合并两个数组的几种方式

import org.junit.Test;

import java.util.Arrays;

/**
 * @Description: ArrayUtils.addAll();System.arrayCopy();Arrays.copyOf();
 * @date: 2020-08-12 18:40
 * @author: yff
 */
public class ArrayMergeTest {

    private final int a;

    public ArrayMergeTest() {
        this.a = 5;
    }

    @Test
    public void main() {
        Integer[] integers1 = {3, 1, 2};
        Integer[] integers2 = {9, 7, 10};


/*      //method one
        Integer[] integersAll = (Integer[]) ArrayUtils.addAll(integers1, integers2);
*/

/*
        //method two
        Integer[] integersAll = new Integer[integers1.length + integers2.length];
        System.arraycopy(integers1, 0, integersAll, 0, integers1.length);
        System.arraycopy(integers2, 0, integersAll, integers1.length, integers2.length);
*/


        //method three
        Integer[] integersAll = Arrays.copyOf(integers1, integers1.length + integers2.length);
        System.arraycopy(integers2, 0, integersAll, integers1.length, integers2.length);


        Arrays.sort(integersAll);
        for (Integer o : integersAll) {
            System.out.println(o);
        }
    }

}