如何使用Java RegEx匹配n次出现的表达式？
Java提供的贪婪量词使您可以匹配多次出现的表达式。哪里，
Exp{n}促使表达式exp恰好出现n次。
Exp{n，}促使表达式exp至少出现n次。
Exp{n，m}促使表达式exp至少出现n次，最多m次。
例子1
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class RegexExample {
public static void main( String args[] ) {
//正则表达式接受5个字母的单词
String regex = "\\w{5}";
Scanner sc = new Scanner(System.in);
System.out.println("Enter 5 input strings: ");
String input[] = new String[5];
for (int i=0; i<5; i++) {
input[i] = sc.nextLine();
}
//创建一个Pattern对象
Pattern p = Pattern.compile(regex);
for(int i=0; i<5;i++) {
//创建一个Matcher对象
Matcher m = p.matcher(input[i]);
if(m.find()) {
System.out.println(input[i]+": accepted");
} else {
System.out.println(input[i]+": not accepted");
}
}
}
}输出结果
Enter 5 input strings: rama raja raghu megha malya rama: not accepted raja: not accepted raghu: accepted megha: accepted malya: accepted
例子2
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class RegexExample {
public static void main( String args[] ) {
//正则表达式匹配长度为2到6的非单词字符串
String regex = "\\W{2,6}";
Scanner sc = new Scanner(System.in);
System.out.println("Enter 5 input strings: ");
String input[] = new String[5];
for (int i=0; i<5; i++) {
input[i] = sc.nextLine();
}
//创建一个Pattern对象
Pattern p = Pattern.compile(regex);
for(int i=0; i<5;i++) {
//创建一个Matcher对象
Matcher m = p.matcher(input[i]);
if(m.find()) {
System.out.println(input[i]+" matched");
}
}
}
}输出1
Enter 5 input strings: hello how are you #$#% # #$@%%#&#& sample text #$#% matched #$@%%#&#& matched
例子3
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class RegexExample {
public static void main(String args[] ) {
String regex = "[a-zA-Z]{1,20}";
Scanner sc = new Scanner(System.in);
System.out.println("输入学生姓名：");
String name = sc.nextLine();
Pattern p = Pattern.compile(regex);
Matcher m = p.matcher(name);
if(m.matches()) {
System.out.println("Name is appropriate");
} else {
System.out.println("Name is inappropriate");
}
}
}输出结果
输入学生姓名： Mouktika Name is appropriate