字符串转PrivateKey pcks1

可以使用Java的`KeyFactory`和`PKCS8EncodedKeySpec`类来将PKCS#1格式的私钥字符串转换成`PrivateKey`对象。但是，PKCS#1格式的私钥字符串通常是经过BASE64编码的，因此要先将其解码成字节数组，再进行转换。

下面是一个示例代码：

import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.util.Base64;

public class PKCS1ToPrivateKey {
    public static void main(String[] args) throws Exception {
        String pkcs1PrivateKeyStr = "-----BEGIN RSA PRIVATE KEY-----\n" +
                "MIICXQIBAAKBgQDnKNa7wEgVXoTjHj0jx4Pzq5wSdEoR0R6vOzr5g4VxQX6KpJ+t\n" +
                "yMwXGcJ4yQRc9z3fVZnJ+T8o8AVwGZ8gM1w7mZmZnJcRjYcqm+UxZtMq3iHjtmW\n" +
                "Aq1O5H3CfZ1/DfT8PHG8i2YhL2jYaS38NnT5oDQXjrr9vZZ5yX0+tJfG8QIDAQAB\n" +
                "AoGBAJvhnW1I0P6zJw+0N2WJz3MjZB0EzX7yM0Ou+5KgJ2+7z8S5nQ1U4tY6P4Hc\n" +
                "/hs2G6cpjYX0LdNQlq94qV4eS1nU9WtTbYnYxXJmZ/wg3dE4xVXjJpKQ3nAQCc3D\n" +
                "2GyGzN5KUO7tJpJXUZVXlIqOY1QzvSgPj2OzXa1wYJX4KmXNwWb6Lh0gPz8A3/Py\n" +
                "bT4N3tz6VlMw5KU8AkEA65K7gqZ0KoZk3Kt4xqzN0GX3QdCq3P9a5HlbFxl+7Jm\n" +
                "fP4Vv8xV2w5wRZ3lSPhDf0Z2ttoUOaYDxqBZUQp+cLjQJBAOQYdL7fLgVz7jQK2U\n" +
                "ZGpYzBpS7Rz2JXx2LQg/xB2LsZ8/r4aRTwU9A5K/64CQz0RQxhX2zvJxwzvtf7Rz\n" +
                "48PfEY0CQQC5EzZPo5NnM4vKj7w0O0ZpZ7WmYPaX+5jKo/9qEKEHVm1b5SUoVQ5U\n" +
                "aGc9YR1BqQeX4m4DXdFbT3mk6iB7bt4TAkB8gOQ1OghuK3VbqHt4Jg5J7/6tJ5pF\n" +
                "e8+oF5XqzZdGkc1T6U/6Cw6i+XtuK2zjL1mXcoU5lWbJ8v7PbVz5iMvZAkA+ylRf\n" +
                "C6p5NfE4Y/jXDY1h5NlI3q7WZm6y/41CgJ1OzP9Ni1CjSKyLgUQ3woG0wS7JG87c\n" +
                "4kYhY2REzLDM1JQJBAI7YX7x1vKvJyFw1JzgL0oIaZ4KK5k1Gd2WQqBmVZkT9Y9Y\n" +
                "g3s7N8x9me4g7zG1yTXJ+ZoFv4tqVlA9yF4=\n" +
                "-----END RSA PRIVATE KEY-----";

        // 去掉头尾部分，只保留私钥内容
        pkcs1PrivateKeyStr = pkcs1PrivateKeyStr.replace("-----BEGIN RSA PRIVATE KEY-----\n", "");
        pkcs1PrivateKeyStr = pkcs1PrivateKeyStr.replace("-----END RSA PRIVATE KEY-----", "");

        // 将BASE64编码的私钥字符串解码成字节数组
        byte[] pkcs1PrivateKeyBytes = Base64.getDecoder().decode(pkcs1PrivateKeyStr);

        // 将PKCS#1格式的私钥字节数组转换成PrivateKey对象
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(pkcs1PrivateKeyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        PrivateKey privateKey = keyFactory.generatePrivate(pkcs8KeySpec);

        // 输出PrivateKey对象
        System.out.println(privateKey);
    }
}

注意，上述代码中的私钥只用于示例，不要在实际应用中使用。