统计字符串中每个字符出现的次数

package first;

import java.util.Comparator;

import java.util.Scanner;

import java.util.Set;

import java.util.TreeMap;

public class map {

public static void main(String[] args) {

Scanner sc=new Scanner(System.in);

System.out.println(“please input”);

String line=sc.nextLine();//获得字符串

TreeMap《Character, Integer》 tm=new TreeMap《Character,Integer》();

char[] ch=line.toCharArray();

for (char c : ch) {

Integer i=tm.get(c);

if (i==null ) {

tm.put(c, 1);

}else {

i++;

tm.put(c, i);

}

}

StringBuilder sb=new StringBuilder();

Set set=tm.keySet();

for (Character key : set) {

Integer value=tm.get(key);

sb.append(key).append(“(“).append(value).append(“)”);

}

String ss=sb.toString();

System.out.println(ss);

}

}