一、ERROR Filter

错误过滤器用来处理zuul异常，一般使作为打印异常堆栈、跳转异常页面、转换异常信息格式返回等操作。

Zuul已定义的错误过滤器SendErrorFilter，如果RequestContext.getThrowable()不为null，则转发到/error（默认情况下）。您可以通过设置error.path属性来更改默认转发路径（/error）。

 

二、自定义错误过滤器

本文自定义错误过滤器用来将json格式请求的异常信息转换成json格式返回。

 

三、实现代码

@Component
@Slf4j
public class ErrorFilter extends ZuulFilter {//按类型对过滤器进行分类。Zuul中的标准类型是"pre"用于预路由筛选，"route"用于路由到原点，"post"用于后路由筛选，"error"用于错误处理。//我们还支持静态响应的"static"类型请参阅StaticResponseFilter。可以通过调用FilterProcessor.runFilters(type)//前置过滤器必须返回error@Overridepublic String filterType() {return FilterConstants.ERROR_TYPE;}//必须为过滤器定义filterOrder。如果优先级对筛选器不重要，则过滤器可能具有相同的过滤器顺序//过滤器顺序不需要是连续的@Overridepublic int filterOrder() {return FilterConstants.SEND_ERROR_FILTER_ORDER - 10;}//默认情况下，zuulfilter是静态的；它们不携带状态。这可以通过将isStaticFilter属性重写为false来重写@Overridepublic boolean isStaticFilter() {return super.isStaticFilter();}//要禁用此筛选器的Archaius属性的名称。默认情况下，它是zuul.[classname].[filtertype].disable@Overridepublic String disablePropertyName() {return super.disablePropertyName();}//如果为true，则过滤器已被archaius禁用，不会运行@Overridepublic boolean isFilterDisabled() {return super.isFilterDisabled();}//此方法返回的"true"表示应该调用run方法//如果应该调用run方法，则返回true。false不会调用run方法@Overridepublic boolean shouldFilter() {RequestContext ctx = RequestContext.getCurrentContext();String contentType = ctx.getRequest().getContentType();if (contentType == null) {return true;}MediaType mediaType = MediaType.valueOf(contentType);if(mediaType == null){return true;}return MediaType.APPLICATION_JSON.includes(mediaType);}//如果shouldFilter方法为true，则将调用此方法。这种方法是ZuulFilter的核心方法//返回一些可以返回的任意工件。当前的实现忽略了它。//如果在执行期间发生错误，则引发ZuulException@Overridepublic Object run() throws ZuulException {RequestContext context = RequestContext.getCurrentContext();ZuulException exception = findZuulException(context.getThrowable());context.remove("throwable");//去掉已处理的错误信息try {HttpServletResponse response = context.getResponse();response.setContentType("application/json; charset=utf8");response.setStatus(exception.nStatusCode);PrintWriter writer = null;try {writer = response.getWriter();Map<String, Object> map = new HashMap<>();map.put("code", exception.nStatusCode);map.put("msg", exception.errorCause);map.put("detail", exception.getMessage());String retStr = JSON.toJSONString(map);writer.print(retStr);writer.flush();} catch (IOException e) {e.printStackTrace();} finally {if (writer != null) {writer.close();}}}catch (Exception e){log.error("error filter exception", e);}return null;}protected ZuulException findZuulException(Throwable throwable) {if (throwable.getCause() instanceof ZuulRuntimeException) {Throwable cause = null;if (throwable.getCause().getCause() != null) {cause = throwable.getCause().getCause().getCause();}if (cause instanceof ClientException && cause.getCause() != null&& cause.getCause().getCause() instanceof SocketTimeoutException) {ZuulException zuulException = new ZuulException("", 504,ZuulException.class.getName() + ": Hystrix Readed time out");return zuulException;}// this was a failure initiated by one of the local filtersif (throwable.getCause().getCause() instanceof ZuulException) {return (ZuulException) throwable.getCause().getCause();}}if (throwable.getCause() instanceof ZuulException) {// wrapped zuul exceptionreturn (ZuulException) throwable.getCause();}if (throwable instanceof ZuulException) {// exception thrown by zuul lifecyclereturn (ZuulException) throwable;}// fallbackreturn new ZuulException(throwable, HttpStatus.INTERNAL_SERVER_ERROR.value(), null);}
}