数组和列表的转换Java

数组和列表的转换-Java

• 数组—>列表：Array—>List
  List list = Arrays.asList(array)
• 列表—>数组：List—> Array
  Object[] array = list.toArray()

测试一:

获取数组的最大最小值

    @Test
    public void test10() {
        // 获取数组的最大最小值
        Integer[] array = {2, 3, 7, -3, 0, -5, 22, 8};

        int min = (int) Collections.min(Arrays.asList(array));
        int max = (int) Collections.max(Arrays.asList(array));

        System.out.println(min);
        System.out.println(max);
    }

-5
22

测试二：

合并两个数组

    @Test
    public void test11() {
        // 数组合并
        String[] str1 = {"a", "b", "c"};
        String[] str2 = {"d", "e"};

        // 先转换成List
        List list = new ArrayList(Arrays.asList(str1));
        list.addAll(Arrays.asList(str2));
        Object[] str3 = list.toArray();
        System.out.println(Arrays.toString(str3));
    }

[a, b, c, d, e]

测试三：

数组扩容

    @Test
    public void test12() {
        // 数组扩容
        String[] str = {"A", "B", "C"};
        String[] extended = new String[5];

        extended[3] = "D";
        extended[4] = "E";

        System.arraycopy(str, 0, extended, 0, str.length);
        System.out.println(Arrays.toString(extended));

    }

[A, B, C, D, E]