Java。 拆分列表每个元素的最佳方法

Question

How can I optimize this using streams?

    List<String> prepared = new ArrayList<>();
    availableFieldsFromImage.forEach(field -> {
        if(field.contains(".")){
            prepared.add(field.split("\\.")[0]);
        } else {
            prepared.add(field);
        }
    });

Answer 1

split returns the initial string if the delimiter is not found, so there is no need to test for "." before performing the split:

List<String> prepared = availableFieldsFromImage.stream()
                        .map(field -> field.split("\\.")[0])
                        .collect(Collectors.toList());

Answer 2

You can do:

List<String> prepared = availableFieldsFromImage.stream()
        .map(field -> field.contains(".") ? field.split("\\.")[0] : field)
        .collect(Collectors.toList());

Answer 3

maybe

    List<String> prepared=availableFieldsFromImage.stream()
.map(i->i.contains(".") ? i.split("\\.")[0] : i)
.collect(Collectors.toList())

Answer 4

Use a map and then collect

availableFieldsFromImage.stream().map(field -> field.contains(".") 
                                        ? field.split("\\.")[0] 
                                        : field)
                        .collect(Collectors.toList());