java rsa工具类

以下是一个简单的Java RSA工具类的示例代码：

import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import javax.crypto.Cipher;
import org.apache.commons.codec.binary.Base64;

public class RSAUtils {
    
    private static final String RSA_ALGORITHM = "RSA";
    
    public static KeyPair generateKeyPair() throws Exception {
        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance(RSA_ALGORITHM);
        keyPairGenerator.initialize(2048);
        return keyPairGenerator.genKeyPair();
    }
    
    public static String encrypt(String plainText, PublicKey publicKey) throws Exception {
        Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, publicKey);
        byte[] encryptedBytes = cipher.doFinal(plainText.getBytes());
        return Base64.encodeBase64String(encryptedBytes);
    }
    
    public static String decrypt(String encryptedText, PrivateKey privateKey) throws Exception {
        Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, privateKey);
        byte[] encryptedBytes = Base64.decodeBase64(encryptedText);
        byte[] decryptedBytes = cipher.doFinal(encryptedBytes);
        return new String(decryptedBytes);
    }
    
    public static PublicKey getPublicKey(byte[] publicKeyBytes) throws Exception {
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(publicKeyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(RSA_ALGORITHM);
        return keyFactory.generatePublic(keySpec);
    }
    
    public static PrivateKey getPrivateKey(byte[] privateKeyBytes) throws Exception {
        PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(privateKeyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(RSA_ALGORITHM);
        return keyFactory.generatePrivate(keySpec);
    }
}

使用示例：

public class Main {
    public static void main(String[] args) {
        try {
            // 生成密钥对
            KeyPair keyPair = RSAUtils.generateKeyPair();
            PublicKey publicKey = keyPair.getPublic();
            PrivateKey privateKey = keyPair.getPrivate();
            
            // 加密
            String plainText = "Hello, RSA!";
            String encryptedText = RSAUtils.encrypt(plainText, publicKey);
            System.out.println("Encrypted Text: " + encryptedText);
            
            // 解密
            String decryptedText = RSAUtils.decrypt(encryptedText, privateKey);
            System.out.println("Decrypted Text: " + decryptedText);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

请注意，这只是一个简单的示例，用于演示RSA加密和解密过程。在实际应用中，您需要更加严格的错误处理和安全性措施。