nullPointerException除非e.getKey()返回,否则下面的代码会得到吗nullMap<Integer, Optional<SecurityAttributeChange>> spnCreationDetails;Optional.ofNullable(spnCreationDetails.get(e.getKey()).orElse(new SecurityAttributeChange()).getNewAttribute()) .orElse(new SecurityAttr()) .getUserName());我在这一行中遇到了 NPE,是否可以调试它?我知道spnCreationDetails.get(e.getKey())返回 null,我null在这里处理时遗漏了什么吗?- 编辑这是几乎完整的方法,它将有助于提供有关如何重构它以使其可读的输入。private void updateAuditFields(List<SecurityAttributeChange> securityChanges, Map<Integer, Map<String, Object>> result) { Map<Integer, Optional<SecurityAttributeChange>> spnModificationDetails = ... Map<Integer, Optional<SecurityAttributeChange>> spnCreationDetails = ... result.entrySet().stream().forEach(e -> { e.getValue() .put("userIdLastChanged", Optional.ofNullable(Optional.ofNullable(spnModificationDetails.get(e.getKey())) .orElse(Optional.of(new SecurityAttributeChange())) .get() .getNewAttribute()).orElse(new SecurityAttr()).getUserName()); e.getValue() .put("lastChangedDatetime", Optional.ofNullable(Optional.ofNullable(spnModificationDetails.get(e.getKey())) .orElse(Optional.of(new SecurityAttributeChange())) .get() .getNewAttribute()).orElse(new SecurityAttr()).getKnowledgeBeginDate()); e.getValue() .put("userIdCreated", Optional.ofNullable( Optional.ofNullable(spnCreationDetails.get(e.getKey())).orElse(Optional.of(new SecurityAttributeChange())).get().getNewAttribute()) .orElse(new SecurityAttr()) .getUserName()); });}
1 回答

泛舟湖上清波郎朗
TA贡献1818条经验 获得超3个赞
如果spnCreationDetails.get(e.getKey())
可以为空,您可能需要:
Optional.ofNullable(spnCreationDetails.get(e.getKey())) .orElse(new SecurityAttributeChange()) .getNewAttribute() .orElse(new SecurityAttr()) .getUserName();
iespnCreationDetails.get(e.getKey())
应该用Optional
.
编辑:看到您的评论,spnCreationDetails.get(e.getKey())
可以返回 anull
或 an Optional<SecurityAttributeChange>
,因此最好只将 thenull
转换为 new Optional
:
spnCreationDetails.getOrDefault(e.getKey(),Optional.empty()) .orElse(new SecurityAttributeChange()) .getNewAttribute() .orElse(new SecurityAttr()) .getUserName();
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