【Java基础】arraycopy

最近看到java的arraycopy挺好用的，快速复制数组内容到另一个数组里面
arraycopy(源数组，原数组的起始位置，目标数组，目标数组的起始位置，源数组的可复制的长度)

public class ACDemo {
    static byte a[] = { 65, 66, 67, 68, 69, 70, 71, 72, 73, 74 };
    static byte b[] = { 77, 77, 77, 77, 77, 77, 77, 77, 77, 77 };

    public static void main(String[] args) {
        //
        System.out.println("a = " + new String(a));
        System.out.println("b = " + new String(b));
        System.arraycopy(a, 0, b, 0, a.length);
        System.out.println("a = " + new String(a));
        System.out.println("b = " + new String(b));
        System.arraycopy(a, 0, a, 1, a.length-1);
        System.arraycopy(b, 1, b, 0, b.length - 1);
        System.out.println("a = " + new String(a));
        System.out.println("b = " + new String(b));
    }
}

arraycopy 比 java循环快很多，用这个比较方便

输出结果

a = ABCDEFGHIJ
b = MMMMMMMMMM
a = ABCDEFGHIJ
b = ABCDEFGHIJ
a = AABCDEFGHI
b = BCDEFGHIJJ