java读取sm2证书

Java可以通过Bouncy Castle库来读取SM2证书。以下是一个简单的示例：

import org.bouncycastle.asn1.ASN1Integer;
import org.bouncycastle.asn1.ASN1OctetString;
import org.bouncycastle.asn1.DERBitString;
import org.bouncycastle.asn1.DERSequence;
import org.bouncycastle.asn1.pkcs.PrivateKeyInfo;
import org.bouncycastle.asn1.x509.AlgorithmIdentifier;
import org.bouncycastle.asn1.x509.SubjectPublicKeyInfo;
import org.bouncycastle.crypto.params.ECPrivateKeyParameters;
import org.bouncycastle.crypto.params.ECPublicKeyParameters;
import org.bouncycastle.crypto.util.PrivateKeyInfoFactory;
import org.bouncycastle.crypto.util.SubjectPublicKeyInfoFactory;
import org.bouncycastle.crypto.util.PrivateKeyInfoFactory;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.util.encoders.Hex;

import java.io.FileInputStream;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.Provider;
import java.security.PublicKey;
import java.security.Security;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;
import java.security.spec.ECParameterSpec;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;

public class SM2CertReader {

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

        String certFilePath = "sm2-cert.crt";
        String privateKeyFilePath = "sm2-private-key.pem";

        // 读取证书
        FileInputStream certInputStream = new FileInputStream(certFilePath);
        X509Certificate cert = (X509Certificate) CertificateFactory.getInstance("X.509").generateCertificate(certInputStream);
        PublicKey publicKey = cert.getPublicKey();

        // 读取私钥
        FileInputStream privateKeyInputStream = new FileInputStream(privateKeyFilePath);
        byte[] privateKeyBytes = PEMReader.read(privateKeyInputStream);
        PKCS8EncodedKeySpec privateKeySpec = new PKCS8EncodedKeySpec(privateKeyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance("EC", BouncyCastleProvider.PROVIDER_NAME);
        PrivateKey privateKey = keyFactory.generatePrivate(privateKeySpec);

        // 打印公钥和私钥
        System.out.println("Public Key: " + Hex.toHexString(publicKey.getEncoded()));
        System.out.println("Private Key: " + Hex.toHexString(privateKey.getEncoded()));
    }

    private static class PEMReader {

        public static byte[] read(FileInputStream inputStream) throws Exception {
            byte[] data = new byte[inputStream.available()];
            inputStream.read(data);

            String str = new String(data);
            str = str.replaceAll("\\n", "")
                    .replace("-----BEGIN PRIVATE KEY-----", "")
                    .replace("-----END PRIVATE KEY-----", "");

            return org.bouncycastle.util.encoders.Base64.decode(str);
        }
    }

}

这个示例读取了一个SM2证书和私钥文件，然后打印出了公钥和私钥的HEX字符串。