algorithm identifier in public key not recognised: 1.2.156.10197.1.301如何解决

该错误通常表示Bouncy Castle库不支持该算法标识符。在这种情况下，您可以尝试更新Bouncy Castle库版本，或使用其他支持该算法的库。

如果您不想更改库，请检查公钥是否正确。如果公钥正确，则您可以尝试手动解析公钥并获取所需信息，而不是使用Bouncy Castle库中的默认方法。以下是一个示例代码，用于手动解析SM2公钥：

import java.io.BufferedReader;
import java.io.FileReader;
import java.math.BigInteger;
import java.security.Security;

import org.bouncycastle.asn1.ASN1Integer;
import org.bouncycastle.asn1.ASN1ObjectIdentifier;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.DERBitString;
import org.bouncycastle.asn1.DERSequence;
import org.bouncycastle.crypto.params.ECDomainParameters;
import org.bouncycastle.crypto.params.ECPublicKeyParameters;
import org.bouncycastle.jce.provider.BouncyCastleProvider;

public class SM2PublicKeyReader {

    public static void main(String[] args) throws Exception {
        // 添加Bouncy Castle提供程序
        Security.addProvider(new BouncyCastleProvider());

        // 读取PEM文件
        String pemFile = "sm2_public_key.pem";
        BufferedReader reader = new BufferedReader(new FileReader(pemFile));
        String line = null;
        StringBuilder sb = new StringBuilder();
        while ((line = reader.readLine()) != null) {
            if (line.startsWith("-----BEGIN PUBLIC KEY-----")) {
                continue;
            }
            if (line.startsWith("-----END PUBLIC KEY-----")) {
                break;
            }
            sb.append(line.trim());
        }
        byte[] derContent = java.util.Base64.getDecoder().decode(sb.toString());

        // 解析DER编码
        ASN1Sequence publicKeyInfo = ASN1Sequence.getInstance(derContent);
        ASN1Sequence algorithmIdentifier = ASN1Sequence.getInstance(publicKeyInfo.getObjectAt(0));
        ASN1ObjectIdentifier algorithm = ASN1ObjectIdentifier.getInstance(algorithmIdentifier.getObjectAt(0));
        ASN1Integer publicKeyX = ASN1Integer.getInstance(publicKeyInfo.getObjectAt(1));
        ASN1Integer publicKeyY = ASN1Integer.getInstance(publicKeyInfo.getObjectAt(2));

        // 获取公钥参数
        ECDomainParameters ecDomainParameters = ECDomainParameters.getByOID(algorithm);
        BigInteger x = publicKeyX.getValue();
        BigInteger y = publicKeyY.getValue();
        ECPublicKeyParameters ecPublicKeyParameters = new ECPublicKeyParameters(ecDomainParameters.getCurve().createPoint(x, y), ecDomainParameters);

        // 获取公钥
        byte[] publicKeyBytes = ecPublicKeyParameters.getQ().getEncoded(true);
        String publicKeyBase64 = java.util.Base64.getEncoder().encodeToString(publicKeyBytes);
        System.out.println("Public key in base64: " + publicKeyBase64);
    }

}

请注意，此代码仅适用于SM2公钥，并且假定PEM文件中只包含一个公钥。如果PEM文件中包含多个公钥或其他类型的密钥，则需要根据具体情况进行调整。