剑指offer三十一之连数中1出现的次数（从1到n整数中1出现的次数

public class Solution {
    public int NumberOf1Between1AndN_Solution(int n) {
        int count=0;
        StringBuffer stringBuffer = new StringBuffer();
        //所有数字变成字符串
        for (int i = 1; i <= n; i++) {
            stringBuffer.append(i);
        }
        //统计字符串中‘1’的个数
        for(int j=0;j){
            if(stringBuffer.charAt(j)=='1'){
                count++;
            }
        }

        //返回结果
        return count;
    }
}