string split 的缺陷，",a,,"如何截取数组长度为4

public static String[] getStringArray(String s){

String b = s.replace(",", "','");

if(b.charAt(0)=='\''){

b = "'"+b;

}

if(b.charAt(b.length()-1)=='\''){

b = b + "'";

}

String[] str = b.split(",");

String[] new_str = new String[]{};

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

if(str[i].split("'").length>0){

new_str[i] = str[i].split("'")[1];

}else{

new_str[i] = str[i];

}

}

return new_str;

}