将字符串按固定长度分隔成子串

面试题：写一个函数，要求输入一个字符串和一个字符长度，对此字符串进行分隔。

/***
     * 将字符串按固定长度切割成字符子串
     * @param src 需要切割的字符串
     * @param length 字符子串的长度
     * @return 字符子串数组
     */
    public String[] splitStringByLength(String src, int length) {
        //检查参数是否合法
        if (null == src||src.equals("")) {
            System.out.println("the string is null");
            return null;
        }
        
        if (length <= 0) {
            System.out.println("the length < 0");
            return null;
        }
        
        System.out.println("now split "" + src + "" by length " + length);
        
        int n = (src.length() + length - 1) / length; //获取整个字符串可以被切割成字符子串的个数
        
        String[] split = new String[n];
        
        for (int i = 0; i < n; i++) {
            if (i < (n -1)) {
                split[i] = src.substring(i * length, (i + 1) * length);
            } else {
                split[i] = src.substring(i * length);
            }
        }
        
        return split;
    }

测试代码如下：

//测试代码
        String str = "hello world,this is my test program";
        SplitString splitString = new SplitString();
        String[] result = splitString.splitStringByLength(str, 6);
        for (int i = 0; i < result.length; i++) {
            System.out.println("subString" + i + ":" + result[i]);
        }

结果打印：
now split "hello world,this is my test program" by length 6
subString0:hello
subString1:world,
subString2:this i
subString3:s my t
subString4:est pr
subString5:ogram