NPE預防小技巧

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防止NPE

Add Array Safely

Old Solution

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public static <E> void addAllIfNotNull(List<E> list, Collection<? extends E> c) {
    if (c != null) {
        list.addAll(c);
    }
}

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List<OcmImageData> listToBeAddedTo = new ArrayList<>();
addAllIfNotNull(listToBeAddedTo, listToBeAdded);

Java 8

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Optional.ofNullable(listToBeAdded).ifPresent(listToBeAddedTo::addAll)

String To Long

Apache commons的NumberUtils工具，
會檢核當input是null時返回指定值

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String strToBeConvert;
NumberUtils.toLong(strToBeConvert, 0L)

https://stackoverflow.com/a/49894716

Reference

https://stackoverflow.com/questions/30739105/any-null-safe-alternative-to-arraylist-addall
https://stackoverflow.com/questions/49894638/nullsafe-long-valueof