相信大家對攔截器和切面的概念已經不陌生了，本文我們就看一些在應用市場中，攔截器和切面的使用是怎樣的。
攔截器的使用：每次接收到某個請求之前，都會調用此攔截器中的方法，其中preHandle方法如果return true,表示繼續(xù)調用對應的controller,如果return false，
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public class CheckLoginInterceptor implements HandlerInterceptor { private Logger logger = Logger.getLogger(CheckLoginInterceptor.class); private static String TOKEN_VALID_MSG ; static { TOKEN_VALID_MSG=JsonUtil.writeObject2JSON(new AMSResultVO(CodeNum.TOKEN_VALID, CodeMessage.TOKEN_VALID)); } public Boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { //request.getMethod獲取請求是get,post等 if ("OPTIONS".equals(request.getMethod())) { // 指定允許其他域名訪問 response.setHeader("Access-Control-Allow-Origin", "*"); // 響應類型 response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE"); // 響應頭設置 response.setHeader("Access-Control-Allow-Headers", "Content-Type, x-requested-with, X-Custom-Header"); response.setStatus(204); return true; } // 獲取從header中得到的數據 String userName = request.getHeader(CommonConsts.PARAM_USER_NAME); String userToken = request.getHeader(CommonConsts.PARAM_USER_TOKEN); Boolean result = true; String method = request.getRequestURI(); if(method.equals("/ams/fileUpload")) { return true; } if(StringUtil.isEmpty(userName) || StringUtil.isEmpty(userToken)) { result = false; } else { result = TokenUtil.validToken(userName, userToken); } // token校驗失敗 if(!result) { response.setContentType("text/html;charset=UTF-8"); response.getWriter().print(TOKEN_VALID_MSG); response.getWriter().flush(); response.getWriter().close(); } return result; } public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception { } public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception { }} |
切面的使用：
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//壞繞通知：需要攜帶ProceedingJoinPoint類型的參數//環(huán)繞通知類似于動態(tài)代理的全過程：ProceedingJoinPoint類型的參數可以決定是否執(zhí)行目標方法//且環(huán)繞通知必須有返回值，返回值即目標方法的返回值。@Around("execution(* com.sowell.controller.*Controller.*(..))") public Object aroundMethod(ProceedingJoinPoint pjd) { Object result = null; String methodName = pjd.getSignature().getName(); Object args = Arrays.asList(pjd.getArgs()); //執(zhí)行目標方法 try { logger.info("request channels begin, param{pageNum:" + methodName + ", pageSize:" + args); //前置通知，表示在此之前的代碼會在調用controller之前調用 result = pjd.proceed(); recordOprationLog(result, methodName, result); //后置通知 logger.info("Arround:The method "+ methodName+" ends"); } catch (Throwable e) { e.printStackTrace(); //異常通知 logger.error("Arround:The method "+ methodName+"occurs exception:"+e); //throw new RuntimeException(e); //不拋出異常的話，異常就被上面抓住，執(zhí)行下去，返回result，result值為null，轉換為int } //返回通知 logger.info("Arround:The method "+ methodName+" ends with the Result "+ result); return result;} |
總結
以上就是本文關于應用市場中Java攔截器和切面的使用實例詳解的全部內容，希望對大家有所幫助。感興趣的朋友可以繼續(xù)參閱本站其他相關專題，如有不足之處，歡迎留言指出。感謝朋友們對本站的支持！
原文鏈接：http://blog.csdn.net/qq_28893679/article/details/72841958
