项目应用：自定义异常处理

@ControllerAdvice

spring官方文档上解释：

Indicates the annotated class assists a "Controller".

Serves as a specialization of @Component, allowing forimplementation classes to be autodetected through classpath scanning.

It is typically used to define @ExceptionHandler,@InitBinder, and@ModelAttributemethods that apply to all @RequestMapping methods.

One of annotations(), basePackageClasses(),basePackages() or its aliasvalue()may be specified to define specific subsets of Controllersto assist. When multiple selectors are applied, OR logic is applied -meaning selected Controllers should match at least one selector.

The default behavior (i.e. if used without any selector),the @ControllerAdvice annotated class willassist all known Controllers.

Note that those checks are done at runtime, so adding many attributes and usingmultiple strategies may have negative impacts (complexity, performance).

翻译：

指示带注释的类帮助一个“控制器”。

作为一个专业化的“组件，允许实现类是通过类路径自动扫描。

它通常用于定义@ ExceptionHandler，@和@ modelattributemethods initBinder，适用于所有“requestmapping方法。

一个annotations()，basepackageclasses()，basepackages()或其别名value()可能规定的特定子集，协助controllersto。当多个选择器的应用，或逻辑意义选择的控制器应与至少一个选择器应用。

默认的行为（即如果没有使用任何选择器），“controlleradvice注释将帮助所有已知的控制器类。

请注意，这些检查是在运行时完成的，所以加入了许多属性和多个策略可能有负面影响（复杂性、性能）。

对于作为异常处理的情况下，可以把它当做一个@contorller理解

@ControllerAdvicepublic class RestExceptionHandler extends ResponseEntityExceptionHandler  {    @Autowiredprivate  HttpServletRequest httpRequest;    @ExceptionHandler(value = { InnerHandleException.class })    public final String handleVMWareException(InnerHandleException ex, WebRequest request) {        return "/error";    }        @ExceptionHandler(value = { UserNotFoundException.class })    public final ModelAndView handlePowerException(UserNotFoundException ex, WebRequest request) {        //如果出现UserNotFoundException异常，则返回登录页，用于记录页面跳转情况下的登录过期处理        return new ModelAndView(new RedirectView("/login"));    }    @ExceptionHandler(value = { UserNotFoundAjaxException.class })    public final ResponseEntity<?> handleVMWareException(UserNotFoundAjaxException ex, WebRequest request) {       //如果出现UserNotFoundAjaxException 异常，则返回httpstatus=401，用于记录ajax请求情况下的登录过期处理       HttpHeaders headers = new HttpHeaders();        headers.setContentType(MediaType.parseMediaType("application/json;charset=UTF-8"));        return handleExceptionInternal(ex, ex.getMessage(), headers, HttpStatus.UNAUTHORIZED, request);    }   }

两个异常的定义

public class UserNotFoundException extends RuntimeException {    public UserNotFoundException(String message) {        super(message);    }    public UserNotFoundException() {    }}public class UserNotFoundAjaxException extends RuntimeException {    public UserNotFoundAjaxException(String message) {        super(message);    }    public UserNotFoundAjaxException() {    }} 

在service层抛出UserNotFoundException异常并在对应业务的controller层不做catch处理，即可进入@ControllerAdvice标记的异常处理方法。对于页面跳转直接做转到登录页处理，对于ajax请求则通过jquery做处理。

$.ajax({            type: "get",            url: "/courses/deljoin",            data:{                            data:data },            dataType:"json",            error: function(jqXHR, error, errorThrown) {                var status_code = jqXHR.status                if(status_code==401)//判断是否接收到401状态码                {                                  //返回登录处理                                   var curWwwPath = window.document.location.href;                      var pathName = window.document.location.pathname;                      var pos = curWwwPath.indexOf(pathName);                      var localhostPath = curWwwPath.substring(0, pos);              var url = localhostPath+"/login";            window.location.href=url;                }                },                success: function(data) {                               //成功刷新当前页面window.location.reload();              }