关于Java中数组的常用操作方法

String[] arr1 = new String[5];
String[] arr2 = {"a","b","c", "d", "e"};
String[] arr3= new String[]{"a","b","c","d","e"};

int[] arr = { 1, 2, 3, 4, 5 };
String arrString = Arrays.toString(arr);

// 直接输出，为内存地址
System.out.println(arr);
// [I@139a55

System.out.println(arrString );
// [1, 2, 3, 4, 5]

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

//使用Apache Commons Lang library

1 int[] arr1 = { 1, 2, 3, 4, 5 };
2 int[] arr2= { 6, 7, 8, 9, 10 };
3 int[] combArr = ArrayUtils.addAll(arr1 , arr2);

// System.arraycopy()
1 static String[] concat(String[] a, String[] b) {
String[] c = new String[a.length + b.length];
System.arraycopy(a, 0, c, 0, a.length);
System.arraycopy(b, 0, c, a.length, b.length);
return c;
}

//Arrays.copyOf()

public static int[] concat(int[] first, int[] second) {
int[] result = Arrays.copyOf(first, first.length + second.length);
System.arraycopy(second, 0, result, first.length, second.length);
return result;
}

// Apache Commons Lang library

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

int[] arr = { 1, 2, 3, 4, 5 };
int[] revArr = new int[arr.length];
for(int i = 0; i < arr.length; i++){
revArr[i] = arr[arr.length - i -1];
}
System.out.println(Arrays.toString(revArr));

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

// Apache common lang

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