Java의 보안 프로그래밍: Java에 내장된 보안 기능을 사용하는 방법은 무엇입니까?

public class MyClass {
    private String name;  // 私有成员变量
    public void setName(String name) { this.name = name; }  // 公共设置器方法
}

import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;

public class CryptoDemo {
    public static void main(String[] args) {
        // 生成秘密密钥
        byte[] keyBytes = "mySecretKey".getBytes();
        SecretKeySpec key = new SecretKeySpec(keyBytes, "AES");

        // 创建AES加密器
        Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
        cipher.init(Cipher.ENCRYPT_MODE, key);

        // 加密明文
        String plaintext = "Hello, world!";
        byte[] ciphertext = cipher.doFinal(plaintext.getBytes());

        // 解密密文
        cipher.init(Cipher.DECRYPT_MODE, key);
        String decryptedText = new String(cipher.doFinal(ciphertext));

        System.out.println("Encrypted text: " + ciphertext);
        System.out.println("Decrypted text: " + decryptedText);
    }
}

import java.util.regex.Pattern;

public class InputValidationDemo {
    public static void main(String[] args) {
        // 用于验证电子邮件地址的正则表达式
        Pattern emailPattern = Pattern.compile("^[a-zA-Z0-9_!#$%&'*+/=?`{|}~^.-]+@[a-zA-Z0-9.-]+$");

        // 验证用户输入的电子邮件地址
        String email = "john.doe@example.com";
        boolean isValidEmail = emailPattern.matcher(email).matches();

        if (isValidEmail) {
            System.out.println("Email address is valid.");
        } else {
            System.out.println("Email address is invalid.");
        }
    }
}