java 怎么从.p12文件中获取私钥并返回PrivateKey privateKey

你可以使用以下代码从.p12文件中获取私钥并返回PrivateKey对象：

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

public class KeyStoreExample {
    public static PrivateKey getPrivateKey(String p12FilePath, String password, String alias, String keyPassword) {
        try {
            // 加载.p12文件
            FileInputStream fis = new FileInputStream(p12FilePath);
            KeyStore keyStore = KeyStore.getInstance("PKCS12");
            keyStore.load(fis, password.toCharArray());

            // 获取私钥
            KeyStore.PasswordProtection keyPasswordProtection = new KeyStore.PasswordProtection(keyPassword.toCharArray());
            KeyStore.PrivateKeyEntry privateKeyEntry = (KeyStore.PrivateKeyEntry) keyStore.getEntry(alias, keyPasswordProtection);
            PrivateKey privateKey = privateKeyEntry.getPrivateKey();

            return privateKey;
        } catch (Exception e) {
            e.printStackTrace();
        }

        return null;
    }

    public static void main(String[] args) {
        String p12FilePath = "path/to/your/file.p12";
        String password = "password";
        String alias = "alias";
        String keyPassword = "keyPassword";

        PrivateKey privateKey = getPrivateKey(p12FilePath, password, alias, keyPassword);
        if (privateKey != null) {
            System.out.println("私钥: " + privateKey);
        }
    }
}

在上面的代码中，你需要将"path/to/your/file.p12"替换为你实际的.p12文件路径，"password"替换为.p12文件的密码，"alias"替换为私钥的别名，"keyPassword"替换为私钥的密码。运行代码后，你将会得到PrivateKey对象。