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我在作业中感到困惑：D 给定一个 UML 图，我必须实现一个课程管理应用程序，其中一部分是 Student 类，如下所示

    public class Student extends Person implements Encryptable {
    private String program;
    private Vector<Course> courses;

//constructor. 
    public Student(String Name, String pnr, String tel, String prog) {
            super(Name, pnr, tel);
            program = prog;
            courses = new Vector<Course>();
        }
/* implementation of related methods 
  ......  */

        @Override
    public void encrypt(String password) {
    }

    @Override
    public void decrypt(String password) {  
    }

所有其他类以及该类的所有相关setter和getter也实现了Encryptable接口如下

public interface Encryptable {

    public void encrypt(String password);
    public void decrypt(String password);
}

在较早的任务中，我实现了一个类“PassworCrypter”，我应该使用该类

public class PasswordCrypter {
    Cipher ecipher;
    Cipher dcipher;
    SecretKey key;
    DESKeySpec dks;
    SecretKeyFactory skf;
    byte[] psword;

    public PasswordCrypter(String password) {

        try {
            psword = password.getBytes("UTF-16");
            dks = new DESKeySpec(psword);
            skf = SecretKeyFactory.getInstance("DES");
            key = skf.generateSecret(dks);
            ecipher = Cipher.getInstance("DES");
            ecipher.init(Cipher.ENCRYPT_MODE, key);
            dcipher = Cipher.getInstance("DES");
            dcipher.init(Cipher.DECRYPT_MODE, key);
        } catch (NoSuchAlgorithmException e) {
            throw new CrypterException(e);
        } catch (NoSuchPaddingException e) {
            throw new CrypterException(e);
        } catch (InvalidKeyException e) {
            throw new CrypterException(e);
        } catch (InvalidKeySpecException e) {
            throw new CrypterException(e);
        } catch (UnsupportedEncodingException e) {
            throw new CrypterException(e);
        }

    }

    public byte[] encrypt(byte[] array) {

        try {
            return ecipher.doFinal(array);
        } catch (IllegalBlockSizeException e) {
            throw new CrypterException(e);
        } catch (BadPaddingException e) {
            throw new CrypterException(e);
        }
    }

    public byte[] decrypt(byte[] array) {

        try {
            return dcipher.doFinal(array);
        } catch (IllegalBlockSizeException e) {
            throw new CrypterException(e);
        } catch (BadPaddingException e) {
            throw new CrypterException(e);
        }
    }
}

我应该在 Student 类的本地和继承字段上使用 PasswordCrypter 类。当学生对象被加密时，如果不先调用解密，就不可能获得学生姓名等数据。除非您需要访问其任何数据，否则应始终对 Student 对象进行加密。谁能给我想法或告诉我应该如何加密这个该死的学生:)

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1 回答 1

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我认为你有问题Encryptable。方法的签名应该是

public void encrypt(Encrypter enc);
public void decrypt(Decrypter dec);

您可以在其中定义两个单独的接口Encrypter和Decrypter. 所以最后你可以PasswordCrypter用作实现这两种方法的中心类。

 public class PasswordCrypter implements Encrypter,Decrypter  {

所以现在在你的学生班里你可以做

public void encrypt(Encrypter enc) {
   byte[] programbytes = enc.encrypt(program);
}

public void encrypt(Decrypter dec) {
   program = dec.decrypt(programbytes);
}
于 2012-10-20T14:08:15.253 回答