sm2私钥base64转换 Java

下面是将SM2私钥进行Base64编码和解码的Java示例代码：

import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.util.encoders.Base64;

import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.Security;
import java.security.interfaces.ECPrivateKey;
import java.security.interfaces.ECPublicKey;

public class SM2PrivateKeyBase64 {
    public static void main(String[] args) throws Exception {
        Security.addProvider(new BouncyCastleProvider());

        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("EC", "BC");
        keyPairGenerator.initialize(256);
        KeyPair keyPair = keyPairGenerator.generateKeyPair();

        ECPrivateKey privateKey = (ECPrivateKey) keyPair.getPrivate();
        ECPublicKey publicKey = (ECPublicKey) keyPair.getPublic();

        // 将SM2私钥进行Base64编码
        byte[] privateKeyBytes = privateKey.getEncoded();
        String privateKeyBase64 = new String(Base64.encode(privateKeyBytes));
        System.out.println("SM2私钥Base64编码：" + privateKeyBase64);

        // 将Base64编码的SM2私钥进行解码
        byte[] privateKeyBytesDecoded = Base64.decode(privateKeyBase64);
        ECPrivateKey privateKeyDecoded = (ECPrivateKey) keyPairGenerator.generatePrivate(privateKeyBytesDecoded);
        System.out.println("解码后的SM2私钥：" + privateKeyDecoded);
    }
}

在上述代码中，我们使用BouncyCastle提供的SM2算法实现了一个简单的示例程序，该程序可以生成SM2的公私钥对，并将私钥进行Base64编码和解码。其中，私钥的Base64编码结果可以通过调用`new String(Base64.encode(privateKeyBytes))`方法实现，私钥的解码结果可以通过调用`Base64.decode(privateKeyBase64)`方法实现。