Java RSA加密文件解密错误加载并保存到文件

Question

我一直试图解决为什么我的代码片段做一些基本的加密工作不起作用。我已经测试了密钥生成器并直接使用加密和解密，这似乎工作正常。但是，如果我加载并保存到以下代码中的文件，它似乎在我的控制台中给我一个解密错误。我无法发现问题所在。我对密码学和Java相当陌生，因此非常感谢您的帮助！

import javax.crypto.Cipher;
import java.io.*;
import java.security.*;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;

import static java.nio.charset.StandardCharsets.UTF_8;

public class RSAwithDigitalMessage {
    public KeyPair generateKeyPair() throws Exception {
        KeyPairGenerator generator = KeyPairGenerator.getInstance("RSA");
        generator.initialize(2048, new SecureRandom());
        KeyPair pair = generator.generateKeyPair();

        return pair;
    }


    public String encrypt(String plainText, PublicKey publicKey) throws Exception {
        Cipher encryptCipher = Cipher.getInstance("RSA");
        encryptCipher.init(Cipher.ENCRYPT_MODE, publicKey);

        byte[] cipherText = encryptCipher.doFinal(plainText.getBytes(UTF_8));

        return Base64.getEncoder().encodeToString(cipherText);
    }

    public String decrypt(String cipherText, PrivateKey privateKey) throws Exception {
        byte[] bytes = Base64.getDecoder().decode(cipherText);

        Cipher decriptCipher = Cipher.getInstance("RSA");
        decriptCipher.init(Cipher.DECRYPT_MODE, privateKey);

        return new String(decriptCipher.doFinal(bytes), UTF_8);
    }

    private void dumpKeyPair(KeyPair keyPair) {
        PublicKey pub = keyPair.getPublic();
        System.out.println("Public Key: " + getHexString(pub.getEncoded()));

        PrivateKey priv = keyPair.getPrivate();
        System.out.println("Private Key: " + getHexString(priv.getEncoded()));
    }

    public String getHexString(byte[] b) {
        String result = "";
        for (int i = 0; i < b.length; i++) {
            result += Integer.toString((b[i] & 0xff) + 0x100, 16).substring(1);
        }
        return result;
    }

    public void SaveKeyPair(KeyPair keyPair, String username) throws IOException {
        PrivateKey privateKey = keyPair.getPrivate();
        PublicKey publicKey = keyPair.getPublic();
        String path = System.getProperty("user.dir");

        // Store Public Key.
        X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(
                publicKey.getEncoded());
        FileOutputStream fos = new FileOutputStream(path + "/"+username+"_public.key");
        fos.write(x509EncodedKeySpec.getEncoded());
        fos.close();

        // Store Private Key.
        PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(
                privateKey.getEncoded());
        fos = new FileOutputStream(path + "/"+username+"_private.key");
        fos.write(pkcs8EncodedKeySpec.getEncoded());
        fos.close();
    }

    public KeyPair LoadKeyPair(String username)
            throws IOException, NoSuchAlgorithmException,
            InvalidKeySpecException {
        // Read Public Key.
        String path = System.getProperty("user.dir");
        File filePublicKey = new File(path + "/"+username+"_public.key");
        FileInputStream fis = new FileInputStream(path + "/"+username+"_public.key");
        byte[] encodedPublicKey = new byte[(int) filePublicKey.length()];
        fis.read(encodedPublicKey);
        fis.close();

        // Read Private Key.
        File filePrivateKey = new File(path + "/private.key");
        fis = new FileInputStream(path + "/private.key");
        byte[] encodedPrivateKey = new byte[(int) filePrivateKey.length()];
        fis.read(encodedPrivateKey);
        fis.close();

        // Generate KeyPair.
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        X509EncodedKeySpec publicKeySpec = new X509EncodedKeySpec(
                encodedPublicKey);
        PublicKey publicKey = keyFactory.generatePublic(publicKeySpec);

        PKCS8EncodedKeySpec privateKeySpec = new PKCS8EncodedKeySpec(
                encodedPrivateKey);
        PrivateKey privateKey = keyFactory.generatePrivate(privateKeySpec);

        return new KeyPair(publicKey, privateKey);
    }

    public  String sign(String plainText, PrivateKey privateKey) throws Exception {
        Signature privateSignature = Signature.getInstance("SHA256withRSA");
        privateSignature.initSign(privateKey);
        privateSignature.update(plainText.getBytes(UTF_8));

        byte[] signature = privateSignature.sign();

        return Base64.getEncoder().encodeToString(signature);
    }

    public boolean verify(String plainText, String signature, PublicKey publicKey) throws Exception {
        Signature publicSignature = Signature.getInstance("SHA256withRSA");
        publicSignature.initVerify(publicKey);
        publicSignature.update(plainText.getBytes(UTF_8));

        byte[] signatureBytes = Base64.getDecoder().decode(signature);

        return publicSignature.verify(signatureBytes);
    }


}

更新：我已经删除了评论代码。在我的实际脚本中，我称之为：

RSAwithDigitalMessage RSAE = new RSAwithDigitalMessage();
KeyPair pair = RSAE.generateKeyPair();
String username = "Sdsdf";
RSAE.SaveKeyPair(pair, username);
KeyPair myKP = RSAE.LoadKeyPair(username);
string subject = "dfsf"
encSubject = RSAE.encrypt(subject, mykp.getPublic());
decSubject = RSAE.decrypt(encsubject,mykp.getPrivate());
console.log(decSubject)

这给我错误：Writer中的错误 - ＆gt;解密错误