java读取sm2证书

读取SM2证书需要使用Bouncy Castle等密码学库，以下是读取SM2证书的Java代码示例：

import java.io.FileInputStream;
import java.security.KeyStore;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.cert.Certificate;

import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.openssl.PEMReader;
import org.bouncycastle.util.io.pem.PemObject;
import org.bouncycastle.util.io.pem.PemReader;

public class SM2CertReader {
    public static void main(String[] args) throws Exception {
        Security.addProvider(new BouncyCastleProvider());

        // 读取证书
        FileInputStream fis = new FileInputStream("sm2cert.pfx");
        KeyStore ks = KeyStore.getInstance("PKCS12");
        ks.load(fis, "password".toCharArray());

        // 获取私钥
        PrivateKey privateKey = (PrivateKey) ks.getKey("alias", "password".toCharArray());

        // 获取证书链
        Certificate[] certs = (Certificate[]) ks.getCertificateChain("alias");

        // 获取公钥
        PublicKey publicKey = certs[0].getPublicKey();
        
        // 打印公钥和私钥
        System.out.println("public key: " + publicKey);
        System.out.println("private key: " + privateKey);
        
        // 读取PEM格式的证书
        FileInputStream pemFis = new FileInputStream("sm2cert.pem");
        PemReader pemReader = new PemReader(new InputStreamReader(pemFis));
        PemObject pemObject = pemReader.readPemObject();
        Certificate certificate = CertificateFactory.getInstance("X.509")
                .generateCertificate(new ByteArrayInputStream(pemObject.getContent()));
        PublicKey publicKey2 = certificate.getPublicKey();
        System.out.println("public key 2: " + publicKey2);
    }
}

其中，sm2cert.pfx是PKCS12格式的证书文件，sm2cert.pem是PEM格式的证书文件。使用PEM格式的证书文件需要使用PEMReader来解析。在以上代码中，私钥和证书链都是从PKCS12格式的证书文件中读取的。