Java正则表达式程序，用于验证字符串是否包含至少一个字母数字字符。

以下正则表达式匹配包含至少一个字母数字字符的字符串-

"^.*[a-zA-Z0-9]+.*$";

哪里，

^。*匹配以零个或多个（任何）字符开头的字符串。

[a-zA-Z0-9]+匹配至少一个字母数字字符。

。*$匹配以零个或多个(ant)字符结尾的字符串。

例子1

import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String args[]) { //Reading String from user System.out.println("Enter a string"); Scanner sc = new Scanner(System.in); String input = sc.nextLine(); //Regular expression String regex = "^.*[a-zA-Z0-9]+.*$"; //Compiling the regular expression Pattern pattern = Pattern.compile(regex); //Retrieving the matcher object Matcher matcher = pattern.matcher(input); int count = 0; if(matcher.matches()) { System.out.println("Given string is valid"); } else { System.out.println("Given string is not valid"); } } }

输出1

Enter a string ###test123$$$ Given string is valid

输出2

Enter a string ####$$$$ Given string is not valid

例子2

import java.util.Scanner; public class Example { public static void main(String args[]) { //Reading String from user System.out.println("Enter a string"); Scanner sc = new Scanner(System.in); String input = sc.nextLine(); //Regular expression String regex = "^.*[a-zA-Z0-9]+.*$"; boolean result = input.matches(regex); if(result) { System.out.println("Valid match"); }else { System.out.println("In valid match"); } } }

输出1

Enter a string ###test123$$$ Valid match

输出2

Enter a string ####$$$$ In valid match