java 写一个SM4加密解密代码

以下是 Java 实现的 SM4 加密解密的代码：

import java.security.SecureRandom;
import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import org.apache.commons.codec.binary.Base64;

public class SM4Utils {
    private String secretKey = ""; // 密钥
    private String iv = ""; // 向量
    private boolean hexString = false;

    public SM4Utils() {
    }

    public SM4Utils(String secretKey) {
        this.secretKey = secretKey;
        this.iv = secretKey.substring(0, 16);
    }

    public SM4Utils(String secretKey, String iv) {
        this.secretKey = secretKey;
        this.iv = iv;
    }

    public void setHexString(boolean hexString) {
        this.hexString = hexString;
    }

    public String encryptData_ECB(String plainText) throws Exception {
        byte[] keyBytes = hexString ? Base64.decodeBase64(secretKey) : secretKey.getBytes("UTF-8");
        byte[] plainBytes = hexString ? Base64.decodeBase64(plainText) : plainText.getBytes("UTF-8");
        Cipher cipher = Cipher.getInstance("SM4/ECB/PKCS5Padding");
        cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(keyBytes, "SM4"));
        byte[] encryptedBytes = cipher.doFinal(plainBytes);
        return hexString ? Base64.encodeBase64String(encryptedBytes) : new String(encryptedBytes, "UTF-8");
    }

    public String decryptData_ECB(String cipherText) throws Exception {
        byte[] keyBytes = hexString ? Base64.decodeBase64(secretKey) : secretKey.getBytes("UTF-8");
        byte[] encryptedBytes = hexString ? Base64.decodeBase64(cipherText) : cipherText.getBytes("UTF-8");
        Cipher cipher = Cipher.getInstance("SM4/ECB/PKCS5Padding");
        cipher.init(Cipher.DECRYPT_MODE, new SecretKeySpec(keyBytes, "SM4"));
        byte[] decryptedBytes = cipher.doFinal(encryptedBytes);
        return hexString ? Base64.encodeBase64String(decryptedBytes) : new String(decryptedBytes, "UTF-8");
    }

    public String encryptData_CBC(String plainText) throws Exception {
        byte[] keyBytes = hexString ? Base64.decodeBase64(secretKey) : secretKey.getBytes("UTF-8");
        byte[] plainBytes = hexString ? Base64.decodeBase64(plainText) : plainText.getBytes("UTF-8");
        byte[] ivBytes = hexString ? Base64.decodeBase64(iv) : iv.getBytes("UTF-8");
        Cipher cipher = Cipher.getInstance("SM4/CBC/PKCS5Padding");
        cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(keyBytes, "SM4"), new IvParameterSpec(ivBytes));
        byte[] encryptedBytes = cipher.doFinal(plainBytes);
        return hexString ? Base64.encodeBase64String(encryptedBytes) : new String(encryptedBytes, "UTF-8");
    }

    public String decryptData_CBC(String cipherText) throws Exception {
        byte[] keyBytes = hexString ? Base64.decodeBase64(secretKey) : secretKey.getBytes("UTF-8");
        byte[] encryptedBytes = hexString ? Base64.decodeBase64(cipherText) : cipherText.getBytes("UTF-8");
        byte[] ivBytes = hexString ? Base64.decodeBase64(iv) : iv.getBytes("UTF-8");
        Cipher cipher = Cipher.getInstance("SM4/CBC/PKCS5Padding");
        cipher.init(Cipher.DECRYPT_MODE, new SecretKeySpec(keyBytes, "SM4"), new IvParameterSpec(ivBytes));
        byte[] decryptedBytes = cipher.doFinal(encryptedBytes);
        return hexString ? Base64.encodeBase64String(decryptedBytes) : new String(decryptedBytes, "UTF-8");
    }

    public static void main(String[] args) throws Exception {
        SM4Utils sm4 = new SM4Utils("1234567890123456");
        String plainText = "Hello, world!";
        String cipherText = sm4.encryptData_CBC(plainText);
        String decryptedText = sm4.decryptData_CBC(cipherText);
        System.out.println("Plain Text: " + plainText);
        System.out.println("Cipher Text: " + cipherText);
        System.out.println("Decrypted Text: " + decryptedText);
    }
}

其中，`SM4Utils` 类包含了 ECB 和 CBC 两种模式的加密解密方法，可以根据需要选择。在主函数中，演示了如何使用 `SM4Utils` 类进行加密解密。注意，这里使用的是 Apache Commons Codec 库来进行 Base64 编解码。