package everyDayPratise;import java.util.regex.Pattern;public class RegexExample{    public static void main(String[] args)    {        // 1. 美国身份证号        // 999-99-9999        // 999999999        Pattern p1 = Pattern.compile("[0-9]{3}\\-[0-9]{2}\\-[0-9]{4}");        Pattern p2 = Pattern.compile("\\d{3}\\-\\d{2}\\-\\d{4}");        Pattern p3 = Pattern.compile("[0-9]{3}\\-?[0-9]{2}\\-?[0-9]{4}");        Pattern p4 = Pattern.compile("\\d{3}\\-?\\d{2}\\-?\\d{4}");                // 2. 美国车牌号        // 4321AW        Pattern p5 = Pattern.compile("\\d{4}[A-Z]{2}");                // 3. x开头除外的的所有单词        Pattern p6 = Pattern.compile("[^x][a-z]*");    }}