java把一个字符串等段分割并转换成集合数组

package com.test.util;

import java.util.ArrayList;
import java.util.List;

public class StringTest {
    public static void main(String[] args) {
   String aa="dfgyhujiklredftghjklrdkldfghjklereedwefghjqwjkwfghjrk32er32t23de4rftgysdf";
        List<String> strList = getStrList(aa, 4);
        System.out.println(strList.toString());

    }

    /**
     *
     * @param inputString 需要分割字符串
     * @param length   分组长度
     * @return
     */
    public static List<String> getStrList(String inputString, int length) {
        int size = inputString.length() / length;
        if (inputString.length() % length != 0) {
            size += 1;
        }
        return getStrList(inputString, length, size);
    }

    public static List<String> getStrList(String inputString, int length, int size) {
        List<String> list = new ArrayList<String>();
        for (int index = 0; index < size; index++) {
            String childStr = substring(inputString, index * length, (index + 1) * length);
            list.add(childStr);
        }
        return list;
    }

    public static String substring(String str, int f, int t) {
        if (f > str.length())
            return null;
        if (t > str.length()) {
            return str.substring(f, str.length());
        } else {
            return str.substring(f, t);
        }
    }

}