catalogue
1. Introducing pom dependency
<!-- https://mvnrepository.com/artifact/org.apache.commons/commons-lang3 --> <dependency> <groupId>org.apache.commons</groupId> <artifactId>commons-lang3</artifactId> <version>3.11</version> </dependency>
2. Methods in ArrayUtils:
1.add(): adds the given data to the specified array and returns a new array.
2.addAll(): merge two arrays.
3.contains(): check whether the data exists in the array and return a boolean value.
4.getLength(): returns the length of the array.
5.indexOf(): query whether there is a specified value in the array from the first bit of the array. If there is a value that returns index, otherwise - 1 is returned.
6.lastIndexOf(): query whether there is a specified value in the array from the last bit of the array. If there is a value that returns index, otherwise - 1 is returned.
7.Insert(): add the specified element to the array at the specified position and return a new array.
8.isEmpty(): judge whether the array is empty and return a boolean value.
9.isNotEmpty(): judge whether the array is empty, not null.
10.isSameLength(): judge whether the lengths of two arrays are the same. When the array is empty, the length is 0. Returns a boolean value.
11.isSameType(): judge whether the types of two arrays are the same and return a boolean value.
12.isSorted(): judge whether the array is sorted in natural order and return a boolean value.
13.nullToEmpty():
14.remove(): delete the element at the specified position of the array and return a new array.
15.removeAll(): deletes the element at the specified position and returns a new array.
16. Removealloccurrences(): deletes the specified element from the array and returns a new array.
17.removeElement(): deletes the first occurrence of the specified element from the array and returns a new array.
18.removeElements(): delete the specified number of elements from the array and return a new array.
19.reverse(): array inversion. You can also specify the start and end reversal positions.
20.subarray(): intercepts the array (header but not tail) and returns a new array.
21.swap(): specify the element exchange of two positions of the array, or specify the length element of len after two positions.
22.toMap(): convert an array into a map and return a collection of map objects.
23.toObject(): converts an array of original data types into an array of object types.
24.toPrimitive(): convert the object type array to the original data type array.
25.toString(): output the array as Stirng and return a string.
26.toStringArray(): converts an Object array to a String array type.
3. Examples
public class ArraryTest {
public static void main(String[] args) {
int []array={4,5,9};
//The result of the add() method is: {4,5,9,6}
int[] newArray=ArrayUtils.add(array, 6);
System.out.println(ArrayUtils.toString(newArray));
//addAll() method, the result is: {4,5,9,5,9,6,7}
int []arrayAll={4,5,9};
int[] newArrayAll=ArrayUtils.addAll(arrayAll,5,9,6,7);
System.out.println(ArrayUtils.toString(newArrayAll));
//contains(): the result is: true, false
System.out.println(ArrayUtils.contains(arrayAll, 9));
System.out.println(ArrayUtils.contains(arrayAll, 3));
//getLength(): the result is 3
System.out.println(ArrayUtils.getLength(arrayAll));
//indexOf():2.
//indexOf(newArrayAll, 9,3):3 specifies which bit to start searching and returns the result 4
System.out.println(ArrayUtils.indexOf(newArrayAll, 9));
System.out.println(ArrayUtils.indexOf(newArrayAll, 9,3));
//The returned results of lastIndexOf() are 4 and 2
System.out.println(ArrayUtils.lastIndexOf(newArrayAll, 9));
System.out.println(ArrayUtils.lastIndexOf(newArrayAll, 9,3));
//insert(): the result is {4,5,3,9}
int [] arr=ArrayUtils.insert(2, arrayAll, 3);
System.out.println("insert"+ArrayUtils.toString(arr));
//isEmpty(): the result is false and true
int []a=null;
System.out.println(ArrayUtils.isEmpty(arr));
System.out.println(ArrayUtils.isEmpty(a));
//isNotEmpty(): the result is false and true
System.out.println("isNotEmpty:"+ArrayUtils.isNotEmpty(a));
System.out.println("isNotEmpty:"+ArrayUtils.isNotEmpty(arr));
//isSorted(): the result is false and true
int[]sort1={5,6,9,1};
int [] sort2={1,6,8,9};
System.out.println("sort1:"+ArrayUtils.isSorted(sort1));
System.out.println("sort2:"+ArrayUtils.isSorted(sort2));
//remove(): the returned result is {5,6,1}
int [] newRe=ArrayUtils.remove(sort1, 2);
for(int nr:newRe){
System.out.print(nr);
}
//reverse(): return new reverse:{1,9,6,5}
ArrayUtils.reverse(sort1);
System.out.println("new reverse:"+ArrayUtils.toString(sort1));
//subarray(): return result subarray:{3,9}
int[] sub={7,5,3,9,8,4};
int [] newsub=ArrayUtils.subarray(sub, 2, 4);
System.out.println("subarray:"+ArrayUtils.toString(newsub));
Object[] subs={7,5,3,9,8,4};
Map<Object, Object>map=ArrayUtils.toMap(subs);
}
}