24.自定义规则异常返回

扩展：自定义异常返回

/**
 * 自定义异常返回页面
 */
@Component
public class ExceptionHandlerPage implements UrlBlockHandler {
    @Override
    public void blocked(HttpServletRequest request, HttpServletResponse response, BlockException e) throws IOException {
        //BlockException 异常接口，包含Sentinel的五个异常
        //FlowException 限流异常
        //DegradeException 降级异常
        //ParamFlowException 参数限流异常
        //AuthorityException 授权异常
        //SystemBlockException 系统负载异常

        response.setContentType("application/json;charset=UTF-8");
        ResponseData responseData = null;

        if (e instanceof FlowException) {
            responseData = new ResponseData(-1, "接口被限流了...");
        } else if (e instanceof DegradeException) {
            responseData = new ResponseData(-2, "接口被降级了...");
        } else if (e instanceof ParamFlowException) {
            responseData = new ResponseData(-3, "接口被参数限流了...");
        } else if (e instanceof AuthorityException) {
            responseData = new ResponseData(-4, "接口授权异常了...");
        } else if (e instanceof SystemBlockException) {
            responseData = new ResponseData(-5, "接口系统负载异常了...");
        }
        response.getWriter().write(JSON.toJSONString(responseData));
    }
}

@Data
@AllArgsConstructor //全参构造
@NoArgsConstructor
        //无参构造
class ResponseData {
    private int code;
    private String message;
}