通过使用正则表达式在Java中输入密码
我正在尝试使用正则表达式生成密码,但我不明白为什么我的代码不起作用:通过使用正则表达式在Java中输入密码,java,regex,passwords,Java,Regex,Passwords,我正在尝试使用正则表达式生成密码,但我不明白为什么我的代码不起作用: import java.util.Scanner; class test { public static void main (String[] args) { Scanner scanner = new Scanner(System.in); System.out.println("Enter a password please."); String password = scann
import java.util.Scanner;
class test {
public static void main (String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.println("Enter a password please.");
String password = scanner.nextLine();
int x;
String redex = "(^[0-9]+$)";
String redexx = "(^[A-Z]+$)";
boolean hasSpace = false;
boolean hasUpperCase = false;
boolean hasLetter = false;
boolean hasDigit = false; // we set four booleans to be able to bring up individual error messages.
if (password.length() > 8){
hasLetter = true;
} else {
System.out.println("Your password needs to be at least 8 characters long.");
if (password.matches(redexx)) { // we check to see if the password has at least an upper case letter, one or more digits and a space using regular expressions
hasUpperCase = true;
} if (password.matches(redexx)) {
hasDigit = true;
} if (password.indexOf(' ') == 1) {
hasSpace = true; }
} if (hasLetter && hasDigit && hasUpperCase && !hasSpace) {
System.out.println("Your password is strong.");
} if (!hasDigit) {
System.out.println("You need to put numbers in your password.");
} if (!hasUpperCase) {
System.out.println("You need to use an upper case letter in your password.");
} if (hasSpace) {
System.out.println("You need to delete any spaces in your password.");
} // if we use if statements (and not any "else" or "else if", we get to show all the possible error messages.
}
}
在更正了“regex”和“regexx”之后,在编译之后,当我输入一个完全适用的密码时,它仍然会显示密码需要大写,也需要数字问题可能是因为您没有将“regex”放在引号中。它们是弦 试试看:
String redex = "(^[0-9]+$)";
String redexx = "(^[A-Z]+$)";
试试这个:
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.println("Enter a password please.");
String password = scanner.nextLine();
boolean validLength = password.length() >= 8;
boolean hasLetter = password.matches(".*[a-zA-Z].*");
boolean hasDigit = password.matches(".*\\d.*");
boolean hasSpace = password.matches(".*\\s.*");
if (!validLength)
System.out.println("The password must be at least 8 characters long.");
else if (!hasLetter)
System.out.println("The password must contain at least one letter.");
else if (!hasDigit)
System.out.println("The password must contain at least one digit.");
else if (hasSpace)
System.out.println("The password must not contain spaces.");
else
System.out.println("Your password is strong.");
}
}
除了问题注释中提到的错误之外,您还使用了不正确的正则表达式。有关如何在Java中使用正则表达式的信息,请阅读
此外,空格字符实际上使密码更强大,因此我建议允许用户输入空格字符。在我的答案的演示代码中,用户不允许输入空格字符,因为这是您的要求。您是指正则表达式吗?您理解为什么这些行不编译吗?字符串redex=(^[0-9]+$);字符串redexx=(^[A-Z]+$)
password.length()>8
表示密码必须至少为9个字符才能通过该测试,而不是在您稍后写3行时为8个字符。说明“我的代码不工作”的问题必须包括它不工作的原因,以及发生的任何错误,包括编译错误(如果不工作的代码不编译)。您可以只使用一个正则表达式并根据匹配返回一个命名组,然后使用switch语句将组的名称与每个大小写进行比较,以返回一个适当的值:^(?((((?{0,7})|)(?..*)|(?\D*)(?[^\v\p{Lu}*)|(?[^\v\p{Ll}]*))|((?。{8,}))$/code>。注意:第一个条目是唯一有效的密码,其他所有条目均不符合您的规范。这可能不是最好的答案,但它确实用最少的代码解决了手头的问题。