[javaSE笔记8]System类 StringBuilder

System类

几个常用方法 :

1. arraycopy方法

        int[] src = {1,2,3,4,5};
        int[] dest = {6,7,8,9,10};
        System.out.println(Arrays.toString(dest));
        System.arraycopy(src, 0, dest, 0, 3);
        System.out.println(Arrays.toString((dest)));


/* out : 
[6, 7, 8, 9, 10]
[1, 2, 3, 9, 10]
*/