Java数组技巧

来源:互联网 发布:淘宝客服怎么要好评 编辑:程序博客网 时间:2024/05/18 02:04

0.  声明一个数组

String[] aArray = new String[5];String[] bArray = {"a","b","c", "d", "e"};String[] cArray = new String[]{"a","b","c","d","e"};

1.  在Java中输出一个数组

int[] intArray = { 1, 2, 3, 4, 5 };String intArrayString = Arrays.toString(intArray);  // print directly will print reference valueSystem.out.println(intArray);// [I@7150bd4d  System.out.println(intArrayString);// [1, 2, 3, 4, 5]


2. 从数组中创建数组列表

String[] stringArray = { "a", "b", "c", "d", "e" };ArrayList<String> arrayList = new ArrayList<String>(Arrays.asList(stringArray));System.out.println(arrayList);// [a, b, c, d, e]

3. 检查数组中是否包含特定值

String[] stringArray = { "a", "b", "c", "d", "e" };boolean b = Arrays.asList(stringArray).contains("a");System.out.println(b);// true

4. 连接两个数组

int[] intArray = { 1, 2, 3, 4, 5 };int[] intArray2 = { 6, 7, 8, 9, 10 };int[] combinedIntArray = ArrayUtils.addAll(intArray, intArray2);

5. 声明一个数组内链

method(new String[]{"a", "b", "c", "d", "e"});

6. 将数组元素加入到一个独立的字符串中

String j = StringUtils.join(new String[] { "a", "b", "c" }, ", ");System.out.println(j);// a, b, c

7. 将数组列表转换成一个数组 

String[] stringArray = { "a", "b", "c", "d", "e" };ArrayList<String> arrayList = new ArrayList<String>(Arrays.asList(stringArray));String[] stringArr = new String[arrayList.size()];arrayList.toArray(stringArr);for (String s : stringArr)    System.out.println(s);

8. 将数组转换成一个集合

Set<String> set = new HashSet<String>(Arrays.asList(stringArray));System.out.println(set);//[d, e, b, c, a]

9. 反向数组

int[] intArray = { 1, 2, 3, 4, 5 };ArrayUtils.reverse(intArray);System.out.println(Arrays.toString(intArray));//[5, 4, 3, 2, 1]

10. 删除数组元素

int[] intArray = { 1, 2, 3, 4, 5 };int[] removed = ArrayUtils.removeElement(intArray, 3);System.out.println(Arrays.toString(removed));

11. 数组转化为流

byte[] bytes = ByteBuffer.allocate(4).putInt(8).array();  for (byte t : bytes) {   System.out.format("0x%x ", t);}