首先在springmvc中配置攔截器

   <!-- 配置攔截器 -->
    <mvc:interceptors>
        <mvc:interceptor>
            <!-- 攔截所有mvc控制器 -->
            <mvc:mapping path="/**"/>
            <!-- mvc:exclude-mapping是另外一種攔截，它可以在你後來的測試中對某個頁面進行不攔截，這樣就不用在
                LoginInterceptor的preHandler方法裏面獲取不攔截的請求uri地址了(優選) 
 
-->
            <mvc:exclude-mapping path="/admin/loginPage.action" />
            <mvc:exclude-mapping path="/admin/varifyCode.action" />
            <bean class="nyist.admin.utils.LoginInterceptor"></bean>
        </mvc:interceptor>
    </mvc:interceptors>

然後寫攔截器：

public class LoginInterceptor implements HandlerInterceptor {

	@Override
	public void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, Exception arg3)
			throws Exception {
		// TODO Auto-generated method stub

	}

	@Override
	public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, ModelAndView arg3)
			throws Exception {
		// TODO Auto-generated method stub

	}

	@Override
	public boolean preHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2) throws Exception {
		HttpSession session = arg0.getSession();
		//String uri = request.getRequestURI(); // 獲取登錄的uri，這個是不進行攔截的
		//if(session.getAttribute("LOGIN_USER")!=null || uri.indexOf("system/login")!=-1) {// 說明登錄成功 或者 執行登錄功能			
		if(session.getAttribute("admin")!=null) {
			// 登錄成功不攔截
			return true;
		}else {
			// 攔截後進入登錄頁面
			arg1.sendRedirect(arg0.getContextPath()+"/admin/loginPage.action");
			return false;
		}
	}
}

　　攔截器這樣就設置好了

SSM登陸攔截器實現