Java eqivalent method of “splice(a，b,..）“在 JavaScript 方法中

这是根据JavaScript MDN规范的Array.prototype.splice()方法的Java实现。

  public static <T>T[] splice(final T[] array, int start) {
    if (start < 0)
      start += array.length;
    return splice(array, start, array.length - start);
  }
  @SuppressWarnings("unchecked")
  public static <T>T[] splice(final T[] array, int start, final int deleteCount) {
    if (start < 0)
      start += array.length;
    final T[] spliced = (T[])Array.newInstance(array.getClass().getComponentType(), array.length - deleteCount);
    if (start != 0)
      System.arraycopy(array, 0, spliced, 0, start);
    if (start + deleteCount != array.length)
      System.arraycopy(array, start + deleteCount, spliced, start, array.length - start - deleteCount);
    return spliced;
  }
  @SuppressWarnings("unchecked")
  public static <T>T[] splice(final T[] array, int start, final int deleteCount, final T ... items) {
    if (start < 0)
      start += array.length;
    final T[] spliced = (T[])Array.newInstance(array.getClass().getComponentType(), array.length - deleteCount + items.length);
    if (start != 0)
      System.arraycopy(array, 0, spliced, 0, start);
    if (items.length > 0)
      System.arraycopy(items, 0, spliced, start, items.length);
    if (start + deleteCount != array.length)
      System.arraycopy(array, start + deleteCount, spliced, start + items.length, array.length - start - deleteCount);
    return spliced;
  }

以下 JUnit 代码测试此实现：

@Test
  public void testSplice() {
    final String[] array = new String[] {"a", "b", "c", "d", "e", "f"};
    Assert.assertArrayEquals(new String[] {"c", "d", "e", "f"}, Arrays.splice(array, 0, 2));
    Assert.assertArrayEquals(new String[] {"a", "d", "e", "f"}, Arrays.splice(array, 1, 2));
    Assert.assertArrayEquals(new String[] {"a", "b", "e", "f"}, Arrays.splice(array, 2, 2));
    Assert.assertArrayEquals(new String[] {"a", "b", "c", "f"}, Arrays.splice(array, 3, 2));
    Assert.assertArrayEquals(new String[] {"a", "b", "c", "d"}, Arrays.splice(array, 4, 2));
    try {
      Arrays.splice(array, 5, 2);
      Assert.fail("Expected ArrayIndexOutOfBoundsException");
    }
    catch (final ArrayIndexOutOfBoundsException e) {
    }
    try {
      Arrays.splice(array, -2, 3);
      Assert.fail("Expected ArrayIndexOutOfBoundsException");
    }
    catch (final ArrayIndexOutOfBoundsException e) {
    }
    Assert.assertArrayEquals(new String[] {"a", "b", "c", "d"}, Arrays.splice(array, -2, 2));
    Assert.assertArrayEquals(new String[] {"a", "b", "c", "f"}, Arrays.splice(array, -3, 2));
    Assert.assertArrayEquals(new String[] {"a", "b", "e", "f"}, Arrays.splice(array, -4, 2));
    Assert.assertArrayEquals(new String[] {"a", "d", "e", "f"}, Arrays.splice(array, -5, 2));
    Assert.assertArrayEquals(new String[] {"c", "d", "e", "f"}, Arrays.splice(array, -6, 2));
    try {
      Arrays.splice(array, -7, 2);
      Assert.fail("Expected ArrayIndexOutOfBoundsException");
    }
    catch (final ArrayIndexOutOfBoundsException e) {
    }
    Assert.assertArrayEquals(new String[] {}, Arrays.splice(array, 0));
    Assert.assertArrayEquals(new String[] {"a"}, Arrays.splice(array, 1));
    Assert.assertArrayEquals(new String[] {"a", "b"}, Arrays.splice(array, 2));
    Assert.assertArrayEquals(new String[] {"a", "b", "c"}, Arrays.splice(array, 3));
    Assert.assertArrayEquals(new String[] {"a", "b", "c", "d"}, Arrays.splice(array, 4));
    Assert.assertArrayEquals(new String[] {"a", "b", "c", "d", "e"}, Arrays.splice(array, 5));
    Assert.assertArrayEquals(new String[] {"a", "b", "c", "d", "e", "f"}, Arrays.splice(array, 6));
    try {
      Arrays.splice(array, 7);
      Assert.fail("Expected ArrayIndexOutOfBoundsException");
    }
    catch (final ArrayIndexOutOfBoundsException e) {
    }
    Assert.assertArrayEquals(new String[] {"a", "b", "c", "d", "e"}, Arrays.splice(array, -1));
    Assert.assertArrayEquals(new String[] {"a", "b", "c", "d"}, Arrays.splice(array, -2));
    Assert.assertArrayEquals(new String[] {"a", "b", "c"}, Arrays.splice(array, -3));
    Assert.assertArrayEquals(new String[] {"a", "b"}, Arrays.splice(array, -4));
    Assert.assertArrayEquals(new String[] {"a"}, Arrays.splice(array, -5));
    Assert.assertArrayEquals(new String[] {}, Arrays.splice(array, -6));
    try {
      Arrays.splice(array, -7);
      Assert.fail("Expected NegativeArraySizeException");
    }
    catch (final NegativeArraySizeException e) {
    }
    Assert.assertArrayEquals(new String[] {"x", "y", "z", "c", "d", "e", "f"}, Arrays.splice(array, 0, 2, "x", "y", "z"));
    Assert.assertArrayEquals(new String[] {"a", "x", "y", "z", "d", "e", "f"}, Arrays.splice(array, 1, 2, "x", "y", "z"));
    Assert.assertArrayEquals(new String[] {"a", "b", "x", "y", "z", "e", "f"}, Arrays.splice(array, 2, 2, "x", "y", "z"));
    Assert.assertArrayEquals(new String[] {"a", "b", "c", "x", "y", "z", "f"}, Arrays.splice(array, 3, 2, "x", "y", "z"));
    Assert.assertArrayEquals(new String[] {"a", "b", "c", "d", "x", "y", "z"}, Arrays.splice(array, 4, 2, "x", "y", "z"));
    try {
      Arrays.splice(array, 5, 2, "x", "y", "z");
      Assert.fail("Expected ArrayIndexOutOfBoundsException");
    }
    catch (final ArrayIndexOutOfBoundsException e) {
    }
    Assert.assertArrayEquals(new String[] {"a", "b", "c", "d", "x", "y", "z"}, Arrays.splice(array, -2, 2, "x", "y", "z"));
    Assert.assertArrayEquals(new String[] {"a", "b", "c", "x", "y", "z", "f"}, Arrays.splice(array, -3, 2, "x", "y", "z"));
    Assert.assertArrayEquals(new String[] {"a", "b", "x", "y", "z", "e", "f"}, Arrays.splice(array, -4, 2, "x", "y", "z"));
    Assert.assertArrayEquals(new String[] {"a", "x", "y", "z", "d", "e", "f"}, Arrays.splice(array, -5, 2, "x", "y", "z"));
    Assert.assertArrayEquals(new String[] {"x", "y", "z", "c", "d", "e", "f"}, Arrays.splice(array, -6, 2, "x", "y", "z"));
    try {
      Arrays.splice(array, -7, 2, "x", "y", "z");
      Assert.fail("Expected ArrayIndexOutOfBoundsException");
    }
    catch (final ArrayIndexOutOfBoundsException e) {
    }
  }

编辑：正如@denys-séguret正确指出的那样，此实现与JavaScript规范不同，因为它不会改变/修改原始数组。相反，此实现返回一个新的数组实例。

编辑：此实现在给定的 maven 存储库中可用于以下 maven 工件：

<project>
  ...
  <dependencies>
    <dependency>
      <groupId>org.safris.commons</groupId>
      <artifactId>commons-lang</artifactId>
      <version>1.6.4</version>
    </dependency>
  </dependencies>
  ...
  <repositories>
    <repository>
      <id>mvn.repo.safris.org</id>
      <url>http://mvn.repo.safris.org/m2</url>
    </repository>
  </repositories>
  ...
</project>

Java 数组有固定的长度，所以没有这样的方法。

你可以想象在 Java 中编写一个类似于拼接的实用程序函数，但它会返回一个不同的数组。如果你调整数组的大小，在java中拥有数组是没有意义的：它效率低下，你不能共享实例。

通常且干净的解决方案是使用 List，这是一个可调整大小的集合。ArrayList 是最常用的 List 实现，由数组支持，但效率很高，因为每次调整集合大小时都不会更改数组。

在标准 Java 库中，没有等效的功能。

有java.util.Arrays类，但没有类似的功能。

Java 数组具有固定长度，因此不能直接执行此操作。

如果你想组合两个数组，看看这个答案。

如果要添加到数组中，则应改用List或ArrayList。

我误读了你的问题，混淆了splice和slice.

类 java.util.Arrays 提供了一些在使用数组时有用的静态函数。有关其他功能，请参阅官方文档：http://docs.oracle.com/javase/8/docs/api/java/util/Arrays.html。

Java对slice的等价物是：Arrays.copyOfRange(array, from, to)。

与splice类似的方法是addAll（http://docs.oracle.com/javase/8/docs/api/java/util/ArrayList.html#addAll-int-java.util.Collection-）。但是您需要使用java.util.ArrayList而不是数组，并且无法使用它删除元素。您必须将这些元素作为另一个集合提供，例如ArrayList。所以相当于叫splice(index, 0, element1, element2, ...)

Java 中的数组具有固定数量的元素。但是你可以像这样使该元素为空：

数组[元素]==空;

这与将其从数组中删除相同。你也可以有一个变量来跟踪有多少元素不是空的，这样你甚至可以有一个 array.length 之类的东西。反正我就是这么做的。