java 姓名加密

String realname =  "程序员";
String mobile = "15888888888";    
String realname1 =null;
char[] r =  realname.toCharArray(); 
char[] m =  mobile.toCharArray();
if(r.length ==1){
  realname1 =  realname;
}
if(r.length == 2){
  realname1 =  realname.replaceFirst(realname.substring(1),"*");
}
if (r.length > 2) {
  realname1 =  realname.replaceFirst(realname.substring(1,r.length-1) ,"*");
}
for(int i=0; i<m.length;i++){
  if(i>2 && i<7){
      m[i] = '*';
  }
}
String mobile1 =  String.valueOf(m);
System.out.println(realname1);//程*员
System.out.println(mobile1);//158****8888