java中对字符串每个字符统计的方法

/*
    string name = "adsbsadgsadgtewterfsdf";
    eg a-->6,b-->1 d-->3 ...
    将字符串以a(字母)=>2(个数)存入map集合框架中
   思路:1.将字符串转换成字符数组.
          2.定义一个map集合,然后对字符数组进行遍历,如果map集合中没有该元素就将该元素存入map集合中,并定义一个计数器,将次数存入map中,来达到目的 

*/
import java.util.*;
class charmapdemo
{
    public static void main(string[] args)
    {
        string str = "abcedsadgsadfasdfaa";
        treemap<character,integer> tm = pross(str);
        system.out.println(tm);
    }
    public static treemap<character,integer> pross(string str)
    {
            char[] chararray = str.tochararray();

            treemap<character,integer> tm = new treemap<character,integer>();

            for (int x = 0; x < chararray.length ;x++ )
            {
                if(!tm.containskey(chararray[x]))
                {
                    tm.put(chararray[x],1);
                }
                else
                {
                    int count = tm.get(chararray[x])+1;
                    tm.put(chararray[x],count);
                }
            }
            return tm;
    }
}