获取String 中重复次数最多的字符

问题：获取String 中重复次数最多的字符，如果并列最多，返回任意一个。

代码如下：

测试类TestMain.java：

package com.test.string;

public class TestMain {

static String testString="abdcdkfgasfhuiejk jfdsfhusdfhaeh jjk";

public static void main(String[] args) {

System.out.println("hello world");

SearchMaxCharacterFromString TestString = new SearchMaxCharacterFromString();

Character c = TestString.getMaxChar(testString);

System.out.println("MaxChar:" + c);

}

}

实现类SearchMaxCharacterFromString.java：

package com.test.string;

import java.util.HashMap;

import java.util.Map;

import java.util.Map.Entry;

public class SearchMaxCharacterFromString {

private Map<Character, Integer> mMap = new HashMap<Character, Integer>();

public SearchMaxCharacterFromString() {

}

public Character getMaxChar(String mStr) {

Character result = null;

try {

Merger(mStr);

result = getResult();

} catch (Exception e) {

e.printStackTrace();

}

return result;

}

private void Merger(String s) throws NullPointerException {

for (int i = 0; i < s.length(); i++) {

char c = s.charAt(i);

if (mMap.containsKey(c)) {

mMap.put(c, mMap.get(c) + 1);

} else {

mMap.put(c, 1);

}

}

}

private Character getResult() throws NullPointerException {

Entry<Character, Integer> tmp = null;

for (Entry<Character, Integer> entry : mMap.entrySet()) {

Integer value = entry.getValue();

System.out.println(value);

System.out.println(entry.getKey());

if (tmp == null || value > tmp.getValue()) {

tmp = entry;

}

}

return tmp.getKey();

}

}

请各位帮忙看一下，上面的代码有什么地方还需要改进的，请直言，另外，以前是做C语言开发的，代码中或多或少会有一些C的思想，有没有什么办法可以摒弃这种思想。

可以在生成map的时候做个简单的优化，在等到一个字符的出现次数大于字符长度的1/2时就可以直接返回字符了，具体修改getMaxChar 和Merger方法即可。

public Character getMaxChar(String mStr) {

Character result = null;

try {

result = Merger(mStr);

if (result == null) {

result = getResult1();

}

} catch (Exception e) {

e.printStackTrace();

}

return result;

}

private Character Merger(String s) throws NullPointerException {

for (int i = 0; i < s.length(); i++) {

char c = s.charAt(i);

if (mMap.containsKey(c)) {

mMap.put(c, mMap.get(c) + 1);

if (mMap.get(c) > s.length() / 2) {

return c;

}

} else {

mMap.put(c, 1);

}

}

return null;

}