与同步调用类似，InvalidSymbolException 指示 请求已到达服务提供程序，该提供程序抛出业务异常，指示符号无效。
Similar to a synchronous invocation, InvalidSymbolException indicates that the request has reached the service provider, which has thrown a business exception stating that the symbol is invalid.
当它到达Web服务网关时，摘取出这个令牌符号，并且继续路由这个请求。
Extract the token and route the request when it arrives at the Web Services Gateway.
应用推荐