content: package com.fit2cloud.common.utils;
  
  import lombok.SneakyThrows;
  import org.apache.commons.codec.binary.Base64;
  import org.apache.commons.collections4.KeyValue;
  import org.apache.commons.collections4.keyvalue.DefaultKeyValue;
  import org.apache.commons.lang3.StringUtils;
  
  import javax.crypto.Cipher;
  import java.io.File;
  import java.nio.charset.StandardCharsets;
  import java.nio.file.Files;
  import java.security.*;
  import java.security.interfaces.RSAPrivateKey;
  import java.security.interfaces.RSAPublicKey;
  import java.security.spec.PKCS8EncodedKeySpec;
  import java.security.spec.X509EncodedKeySpec;
  
  /**
   * @Company: FIT2CLOUD 飞致云
   * @Author: 张少虎
   * @Date: Created in 5:57 PM 2022/4/10
   * @Description: Please Write notes scientifically
   */
  public class RSAUtil {
  
      private static String RSA_KEY = null;
  
      private static String RUB_KEY = null;
  
  
      /**
       * 随机生成密钥对
       *
       * @throws NoSuchAlgorithmException
       */
      @SneakyThrows
      public static KeyValue<String, String> genKeyPair() {
          // KeyPairGenerator类用于生成公钥和私钥对，基于RSA算法生成对象
          KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");
          // 初始化密钥对生成器，密钥大小为96-1024位
          keyPairGen.initialize(2048, new SecureRandom());
          // 生成一个密钥对，保存在keyPair中
          KeyPair keyPair = keyPairGen.generateKeyPair();
          RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();   // 得到私钥
          RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();  // 得到公钥
          String publicKeyString = new String(Base64.encodeBase64(publicKey.getEncoded()));
          // 得到私钥字符串
          String privateKeyString = new String(Base64.encodeBase64((privateKey.getEncoded())));
          // key是表示公钥  value 私钥
          KeyValue<String, String> keyValue = new DefaultKeyValue<>(publicKeyString, privateKeyString);
          return keyValue;
      }
  
  
      /**
       * RSA公钥加密
       *
       * @param str       加密字符串
       * @param publicKey 公钥
       * @return 密文
       * @throws Exception 加密过程中的异常信息
       */
      @SneakyThrows
      public static String encrypt(String str, String publicKey) {
          //base64编码的公钥
          byte[] decoded = Base64.decodeBase64(publicKey);
          RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA").generatePublic(new X509EncodedKeySpec(decoded));
          //RSA加密
          Cipher cipher = Cipher.getInstance("RSA");
          cipher.init(Cipher.ENCRYPT_MODE, pubKey);
          String outStr = Base64.encodeBase64String(cipher.doFinal(str.getBytes(StandardCharsets.UTF_8)));
          return outStr;
      }
  
      /**
       * RSA私钥解密
       *
       * @param str        加密字符串
       * @param privateKey 私钥
       * @return 明文
       * @throws Exception 解密过程中的异常信息
       */
      @SneakyThrows
      public static String decrypt(String str, String privateKey) {
          //64位解码加密后的字符串
          byte[] inputByte = Base64.decodeBase64(str.getBytes(StandardCharsets.UTF_8));
          //base64编码的私钥
          byte[] decoded = Base64.decodeBase64(privateKey);
          RSAPrivateKey priKey = (RSAPrivateKey) KeyFactory.getInstance("RSA").generatePrivate(new PKCS8EncodedKeySpec(decoded));
          //RSA解密
          Cipher cipher = Cipher.getInstance("RSA");
          cipher.init(Cipher.DECRYPT_MODE, priKey);
          String outStr = new String(cipher.doFinal(inputByte));
          return outStr;
      }
  
      public static String getLocalRSA() {
          File file = new File("/opt/cloudexplorer/conf/RSA");
          if (file.exists()) {
              String text = FileUtils.txt2String(file);
              if (StringUtils.isNotBlank(text)) {
                  return text;
              }
          }
          throw new RuntimeException("RSA文件不存在");
      }
  
      @SneakyThrows
      public static void createLocalRSA(String text) {
          File file = new File("/opt/cloudexplorer/conf/RSA");
          if (file.exists()) {
              file.delete();
          }
          file.createNewFile();
          Files.write(file.toPath(), text.getBytes(StandardCharsets.UTF_8));
      }
  
      public static String getLocalPUB() {
          File file = new File("/opt/cloudexplorer/conf/RSA.PUB");
          if (file.exists()) {
              String text = FileUtils.txt2String(file);
              if (StringUtils.isNotBlank(text)) {
                  return text;
              }
          }
          throw new RuntimeException("RSA.PUB文件不存在");
      }
  
      @SneakyThrows
      public static void createLocalPUB(String text) {
          File file = new File("/opt/cloudexplorer/conf/RSA.PUB");
          if (file.exists()) {
              file.delete();
          }
          file.createNewFile();
          Files.write(file.toPath(), text.getBytes(StandardCharsets.UTF_8));
      }
  
      @SneakyThrows
      public static KeyValue<String, String> getKeyPair() {
          return getKeyPair(false);
      }
  
      @SneakyThrows
      public static KeyValue<String, String> getKeyPair(boolean createLocalFile) {
          if (StringUtils.isNotBlank(RSA_KEY) && StringUtils.isNotBlank(RUB_KEY)) {
              return new DefaultKeyValue<>(RUB_KEY, RSA_KEY);
          }
  
          String rsaStr = null, pubStr = null;
          try {
              rsaStr = getLocalRSA();
              pubStr = getLocalPUB();
          } catch (Exception e) {
              if (!createLocalFile) {
                  throw e;
              }
              KeyValue<String, String> keyPair = genKeyPair();
              pubStr = keyPair.getKey();
              rsaStr = keyPair.getValue();
  
              createLocalRSA(rsaStr);
              createLocalPUB(pubStr);
          }
  
          RSA_KEY = rsaStr;
          RUB_KEY = pubStr;
  
          return new DefaultKeyValue<>(pubStr, rsaStr);
      }
  
  }
  