应用市场中Java拦截器和切面的使用实例详解

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 {	}}

//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;}