面试题: 请用代码来计算字符串"I'm go to swimming"中每一个字母出现的次数,并打印出来

package com.stephen;

import java.util.Iterator;
import java.util.Map;
import java.util.TreeMap;

/**
* 面试题: 请用代码来计算字符串"I'm go to swimming"中每一个字母出现的次数,并打印出来
*
* @author Administrator
*
*/
public class Test {

public static void main(String[] args) {

String str = "I'm go to swimming";

Test test = new Test();
// 得到一个字符数组

test.sortArr(test.getCharArr(str));

}

/**
* 将所有字符放入map集合中
*
* @param str
*/
Map<Character, Integer> getCharArr(String str) {
char[] arr = str.toCharArray();

Map<Character, Integer> map;

map = new TreeMap<>(); // 这里用的TreeMap,让它有序

for (int i = 0; i < arr.length; i++) {
if (arr[i] == ' ') {
continue;
}
int count = 1;
Integer integer = map.get(arr[i]);
if (integer != null) {
count = integer + count;
}
map.put(arr[i], count);
}
return map;
}

/**
* 遍历map
* 打印结果
*
* @param map
*/
void sortArr(Map<Character, Integer> map) {
Iterator<Character> iterator = map.keySet().iterator();

while (iterator.hasNext()) {
Character key = iterator.next();

Integer integer = map.get(key);

System.out.println(" " + key + "  | " + integer);

}
}
}