字符串去重（hashSet）

public static String deleteRepeat(String strn){  
        String s=strn;
        String[] array = s.split(",");
        Set<String> staffsSet = new HashSet<>(Arrays.asList(array));
        String strappend="";
        for (String str : staffsSet) {  
            strappend+=str+",";
      }
        String newStr = strappend.toString().substring(0,strappend.length() - 1);
        return newStr;
    }