英文:
Sonar : Possible null pointer dereference due to return value of called method
问题
if (response != null && response.getBody() != null && response.getStatusCode() == HttpStatus.OK) {
return new BigDecimal(response.getBody());
}
我在上面的代码中因为调用方法的返回值可能为 null 而出现了可能的空指针解引用问题。
请问有人可以告诉我确切的问题是什么，以及为什么会是个问题呢？
response.getBody() // 返回一个字符串值
提前谢谢！如果需要任何其他细节，请告知。
英文:
if (response != null && response.getBody() != null && response.getStatusCode() == HttpStatus.OK) {
return new BigDecimal(response.getBody());
}
I am getting possible null pointer dereference due to return value of called method on above code.
Can someone please let me know the exact issue and why it's an issue?
response.getBody() // returns a string value
Thanks in advance! Please let me know if any other details are needed.
答案1
得分: 4
声纳不知道连续调用 getBody() 会返回相同的值。
因此，从静态分析器的角度来看，第二次调用有可能返回 null。
我建议将内容分配给一个本地变量，只调用一次获取器。这里 是来自声纳社区的参考，有人将此行为报告为错误并收到了类似的回应。
实际上，静态分析器无法证明这两个调用将返回相同的值，除非 response 是最终的不可变类型。我尝试过的静态分析器都没有办法去尝试证明这一点。
英文:
Sonar does not know that the two consecutive calls to getBody() will return the same value.
So, it is really possible, from the point of view of a static analyzer, that the second call returns null.
I'd recommend assigning the body to a local variable, and calling the getter only once. Here is a reference from Sonar community, where someone reported this behavior as bug and received a similar response.
A static analyzer actually cannot prove that the two calls will return the same value, unless response is of a final and immutable type. And no static analyzer I've tried yet goes to the length of trying to prove that.
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