用java如何将一个字符串string=“aaabbbcccdddd”，输出为：aaa,bbb,ccc,ddd

String[] str1 = {"aaa","bbb","ccc"};
String[] str2 = {"bbb","ddd"};
String[] str3 = {"eee","fff"};
//运算开始：
Map isH = new HashMap();
for(String s:str1){
if(isH.get(s)==""){continue;}
isH.put(s,"");
}
for(String s:str2){
if(isH.get(s)==""){continue;}
isH.put(s,"");
}
for(String s:str3){
if(isH.get(s)==""){continue;}
isH.put(s,"");
}
String[] toStr = (String[])isH.keySet().toArray();

string str="aaabbbcccddd";
char[] stringArr = str.toCharArray();
for (int i = 0; i < 4; i++)
{
string strs = null;
for (int j = i*3; j < (i+1)*3; j++)
{
strs += stringArr[j];
}
system.out.printf(strs);
}