吶，讓我們先創建一個數組吧。

String[] a = new String[5];
String[] b = {“a”,”b”,”c”, “d”, “e”};
String[] c = new String[]{“a”,”b”,”c”,”d”,”e”};

1.打印數組

我們經常使用for循環或者一些迭代器來打印出數組的所有元素，但我們也可以換個姿勢。

int array[] = {1,2,3,4,5};
System.out.println(array); //[I@1234be4e
String arrStr = Arrays.toString(array);
System.out.println(array); //[1,2,3,4,5];

2.創建ArrayList

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

3.檢查是否包含某個值

int array[] = {1,2,3,4,5};
boolean isContain= Arrays.asList(array).contains(5);
System.out.println(isContain);
// true

4.連接兩個數組

int[] array1 = { 1, 2, 3, 4, 5 };
int[] array2 = { 6, 7, 8, 9, 10 };
// Apache Commons Lang library
int[] combinedIntArray = ArrayUtils.addAll(array1, array2);

5.在一行聲明一個數組

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

6.數組倒置

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

7.刪除某個元素

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

8.轉化為set

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

9.將ArrayList轉化為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);

10.將數組元素組成一個字符串

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