChain.doFilter(request, response);
            return;
        }

    }

    public void init(FilterConfig filterConfig) throws ServletException {

    }

}

在 web.xml 增加：

　　 <!-- jsp拦截 -->
    <filter>
        <filter-name>LoginFilter</filter-name>
        <filter-class>com.dowave.interceptor.LoginFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>LoginFilter</filter-name>
        <!-- 这里表示对所有的以jsp后缀的文件有效，其它的无效 -->
        <url-pattern>*.jsp</url-pattern>
    </filter-mapping>

O了，本文到此结束，喜欢收藏哦