英文:
how can I put null check in conditional block when using optional in java?
问题
这是代码：
Optional<Buyer> buyerOptional = Optional.ofNullable(buyerRepository.findById(buyerId).orElse(null));
Buyer buyer = buyerOptional.get();
if (buyer != null) {
} else if (buyerOptional == null) {
response = utility.createResponse(500, KeyWord.ERROR, "无效的买家");
}
我想进入else if块中，如果能够提供任何建议，将会很有帮助。
英文:
this is the code
Optional<Buyer> buyerOptional = Optional.ofNullable(buyerRepository.findById(buyerId).orElse(null));
Buyer buyer = buyerOptional.get();
if (buyer != null) {
} else if (buyerOptional == null) {
response = utility.createResponse(500, KeyWord.ERROR, "Invalid buyer");
}
I want to get inside else if block, would be great if I could get any suggestion on this.
答案1
得分: 2
首先，您无需再创建Optional，因为findById已经返回了Optional。您可以使用isPresent()来检查值是否存在。
Optional<Buyer> buyerOptional = buyerRepository.findById(buyerId);
if (buyerOptional.isPresent()) {
Buyer buyer = buyerOptional.get();
... // 准备响应数据
} else {
response = utility.createResponse(500, KeyWord.ERROR, "无效的买家");
}
英文:
First of all, you don't need to create Optional again as findById already return Optional. And you can use isPresent() to check if value present or not.
Optional<Buyer> buyerOptional = buyerRepository.findById(buyerId);
if (buyerOptional.isPresent()) {
Buyer buyer = buyerOptional.get();
... // preparing response
} else {
response = utility.createResponse(500, KeyWord.ERROR, "Invalid buyer");
}
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