相信大家对拦截器和切面的概念已经不陌生了,本文我们就看一些在应用市场中,拦截器和切面的使用是怎样的。
拦截器的使用:每次接收到某个请求之前,都会调用此拦截器中的方法,其中preHandle方法如果return true,表示继续调用对应的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获取请求是get,post等 if ( "OPTIONS" .equals(request.getMethod())) { // 指定允许其他域名访问 response.setHeader( "Access-Control-Allow-Origin" , "*" ); // 响应类型 response.setHeader( "Access-Control-Allow-Methods" , "POST, GET, OPTIONS, DELETE" ); // 响应头设置 response.setHeader( "Access-Control-Allow-Headers" , "Content-Type, x-requested-with, X-Custom-Header" ); response.setStatus( 204 ); return true ; } // 获取从header中得到的数据 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校验失败 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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//坏绕通知:需要携带ProceedingJoinPoint类型的参数 //环绕通知类似于动态代理的全过程:ProceedingJoinPoint类型的参数可以决定是否执行目标方法 //且环绕通知必须有返回值,返回值即目标方法的返回值。 @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()); //执行目标方法 try { logger.info( "request channels begin, param{pageNum:" + methodName + ", pageSize:" + args); //前置通知,表示在此之前的代码会在调用controller之前调用 result = pjd.proceed(); recordOprationLog(result, methodName, result); //后置通知 logger.info( "Arround:The method " + methodName+ " ends" ); } catch (Throwable e) { e.printStackTrace(); //异常通知 logger.error( "Arround:The method " + methodName+ "occurs exception:" +e); //throw new RuntimeException(e); //不抛出异常的话,异常就被上面抓住,执行下去,返回result,result值为null,转换为int } //返回通知 logger.info( "Arround:The method " + methodName+ " ends with the Result " + result); return result; } |
总结
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原文链接:http://blog.csdn.net/qq_28893679/article/details/72841958