java统计字符串中各个字符的出现次数

package day16;
import java.util.*;
public class MapTest2 {


public static void main(String[] args) {
String str="lskkdjffjwekfmkdsasa";

countCharNum(str);


}
public static void countCharNum(String str){
TreeMap<Character,Integer> tm=new TreeMap<Character,Integer>();
char[] chs=str.toCharArray();
// int count=0;

for(int i=0;i<chs.length;i++){
Integer value=tm.get(chs[i]);
if(value==null)
tm.put(chs[i],1);
else
tm.put(chs[i], ++value);
}
 
Set<Character> keySet=tm.keySet();
Iterator<Character>  it=keySet.iterator();
while(it.hasNext()){
Character ch=it.next();
Integer value=tm.get(ch);
System.out.print(ch+"("+value+") ");
}
 
// System.out.println(tm);
}

}

//输出结果为：a(2) d(2) e(1) f(3) j(2) k(4) l(1) m(1) s(3) w(1)