springmvc里使用注解进行拦截器配置

springmvc本身不能像struts2那样使用注解拦截action,这在使用中非常不方便,我们来扩展下springmvc,增加一个类,就可以实现注解拦截器.

首先把下面这个类拷贝进去:

package interceptor;import java.lang.annotation.ElementType;import java.lang.annotation.Retention;import java.lang.annotation.RetentionPolicy;import java.lang.annotation.Target;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.springframework.web.method.HandlerMethod;import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;public abstract class BaseInterceptor extends HandlerInterceptorAdapter {    public String success;    public String failed;    public boolean isMyHandler(Object handler) {        if (!(handler instanceof HandlerMethod))            return false;        HandlerMethod handlerMethod = (HandlerMethod) handler;        Interceptor interceptor = handlerMethod.getMethodAnnotation(Interceptor.class);        if (interceptor == null)            return false;        if (!interceptor.name().equals(this.getClass().getSimpleName()) && !interceptor.name().equals(this.getClass().getName()))            return false;        success = interceptor.success();        failed = interceptor.failed();        return true;    }    @Override    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {        if (isMyHandler(handler)) {            return runHandler(response, runHandler(request, response));        }        return super.preHandle(request, response, handler);    }    public abstract boolean runHandler(HttpServletRequest request, HttpServletResponse response);    /**     * 运行结果     *      * @param response     * @param isInterceptor     *            是否拦截,true拦截,跳转向failed指向页面,false:不拦截,跳转向success指向页面;     *            success和failed为空时不做任何操作     * @return     * @throws Exception     */    public boolean runHandler(HttpServletResponse response, boolean isInterceptor) throws Exception {        if (!isInterceptor) {            if (!success.equals("")) {                response.sendRedirect(success);                return false;            }        } else {            if (!failed.equals("")) {                response.sendRedirect(failed);                return false;            }        }        return true;    }    @Target(ElementType.METHOD)    @Retention(RetentionPolicy.RUNTIME)    public static @interface Interceptor {        public String name();        public String success() default "";        public String failed() default "";    }}

以上代码仅支持spring3.1.6以上版本,低一些的版本赶快升级吧.说真的,如果不能注解拦截器,开发时候像是登录验证/权限认证太费事了.

---

自己写一个拦截器,继承与上面的类,如下:

package interceptor;import javax.annotation.Resource;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import service.UserServiceImpl;public class LoginCheck extends BaseInterceptor {    @Resource    private UserServiceImpl userService;    @Override    public boolean runHandler(HttpServletRequest request, HttpServletResponse response) {        //.....判断是否登陆,判断是否有权限等逻辑代码        return false;    }}

---

在springmvc配置文件中配置拦截器:

<mvc:interceptors>        <mvc:interceptor>            <mvc:mapping path="/**" />            <bean class="interceptor.LoginCheck"></bean>        </mvc:interceptor>    </mvc:interceptors>

拦截器配置为拦截所有controller.

---

在controller方法上写

@Interceptor(name = "LoginCheck", failed = "/user/login")

如:

@Interceptor(name = "LoginCheck", failed = "/user/login")    @RequestMapping("/user/del/{id}")    public void del(@PathVariable int id, HttpServletResponse response) throws IOException {        userService.del(id);        response.sendRedirect("/users/1");    }

这样在访问del方法的时候,就会先运行logincheck拦截器,如果拦截器拦截了,就会跳转到user/login页面,是不是和struts2的拦截器一样好用了?