Java8 在流处理中使用集合索引号

代码

public class AnswerApp {
    public static void main(String[] args) {
        List<String> list = Lists.newArrayList("Answer", "AnswerAIL", "AI");
        List<String> result1 = list.stream().map(e -> "Prev-" + e).collect(Collectors.toList());
        System.out.println(result1);

        List<Entity> result2 = IntStream.range(0, list.size()).mapToObj(i -> new Entity(i, list.get(i))).collect(Collectors.toList());
        System.out.println(result2);
    }
}

@Data
@AllArgsConstructor
class Entity {
    private Integer index;
    private String data;
}

程序运行输出

[Prev-Answer, Prev-AnswerAIL, Prev-AI]
[Entity(index=0, data=Answer), Entity(index=1, data=AnswerAIL), Entity(index=2, data=AI)]