package Test0914;
public class Mobile {
  public static void main(String[] args) {
    String mobile = "13856984571";
    mobile = mobile.replaceAll("(\\d{3})\\d{4}(\\d{4})", "$1****$2");
    System.out.println(mobile);
  }
}

138****4571

String.matches(regex)

String str = "abcdefefg";
String cmd = "<[^\\s]*>";
Pattern p = Pattern.compile(cmd);
Matcher m = p.matcher(str);
if(m.find()){
System.out.println(m.group());
}else{
System.out.println("not found");
}

String str="xingming:lsz,xingbie:nv";
String cmd="xingming:([a-zA-Z]*),xingbie:([a-zA-Z]*)"'
Pattern p = Pattern.compile(cmd);
Matcher m = p.matcher(str);
if(m.find()){
System.out.println("姓名："+m.group(1));
System.out.println("性别："+m.group(2));
}else{
System.out.println("not found");
}

String str= “abcaabadwewewe”;
String str2 = str.replaceAll("([a])([a]|[d])","*$2")
str2为：abc*ab*dwewewe