正则表达式

public class Main {
    public static void main(String[] args) {
        /*
         * \d 表示任意一个数字 java用\\表示\ 
         * */
        String regex = "20\\d\\d";
        System.out.println("2019".matches(regex));
        System.out.println("2100".matches(regex));
    }
}

public class RegexDemo01 {
    public static void main(String[] args) {
        String re1 = "abc";
        System.out.println("abc".matches(re1)); // true
        System.out.println("Abc".matches(re1));// false
        System.out.println("abcd".matches(re1));//false
    }
}

public class RegexDemo02 {
    public static void main(String[] args) {
        String re1 = "java\\d"; //对应的是java\d
        System.out.println("java9".matches(re1)); //true
        System.out.println("java10".matches(re1));//false
        System.out.println("javac".matches(re1));//false
        String re2 = "java\\D";
        System.out.println("javax".matches(re2));//true
        System.out.println("java#".matches(re2));//ture
        System.out.println("java5".matches(re2));//false
    }
}

public class RegexDemo03 {
    public static void main(String[] args) {
        String re = "java|php";
        System.out.println("java".matches(re));//true
        System.out.println("php".matches(re));//true
        System.out.println("go".matches(re));//false
    }
}

public class RegexDemo04 {
    public static void main(String[] args) {
        String re = "learn\\s(java|php|go)"; // /s 匹配空格或tab
        System.out.println("learn java".matches(re));//true
        System.out.println("learn php".matches(re));//true
        System.out.println("learn go".matches(re));//true
    }
}

// 分组匹配
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class RegexDemo05 {
    public static void main(String[] args) {
        Pattern p = Pattern.compile("(\\d{3,4})\\-(\\d{7,8})");
        Matcher m = p.matcher("010-12345678");
        if (m.matches()) {
            String g1 = m.group(1);
            String g2 = m.group(2);
            System.out.println(g1);
            System.out.println(g2);
        } else {
            System.out.println("匹配失败！");
        }
    }
}

public class Main {
    public static void main(String[] args) {
        Pattern pattern = Pattern.compile("(\\d{3,4})\\-(\\d{7,8})");
        pattern.matcher("010-12345678").matches(); // true
        pattern.matcher("021-123456").matches(); // true
        pattern.matcher("022#1234567").matches(); // false
        // 获得Matcher对象:
        Matcher matcher = pattern.matcher("010-12345678");
        if (matcher.matches()) {
            String whole = matcher.group(0); // "010-12345678", 0表示匹配的整个字符串
            String area = matcher.group(1); // "010", 1表示匹配的第1个子串
            String tel = matcher.group(2); // "12345678", 2表示匹配的第2个子串
            System.out.println(area);
            System.out.println(tel);
        }