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