java - 在列表中输入几行

Question

我有简单的类(class):

public class ForStream {
   private int shortId;
   private long longId;

public ForStream(int shortId, long longId) {
    this.shortId = shortId;
    this.longId = longId;
}

public int getShortId() {
    return shortId;
}

public void setShortId(int shortId) {
    this.shortId = shortId;
}

public long getLongId() {
    return longId;
}

public void setLongId(long longId) {
    this.longId = longId;
}
}

需要找出数组中几个子串的出现。我这样做(可能无效):

  public static void main(String[] args) {
    List<ForStream> resList = List.of(
            new ForStream(689, 10000000001L),
            new ForStream(781, 10000000001L),
            new ForStream(785, 10000000001L),
            new ForStream(689, 10000000002L),
            new ForStream(689, 10000000003L),
            new ForStream(781, 10000000004L),
            new ForStream(785, 10000000004L)
    );

    boolean isEqual = !resList.stream()
            .filter(p -> p.getLongId() == 10000000001L)
            .filter(p -> p.getShortId() == 689)
            .filter(p -> p.getShortId() == 781)
            .filter(p -> p.getShortId() == 785)
            .collect(Collectors.toList()).isEmpty();

}

返回错误。但 689、781 和 785 包含列表。

Answer 1

这应该有效。您正在过滤掉单个元素。但是您想要做的是将它与值列表进行比较。你正在做的是 && 但你需要的是 ||

   boolean isEqual = !resList.stream()
                .filter(p -> p.getLongId() == 10000000001L)
                .filter(p -> Arrays.asList(689, 781, 785).contains(p.getShortId()))
                .collect(Collectors.toList()).isEmpty();