密码验证(8个字母，2个数字，无符号)

Question

import java.awt.Component;

import javax.swing.JOptionPane;

public class DoSomething {
public static void main(String[] args) {
String password = JOptionPane.showInputDialog(null, 
"Please enter a password: "); 

    boolean number = false; 
    boolean character = false; 
    boolean symbol = false; 
    boolean length = false; 
    Component frame = null; 
    int counter = 0; 
char [] letters = password.toCharArray(); 
for (char c: letters){

if(Character.isLetter(c)) {
    if (password.matches("a-zA-Z")) {
        counter++;
        character= true;
    }
}
if(Character.isLetterOrDigit(c)) {
    counter++;
    symbol = false;
}
if(Character.isDigit(c)) {
    counter++; 
    if (counter >=2) {
        number = true;
    }
 if (password.length()>=8) {
    length = true;
        }

if (character && length && number && !symbol){
 JOptionPane.showMessageDialog("Your Password " +password +" is valid")
 }
}
}

编辑 - 它仍然讨厌长度（即使是8个或更多）

Answer 1

为什么不使用正则表达式？

public static boolean isValid(String password) {
    return password.matches("([a-zA-Z]{8,})([0-9]{2,})");
}

此表达式（如果我没记错的话）检查是否有8个或更多字符（小写和大写）和如果密码中有两个以上的数字。$， @，[space]之类的符号会触发表达式为false。编辑：此正则表达式仅允许使用8个（或更多）分组字符和2个（或更多）号码的密码。数字不能分开（1mypassword3），因为这会将密码标记为无效。需要进一步调查。

有关正则表达式请参见Java API：

Java 7模式类

Java 8模式类

还请查看String.Matches（String Regex）

评论反应

此代码应该更适合您：

int letterCount = 0;
int numberCount = 0;
/*
 * Loop through the password and count all the letters and characters
 */
for (int i = 0; i < password.length(); i++) {
    char c = password.charAt(i);
    if (Character.toString(c).matches("[a-zA-Z]")) {
        letterCount++;
    }
    if (Character.toString(c).matches("[0-9]")) {
        numberCount++;
    }
}

if (letterCount > 8) {
    // password has 8 or more characters
}
if (numberCount > 2) {
    // password has more than 2 numbers
}

然后，如果您也确实想检查长度，则可以添加此代码（在循环外）

if (password.length() >= 10) {
    /* Since we need 2 numbers and 8 characters, the password
     * can never be valid if it's smaller than 10 characters
     */
else {
    /*
     * Invalid password
     */
} 

Answer 2

假设您的有效密码条件为：

• 至少8个字母
• 至少2个数字
• 没有符号

• 至少10个字符长

String password = JOptionPane.showInputDialog(null, "Please enter a password: "); 
boolean number = false; 
boolean character = false; 
boolean symbol = false; 
boolean length = false;  
int letterCounter = 0; 
int numCounter = 0;
Component frame = null; 
char [] letters = password.toCharArray(); 
for (char c: letters){
    if(Character.isLetter(c)) {
        letterCounter++;
    }
    else if(Character.isDigit(c)) {
        numCounter++;
    }
    else {
        symbol = true;
    }
}
//Checking booleans
if (password.length()>=10) {
    length = true;
}
if (letterCounter>=8) {
    character = true;
}
if (numCounter>=2) {
    number = true;
}
if (character && length && number && !symbol){
    JOptionPane.showMessageDialog(frame, "Your Password " + password + " is valid");
    System.out.println("Success");
}
else {
    System.out.println("Invalid");
}