集中異常處理

以下代碼可在github獲取：https://github.com/Syske/learning-dome-code/tree/master/springboot-learning

方式一：ExceptionHandle

定義自己的異常類(lèi)型，根據(jù)不同類(lèi)型做不同處理，比如我定義的MyException：

public class MyException extends RuntimeException { public MyException(String msg) { super(msg); }}

然后通過(guò)MyExceptionHandle處理該異常，需要注意的是異常不能在filter中拋出，拋出也沒(méi)法捕獲

@RestControllerAdvicepublic class MyExceptionHandle { @ExceptionHandler(MyException.class) public Result exceptionHandle(MyException e) { return Result.getFailed( 'system error:MyException' + e.getMessage()); }}

在controller、service以及攔截器的預(yù)處理方法中都可以完美捕獲，這里特殊說(shuō)下攔截器：

public class MyInterceptor implements HandlerInterceptor { @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) { //throw new MyException('攔截器錯(cuò)誤：MyInterceptor'); // 這里的異常會(huì)完美捕獲，并返回 return true; } @Override public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) { throw new MyException('攔截器錯(cuò)誤：MyInterceptor'); /** 能捕獲異常信息并返回給客戶端，但并不會(huì)覆蓋已經(jīng)請(qǐng)求成功的返回結(jié)果，但會(huì)包含在返回結(jié)果中，比如我的返回結(jié)果： {'code':1,'success':true,'msg':'請(qǐng)求成功','result':true}{'code':0,'success':false,'msg':'system error:MyException攔截器錯(cuò)誤：MyInterceptor','result':null} */ } @Override public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) { throw new MyException('攔截器錯(cuò)誤：MyInterceptor'); // 這里拋出的異常并不能被捕獲，會(huì)直接在后臺(tái)拋出，相當(dāng)于回掉函數(shù)，請(qǐng)求結(jié)果已經(jīng)返回 }}

上面的解釋已經(jīng)夠清楚了，就不做過(guò)多說(shuō)明了。剛剛我們說(shuō)了，上面的這種方式，對(duì)于filter是不起作用的，下面我們說(shuō)的這種方式，主要就是針對(duì)filter來(lái)說(shuō)的

方式二：ExceptionFilter

定義一個(gè)controller，請(qǐng)求路徑可以自己指定，比如/error/exthrow:

@Controllerpublic class ExceptionController { @RequestMapping('/error/exthrow') public void rethrow(HttpServletRequest request) throws Exception { throw ((Exception) request.getAttribute('filter.error')); }}

再定義一個(gè)異常攔截器，在需要拋出異常的攔截器中直接拋出異常，然后在異常攔截器中try-catch，發(fā)生異常時(shí)直接轉(zhuǎn)發(fā)至前面定義的異常controller，這里需要注意的是，如果你的filter是實(shí)現(xiàn)Filter或者繼承OncePerRequestFilter，那你不需要任何處理，直接request.setAttribute('filter.error', e)就可以了。

由于我把自己的filter交給shiro管理，而且是繼承BasicHttpAuthenticationFilter的，不知到什么原因，直接catch到的異常類(lèi)型是ServletException，為了拿到真正的異常信息，我需要通過(guò)getCause()方法獲取filter中拋出的異常。因?yàn)閏ontroller拋出的異常最后還是會(huì)交給我們定義的MyExceptionHandle去處理，如果獲取到的異常不是我們自定義的異常或者他的子類(lèi)的話，就會(huì)返回500錯(cuò)誤（在這個(gè)示例前，我以為所有的filter都是這樣的，后來(lái)實(shí)踐后發(fā)現(xiàn)并不是這樣😂）。

@Componentpublic class ExceptionFilter implements Filter { @Override public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { try { chain.doFilter(request, response); } catch (Exception e) { request.setAttribute('filter.error', e); //將異常分發(fā)到/error/exthrow控制器 request.getRequestDispatcher('/error/exthrow').forward(request, response); } } @Override public void init(FilterConfig filterConfig) throws ServletException { } @Override public void destroy() { }}

我的filter:

實(shí)現(xiàn)Filter接口：

public class MyFilter implements Filter { @Override public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException { throw new MyException('MyFilter過(guò)濾器拋出異常'); //filterChain.doFilter(servletRequest, servletResponse); } }

filter2繼承OncePerRequestFilter：

public class MyFilter2 extends OncePerRequestFilter { @Override protected void doFilterInternal(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, FilterChain filterChain) throws ServletException, IOException { throw new MyException('MyFilter2異常'); }}

filter配置類(lèi)：

@Bean public FilterRegistrationBean myFilterRegistration() { FilterRegistrationBean registration = new FilterRegistrationBean(); registration.setFilter(new MyFilter()); registration.setName('myFilter'); registration.addUrlPatterns('/*'); //此處盡量小，要比其他Filter靠前 registration.setOrder(1); return registration; } @Bean public FilterRegistrationBean myFilter2Registration() { FilterRegistrationBean registration = new FilterRegistrationBean(); registration.setFilter(new MyFilter2()); registration.setName('myFilter2'); registration.addUrlPatterns('/*'); //此處盡量小，要比其他Filter靠前 registration.setOrder(2); return registration; } /** * 配置攔截器 * @return */ @Bean public FilterRegistrationBean exceptionFilterRegistration() { FilterRegistrationBean registration = new FilterRegistrationBean(); registration.setFilter(new ExceptionFilter()); registration.setName('exceptionFilter'); //此處盡量小，要比其他Filter靠前 registration.setOrder(-1); return registration; }

方式三：BasicErrorController

其實(shí)spring boot原生提供了異常集中處理，我們經(jīng)常會(huì)看到：

但是這種方式不夠友好，而且大部分情況不滿足我們的需求，我們可以通過(guò)繼承這個(gè)controller，然后重寫(xiě)error方法或者errorHtml方法，或者兩個(gè)都重寫(xiě)，區(qū)別是errorHtml是處理請(qǐng)求頭為text/html的請(qǐng)求發(fā)生的異常，而error是除了這個(gè)之外的其他異常。

下面是我定義的baseController，error部分返回的結(jié)果是空，還需要進(jìn)一步的研究：

@RestController@RequestMapping(value = 'error')public class MyBaseErrorController extends BasicErrorController { public MyBaseErrorController(ErrorAttributes errorAttributes) { super(errorAttributes, new ErrorProperties()); } @Override @RequestMapping(produces = {MediaType.ALL_VALUE}) public ResponseEntity<Map<String, Object>> error(HttpServletRequest request) { return new ResponseEntity<Map<String, Object>>(Result.failedResultMap(000, '未知錯(cuò)誤'), HttpStatus.OK); } @RequestMapping( produces = {'text/html'} ) public ModelAndView errorHtml(HttpServletRequest request, HttpServletResponse response) { HttpStatus status = this.getStatus(request); response.setStatus(status.value()); return null; } }

最后，對(duì)于以上問(wèn)題我最后的解決方法是繼承ErrorController，然后定義errorHtml和error，更重要的是@RequestMapping注解，然后在方法中response寫(xiě)入返回值，這種方式不夠優(yōu)雅：

@RestController@RequestMapping(value = 'error')public class MyBaseErrorController implements ErrorController { private static final String path_default = '/error'; @Autowired private ErrorAttributes errorAttributes; @RequestMapping(produces = {MediaType.ALL_VALUE}) public void error(HttpServletRequest request, HttpServletResponse response) { setJsonError(response); } @RequestMapping( produces = {'text/html'} ) public void errorHtml(HttpServletRequest request, HttpServletResponse response) { setJsonError(response); } @Override public String getErrorPath() { return path_default; } private void setJsonError(HttpServletResponse response) { PrintWriter writer = null; try { response.setStatus(200); response.setHeader('Content-type', 'text/html;charset=UTF-8'); response.setCharacterEncoding('UTF-8'); writer = response.getWriter(); writer.write(JSON.toJSONString(Result.getFailed('未知錯(cuò)誤', null))); } catch (IOException e) { e.printStackTrace(); } finally { if (writer != null) {writer.close(); } } }}

以上就是本文的全部?jī)?nèi)容，希望對(duì)大家的學(xué)習(xí)有所幫助，也希望大家多多支持好吧啦網(wǎng)。