JSON解析 null处理

使用的JSON包为json-lib-2.2.3-jdk15.jar。

需解析的JSON串：{"myCancerGenome":[],"aminoAcidChange":null,"normalRefCount":null,"ncbiBuildNo":"hg19","pdbLink":"","tumorType":null,"specialGeneData":null,"normalFreq":null,"mutationStatus":"Somatic","cna":"0","endPos":55273099,"geneSymbol":"EGFR","tumorFreq":null,"startPos":55273099,"keyword":"EGFR
T1141 missense","cosmic":null,"validationStatus":"Valid","normalAltCount":null,"mutationEventId":300276,"tumorAltCount":null,"functionalImpactScore":"M","tumorRefCount":null,"sequencingCenter":"WashU","igvLink":null}，其中有null也有""。

在解析上述JSON串的时候，控制台打印get("normalAltCount")结果为null,打印get("normalAltCount")==null的结果为false。百般无奈之下使用了getString("normalAltCount").equals("null")，控制台输出结果为true。

处理返回JSON数据的时候，null有可能是字符串的null。