Java if 条件检查空值和 null 值

Question

如何在 java 中为 Web 服务请求编写条件，在我的 Web 服务请求中，我传递一个包含 SpeedInfo 的元素。在 SpeedInfo 元素中，有两个子元素 Bandwidth 和 AccessSpeed。

这是我在 SoapUI 中的请求:

 <sch:SpeedInfo>
    <ns:Bandwidth xmlns:ns="http://lpp.att.com/logical/classofservice/schema/v1">4000000</ns:Bandwidth>
    <ns:AccessSpeed xmlns:ns="http://lpp.att.com/logical/classofservice/schema/v1">4000000</ns:AccessSpeed>
 </sch:SpeedInfo>

我的Java情况:

if (request.getSpeedInfo() == null || (request.getSpeedInfo() == null && request.getSpeedInfo().getBandwidth() == null)){
    throw new Exception(" SpeedInfo Bandwidth must be passed in the request ");
}

我需要我的条件来检查 3 种情况:

 1. if <speedInfo> itself is not present

 2. <sch:SpeedInfo> is present, but bandwidth not present:

  <sch:SpeedInfo>
      <ns:AccessSpeed xmlns:ns="http://lpp.att.com/logical/classofservice/schema/v1">40000000</ns:AccessSpeed>
  </sch:SpeedInfo>

 3. Bandwidth is present but no value  
   <sch:SpeedInfo>
      <ns:Bandwidth xmlns:ns="http://lpp.att.com/logical/classofservice/schema/v1"></ns:Bandwidth>
      <ns:AccessSpeed xmlns:ns="http://lpp.att.com/logical/classofservice/schema/v1">40000000</ns:AccessSpeed>
   </sch:SpeedInfo>

我收到的错误:

2016-02-02 09:45:48,349  WARN http-bio-8080-exec-3--[c0a8381152a2a943f51] c0a8381152a2a943f51 fw.ws.MessageInInterceptor:49 - Content input stream is NOT null, nothing to log in handleFault()?
2016-02-02 09:45:48,351  WARN http-bio-8080-exec-3--[c0a8381152a2a943f51] c0a8381152a2a943f51 cxf.phase.PhaseInterceptorChain:452 - Interceptor for {http://lpp.att.com/logical/v1}LogicalService#{http://lpp.att.com/logical/v1}classOfServiceAllocation has thrown exception, unwinding now
org.apache.cxf.interceptor.Fault: Unmarshalling Error: cvc-datatype-valid.1.2.1: '' is not a valid value for 'integer'. 
at    org.apache.cxf.jaxb.JAXBEncoderDecoder.unmarshall(JAXBEncoderDecoder.java:908)
at org.apache.cxf.jaxb.JAXBEncoderDecoder.unmarshall(JAXBEncoderDecoder.java:712)

Answer 1

if (request.getSpeedInfo() == null || (request.getSpeedInfo() == null && request.getSpeedInfo().getBandwidth() == null)){

测试毫无意义getSpeedInfo()对于 null两次。这当然是显而易见的吗？这并没有测试 getBandwidth() 的情况单独为空。

根据您的要求:

1. If <speedInfo> itself is not present

request.getSpeedInfo() == null

2. <sch:SpeedInfo> is present, but bandwidth not present:

|| request.getSpeedInfo().getBandwidth() == null

3. Bandwidth is present but no value

|| request.getSpeedInfo().getBandwidth().isEmpty() // or whatever API call is appropriate to the datatype

把它们放在一起:

if (request.getSpeedInfo() == null
||
request.getSpeedInfo().getBandwidth() == null
||
request.getSpeedInfo().getBandwidth().isEmpty())
{
    // request is invalid
}
else
    // request is valid ...