springMVC学习memo

下面代码的注释部分、若把APIBase类的访问限制改为private、或者protected、则在login requestmapping方法上throw出的ParameterErrorException不能被APIBase里的handleParameterErrorException方法捕获（将会被其父类Base的handleException方法捕获）。
故在使用JAVA的注解时一定要注意所注解的类是否为public的。

public class UserController {
	public static class Base {		
		
		@ExceptionHandler(Exception.class)
		public @ResponseBody
		Object handleException(HttpServletResponse response, Exception e) throws Exception {
			System.out.print("handle exception");
			return "ok";
		}
	}

	public static class ParameterErrorException extends Exception{}
	
        //APIBase类可见性改为private或protected都会有问题
        //private static class APIBase extends Base {	
        //protected static class APIBase extends Base {	
	public static class APIBase extends Base {		
		@ExceptionHandler(value={ParameterErrorException.class})
		public @ResponseBody
		Object handleParameterErrorException(ParameterErrorException e) throws Exception {	
			System.out.print("handle ParameterErrorException");
			return "ok";
		}
		
	}
	
	public static class Ajaxs{
		@Controller
		public static class Login extends APIBase {
						
			@RequestMapping(value = Urls.USER.AJAX_LOGIN, method = RequestMethod.POST)
			@ResponseBody
			public Object login(@ModelAttribute LoginVO loginVO, BindingResult br)
					throws Exception {
				if(br.hasErrors()){
					throw new Exception();
				}
				if(loginVO.getLoginName() == null){
					throw new ParameterErrorException();
				}
				return "OK";
			}
			
		}
		
		@Controller
		public static class Logout extends APIBase {
			@RequestMapping(value = Urls.USER.AJAX_LOGOUT, method = RequestMethod.GET)
			@ResponseBody
			public Object logout()
					throws Exception {
				return "OK";
			}
		}
	}

}