springMVC拦截器配置

在spring 3.0甚础上，起来越多的用到了注解，从前的拦截器在配置文件中需要这样配置

<beans...>
    ...
    <bean id="measurementInterceptor"
        class="com.apress.springrecipes.court.web.MeasurementInterceptor"/>
    <bean class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
        <property name="interceptors">
            <list>
                <ref bean="measurementInterceptor"/>
            </list>
        </property>
        ...
    </bean>
    <bean class="org.springframework.web.servlet.mvc.support
        .ControllerClassNameHandlerMapping">
        <property name="interceptors">
            <list>
                <ref bean="measurementInterceptor"/>
            </list>
        </property>
    </bean>
    ....
</beans>

现在用注解只需要这样：

<mvc:interceptors>
        <mvc:interceptor>
            <mvc:mapping path="/*/*.shtml"/>//映射路径后缀名
            <bean class="x.x.x.filter.SessionFilter"/>//自定义拦截器
        </mvc:interceptor>
    </mvc:interceptors>

SessionFilter.java代码：

public class SessionFilter implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object o) throws Exception {
      //  后台session控制
        Object user=request.getSession().getAttribute("username");
        String returnUrl = request.getRequestURI();
        if(null==user){
            if(returnUrl.equals("/public/getImg.shtml")||returnUrl.equals("/public/checkLogin.shtml")||returnUrl.equals("/public/login.shtml")||returnUrl.equals("/public/logOut.shtml")){
                return true;
            }else{
                response.setContentType("text/html");
                response.setCharacterEncoding("utf-8");
                PrintWriter out = response.getWriter();
                StringBuilder builder = new StringBuilder();
                builder.append("<script type=\"text/javascript\" charset=\"UTF-8\">");
                builder.append("alert(\"请重新登陆！\");");
                builder.append("window.location.href=\"/public/login.shtml\";");
                builder.append("</script>");
                out.print(builder.toString());
                out.close();
                return false;
            }
        }
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse response, Object o, ModelAndView modelAndView) throws Exception {

    }

    @Override
    public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse response, Object o, Exception e) throws Exception {

    }


    /**
     * @param request
     * @return Create Date:2013-6-5
     * @author Shine
     * Description:获取IP
     */
    private String getIpAddr(HttpServletRequest request) {
        String ip = request.getHeader("x-forwarded-for");
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("Proxy-Client-IP");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("WL-Proxy-Client-IP");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getRemoteAddr();
        }
        return ip;
    }
}

这个拦截器的目的就是：用户所属的session不存在后进行对控制器请求的拦截，使跳转到首页。对于HandlerInterceptor这个类这里不多说，网上有的可能说的更好，这里只简单说下它的三个方法，preHandle、postHandle和afterCompletion。