Spring Interceptor拦截器流程

Spring拦截器流程

 

示例 - 登陆验证

• 编写Annotation, 用于标识不需要进行登陆验证的请求方法

  @Target(ElementType.METHOD)
  @Retention(RetentionPolicy.RUNTIME)
  public @interface LoginNotNeed {
  	
  }
  

• 编写Interceptor

  public class LoginInterceptor extends HandlerInterceptorAdapter {
  	
  	Logger logger = LoggerFactory.getLogger(LoginInterceptor.class);
  	
  	@SuppressWarnings("unchecked")
  	@Override
  	public boolean preHandle(HttpServletRequest request,
  			HttpServletResponse response, Object handler) throws Exception {
  		
  		HandlerMethod handlerMethod = (HandlerMethod) handler;
  		Method method = handlerMethod.getMethod();
  		
  		if (method.isAnnotationPresent(LoginNotNeed.class)) {
  			return super.preHandle(request, response, handler);
  		} else {
  			HttpSession session = request.getSession();
  			Map<String, Object> loginUser = (Map<String, Object>) session.getAttribute(LoginEnum.LOGIN_USER.toString());
  			if (null == loginUser) {
  				logger.debug("user isn't logged in.");
  				request.setAttribute("msg", "LoginInterceptor - 错误提示: 用户未登录");
  				logger.debug("request.getRequestURI() = {} ", request.getRequestURI());
  				session.setAttribute(LoginEnum.LAST_REQUEST_URL_NO_LOGIN.toString(), 
  						request.getRequestURI().replaceFirst(request.getContextPath(), ""));
  				request.getRequestDispatcher("/login").forward(request, response);				
  				return false;
  			} else {
  				return super.preHandle(request, response, handler);
  			}
  		}
  		
  	}
  
  }

• 配置interceptor

  <!-- 登陆拦截器 -->
  	<bean id="loginInterceptor"
  	    class="com.vserve.smartmedia.LoginInterceptor"></bean>
  
  <!-- 拦截器配置 -->
  	<mvc:interceptors>
  	    <mvc:interceptor>
  	        <mvc:mapping path="/**"/>
  	        <mvc:exclude-mapping path="/assets/**"/>
  	        <ref bean="loginInterceptor"/>
  	    </mvc:interceptor>
  	</mvc:interceptors>

• 使用示例

  	/**
  	 * 跳转到登陆页面
  	 * @return
  	 */
  	@LoginNotNeed
  	@RequestMapping("/login")
  	public String toLogin() {
  		return "/login";
  	}
  
  	/**
  	 * 主页面
  	 * @param req
  	 * @return
  	 */
  	@RequestMapping("/main")
  	public String toMain(HttpServletRequest req) {		
  		return "/main";
  	}