超实用的Java数组技巧攻略分享!

时间:2024-04-30 13:38:49

本文分享了关于Java数组最*的11大方法,帮助你解决工作流程问题,无论是运用在团队环境或是在私人项目中,你都可以直接拿来用!

  1. 声明一个数组(Declare an array)

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(Print an array in Java)

int[] intArray = { 1, 2, 3, 4, 5 };

String intArrayString = Arrays.toString(intArray);

// print directly will print reference value.

System.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(Create an ArrayList from an array)

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].

  1. 检查数组中是否包含特定值(Check if an array contains a certain value)

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( Concatenate two arrays)

int[] intArray = { 1, 2, 3, 4, 5 };

int[] intArray2 = { 6, 7, 8, 9, 10 };

// Apache Commons Lang library.

int[] combinedIntArray = ArrayUtils.addAll(intArray, intArray2);

  1. 声明一个数组内链(Declare an array inline )

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

  1. 将数组元素加入到一个独立的字符串中(Joins the elements of the provided array into a single String)

// containing the provided list of elements.

// Apache common lang.

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

System.out.println(j);

// a, b, c.

  1. 将数组列表转换成一个数组 (Covnert an ArrayList to an array)

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(Convert an array to a set)

Set<String> set = new HashSet<String>(Arrays.asList(stringArray));

System.out.println(set);

//[d, e, b, c, a].


9. 反向数组(Reverse an array)

int[] intArray = { 1, 2, 3, 4, 5 };

ArrayUtils.reverse(intArray);

System.out.println(Arrays.toString(intArray));

//[5, 4, 3, 2, 1].

  1. 删除数组元素(Remove element of an array)

int[] intArray = { 1, 2, 3, 4, 5 };

int[] removed = ArrayUtils.removeElement(intArray, 3);//create a new array.

System.out.println(Arrays.toString(removed));

One more – convert int to byte array

byte[] bytes = ByteBuffer.allocate(4).putInt(8).array();

for (byte t : bytes) {

System.out.format("0x%x ", t);

}