用Java写一个算法,把一串数字,所有可能的和按顺序排列,并计算每个和出现的次数

应你的要求 我只做了加一位的和加两位的
算法类代码如下:
public class CountSumClass {
private String number;
private String result = new String("");
public CountSumClass() {
number = new String();
}
public CountSumClass(String str) {
number = str;
}
public String getResult() {
return result;
}
public void addOne() {
int x,y;
for (int i = 0; i < number.length()-1; i++) {
x = (int)number.charAt(i) - 48;
for(int j = i+1; j