本文主要是介绍Java RSA非对称加密算法工具类，对大家解决编程问题具有一定的参考价值，需要的程序猿们随着小编来一起学习吧！

这里提供一个RSA加密算法的工具类，其中包含生成密钥、加密、解密、加签、验签等RSA常用的方法，可以直接使用

引入 Maven 依赖，(如果不引入则需要修改 base64加密、解密方法为 java.ultils.base64)

<dependency>
    <groupId>commons-codec</groupId>
    <artifactId>commons-codec</artifactId>
</dependency>
<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
</dependency>
<dependency>
    <groupId>com.auth0</groupId>
    <artifactId>java-jwt</artifactId>
    <version>3.19.2</version>
</dependency>
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
</dependency>

RSA工具类

package cn.lzscxb.common.utils;

import org.apache.commons.codec.binary.Base64;

import javax.crypto.Cipher;
import java.io.ByteArrayOutputStream;
import java.nio.charset.StandardCharsets;
import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;


/**
 * @Description RSA非对称加密算法工具类
 * @Author LzsCxb
 * @Date 2022/07/04 20:26
 */
public class RSAUtils {


    /**
     * RSA最大加密明文大小 2048/8-11
     */
    private static final int MAX_ENCRYPT_BLOCK = 245;

    /**
     * RSA最大解密密文大小 2048/8
     */
    private static final int MAX_DECRYPT_BLOCK = 256;
    /**
     * 定义加密方式
     */
    public static final String KEY_RSA = "RSA";
    /**
     * 定义公钥
     */
    public static final String KEY_RSA_PUBLICKEY = "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAhbMJG9i6O0T1hQ8oCoThMAg/0mlcerjYn+wMdZudoDCeEbxKYebs+WoNvBmV26A/co9yJ2+aUIf60kkJ6YwDh9pXSk2vgm7x0TAZ9HzRhpk6td4JO4HM9QpPaQG2Z3Tw8DnhNk7yGADp+weLqgULDDlUI7lm1s1G9OSY+ZK2TwjKPSC4j1CnjD6kvSW1qVGB0GhkreX877Rop+KbOmVE+JtQQgc+DcOgyMjGtSvDGrwBsI569wrywlOeFMLqVDlVLi3ugWDSEn3EHz63Nj442VSfR6ukxtifIwmogUI4VplXQoO4Am6kKH50tkggqVBNFGh0s5qavpig0XYkn42+6QIDAQAB";
    /**
     * 定义私钥
     */
    public static final String KEY_RSA_PRIVATEKEY = "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";
    /**
     * 定义签名算法
     */
    private final static String KEY_RSA_SIGNATURE = "sha256withRSA";

    /**
     * 生成公私密钥对
     */
    public static Map<String, Object> init() {
        Map<String, Object> map = null;
        try {
            KeyPairGenerator generator = KeyPairGenerator.getInstance(KEY_RSA);
            //设置密钥对的bit数，越大越安全，但速度减慢，一般使用512或1024、2048
            generator.initialize(2048);
            KeyPair keyPair = generator.generateKeyPair();
            // 获取公钥
            RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
            // 获取私钥
            RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
            // 将密钥对封装为Map
            map = new HashMap<String, Object>(2);
            map.put(KEY_RSA_PUBLICKEY, publicKey);
            map.put(KEY_RSA_PRIVATEKEY, privateKey);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }

        return map;
    }

    /**
     * 获取 RSAPublicKey
     */
    public static RSAPublicKey getPublicKey() throws Exception {
        byte[] decoded = Base64.decodeBase64(KEY_RSA_PUBLICKEY);
        KeyFactory factory = KeyFactory.getInstance(KEY_RSA);
        PublicKey publicKey = factory.generatePublic(new X509EncodedKeySpec(decoded));
        return (RSAPublicKey) publicKey;
    }

    /**
     * 获取 RSAPrivateKey
     */
    public static RSAPrivateKey getPrivateKey() throws Exception {
        byte[] decoded = Base64.decodeBase64(KEY_RSA_PRIVATEKEY);
        KeyFactory factory = KeyFactory.getInstance(KEY_RSA);
        PrivateKey privateKey = factory.generatePrivate(new PKCS8EncodedKeySpec(decoded));
        return (RSAPrivateKey) privateKey;
    }


    /**
     * 公钥加密  如果大于245则分段加密
     */
    public static String encryptByPublic(String encryptingStr, String publicKeyStr) {
        try {
            // 将公钥由字符串转为UTF-8格式的字节数组
            byte[] publicKeyBytes = Base64.decodeBase64(publicKeyStr);
            // 获得公钥
            X509EncodedKeySpec keySpec = new X509EncodedKeySpec(publicKeyBytes);
            // 取得待加密数据
            byte[] data = encryptingStr.getBytes(StandardCharsets.UTF_8);
            KeyFactory factory;
            factory = KeyFactory.getInstance(KEY_RSA);
            PublicKey publicKey = factory.generatePublic(keySpec);
            // 对数据加密
            Cipher cipher = Cipher.getInstance(factory.getAlgorithm());
            cipher.init(Cipher.ENCRYPT_MODE, publicKey);
            int inputLen = data.length;
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            int offSet = 0;
            byte[] cache;
            int i = 0;
            // 对数据分段加密
            while (inputLen - offSet > 0) {
                if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
                    cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
                } else {
                    cache = cipher.doFinal(data, offSet, inputLen - offSet);
                }
                out.write(cache, 0, cache.length);
                i++;
                offSet = i * MAX_ENCRYPT_BLOCK;
            }
            byte[] encryptedData = out.toByteArray();
            out.close();
            // 返回加密后由Base64编码的加密信息
            return new String(Base64.encodeBase64(encryptedData));
        } catch (Exception e) {
            e.printStackTrace();
        }

        return null;
    }

    /**
     * 私钥解密 如果大于256则分段解密
     */
    public static String decryptByPrivate(String encryptedStr, String privateKeyStr) {
        try {
            // 对私钥解密
            byte[] privateKeyBytes = Base64.decodeBase64(privateKeyStr);
            // 获得私钥
            PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(privateKeyBytes);
            // 获得待解密数据
            byte[] data = Base64.decodeBase64(encryptedStr);
            KeyFactory factory = KeyFactory.getInstance(KEY_RSA);
            PrivateKey privateKey = factory.generatePrivate(keySpec);
            // 对数据解密
            Cipher cipher = Cipher.getInstance(factory.getAlgorithm());
            cipher.init(Cipher.DECRYPT_MODE, privateKey);
            int inputLen = data.length;
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            int offSet = 0;
            byte[] cache;
            int i = 0;
            // 对数据分段解密
            while (inputLen - offSet > 0) {
                if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
                    cache = cipher.doFinal(data, offSet, MAX_DECRYPT_BLOCK);
                } else {
                    cache = cipher.doFinal(data, offSet, inputLen - offSet);
                }
                out.write(cache, 0, cache.length);
                i++;
                offSet = i * MAX_DECRYPT_BLOCK;
            }
            byte[] decryptedData = out.toByteArray();
            out.close();
            // 返回UTF-8编码的解密信息
            return new String(decryptedData, StandardCharsets.UTF_8);
        } catch (Exception e) {
            e.printStackTrace();
        }

        return null;
    }

    /**
     * 私钥加密  如果大于245则分段加密
     */
    public static String encryptByPrivate(String encryptingStr, String privateKeyStr) {
        try {
            byte[] privateKeyBytes = Base64.decodeBase64(privateKeyStr);
            // 获得私钥
            PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(privateKeyBytes);
            // 取得待加密数据
            byte[] data = encryptingStr.getBytes(StandardCharsets.UTF_8);
            KeyFactory factory = KeyFactory.getInstance(KEY_RSA);
            PrivateKey privateKey = factory.generatePrivate(keySpec);
            // 对数据加密
            Cipher cipher = Cipher.getInstance(factory.getAlgorithm());
            cipher.init(Cipher.ENCRYPT_MODE, privateKey);
            int inputLen = data.length;
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            int offSet = 0;
            byte[] cache;
            int i = 0;
            // 对数据分段加密
            while (inputLen - offSet > 0) {
                if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
                    cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
                } else {
                    cache = cipher.doFinal(data, offSet, inputLen - offSet);
                }
                out.write(cache, 0, cache.length);
                i++;
                offSet = i * MAX_ENCRYPT_BLOCK;
            }
            byte[] encryptedData = out.toByteArray();
            out.close();
            // 返回加密后由Base64编码的加密信息
            return new String(Base64.encodeBase64(encryptedData));
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 公钥解密 如果大于256则分段解密
     */
    public static String decryptByPublic(String encryptedStr, String publicKeyStr) {
        try {
            // 对公钥解密
            byte[] publicKeyBytes = Base64.decodeBase64(publicKeyStr);
            // 取得公钥
            X509EncodedKeySpec keySpec = new X509EncodedKeySpec(publicKeyBytes);
            // 取得待加密数据
            byte[] data = Base64.decodeBase64(encryptedStr);
            KeyFactory factory = KeyFactory.getInstance(KEY_RSA);
            PublicKey publicKey = factory.generatePublic(keySpec);
            // 对数据解密
            Cipher cipher = Cipher.getInstance(factory.getAlgorithm());
            cipher.init(Cipher.DECRYPT_MODE, publicKey);
            int inputLen = data.length;
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            int offSet = 0;
            byte[] cache;
            int i = 0;
            // 对数据分段解密
            while (inputLen - offSet > 0) {
                if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
                    cache = cipher.doFinal(data, offSet, MAX_DECRYPT_BLOCK);
                } else {
                    cache = cipher.doFinal(data, offSet, inputLen - offSet);
                }
                out.write(cache, 0, cache.length);
                i++;
                offSet = i * MAX_DECRYPT_BLOCK;
            }
            byte[] decryptedData = out.toByteArray();
            out.close();
            // 返回UTF-8编码的解密信息
            return new String(decryptedData, StandardCharsets.UTF_8);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 用私钥对加密数据进行签名
     */
    public static String sign(String encryptedStr, String privateKey) {
        String str = "";
        try {
            //将私钥加密数据字符串转换为字节数组
            byte[] data = encryptedStr.getBytes();
            // 解密由base64编码的私钥
            byte[] bytes = Base64.decodeBase64(privateKey);
            // 构造PKCS8EncodedKeySpec对象
            PKCS8EncodedKeySpec pkcs = new PKCS8EncodedKeySpec(bytes);
            // 指定的加密算法
            KeyFactory factory = KeyFactory.getInstance(KEY_RSA);
            // 取私钥对象
            PrivateKey key = factory.generatePrivate(pkcs);
            // 用私钥对信息生成数字签名
            Signature signature = Signature.getInstance(KEY_RSA_SIGNATURE);
            signature.initSign(key);
            signature.update(data);
            str = new String(Base64.encodeBase64(signature.sign()));
        } catch (Exception e) {
            e.printStackTrace();
        }
        return str;
    }

    /**
     * 校验数字签名
     *
     * @return 校验成功返回true，失败返回false
     */
    public static boolean verify(String encryptedStr, String publicKey, String sign) {
        boolean flag = false;
        try {
            //将私钥加密数据字符串转换为字节数组
            byte[] data = encryptedStr.getBytes();
            // 解密由base64编码的公钥
            byte[] bytes = Base64.decodeBase64(publicKey);
            // 构造X509EncodedKeySpec对象
            X509EncodedKeySpec keySpec = new X509EncodedKeySpec(bytes);
            // 指定的加密算法
            KeyFactory factory = KeyFactory.getInstance(KEY_RSA);
            // 取公钥对象
            PublicKey key = factory.generatePublic(keySpec);
            // 用公钥验证数字签名
            Signature signature = Signature.getInstance(KEY_RSA_SIGNATURE);
            signature.initVerify(key);
            signature.update(data);
            flag = signature.verify(Base64.decodeBase64(sign));
        } catch (Exception e) {
            e.printStackTrace();
        }
        return flag;
    }


    /**
     * 功能描述:格式化公私钥 C++格式
     * 公钥字符串开头要加上“-----BEGIN PUBLIC KEY-----\n”，结尾加上“\n-----END PUBLIC KEY-----\n”
     * 私钥字符串开头要加上“-----BEGIN RSA PRIVATE KEY-----\n”，结尾加上“\n-----END RSA PRIVATE KEY-----\n”
     *
     * @param str  要格式的字符串, flag
     * @param flag true为公 false为私
     * @return java.lang.String
     * @author xiaobu
     * @date 2020/3/18 16:40
     * @version 1.0
     */
    public static String formatStr(String str, boolean flag) {
        StringBuilder sb = new StringBuilder(str);
        for (int i = 0, len = sb.length(); i < len; i++) {
            if (i % 64 == 0) {
                sb.insert(i, "\n");
            }
        }
        if (flag) {
            sb = new StringBuilder("-----BEGIN PUBLIC KEY-----").append(sb).append("\n-----END PUBLIC KEY-----\n");
        } else {
            sb = new StringBuilder("-----BEGIN RSA PRIVATE KEY-----").append(sb).append("\n-----END RSA PRIVATE KEY-----\n");
        }
        return sb.toString();
    }


    /**
     * 测试方法
     */
    public static void main(String[] args) {
        // 生成 RSA 密钥
        Map<String, Object> map = new HashMap<String, Object>(2);
        map = RSAUtils.init();
        System.out.println(map);


        // 使用密钥进行认证
        String publicKey = RSAUtils.KEY_RSA_PUBLICKEY;
        String privateKey = RSAUtils.KEY_RSA_PRIVATEKEY;
        System.out.println("publicKey = " + publicKey);
        System.out.println("privateKey = " + privateKey);
        System.out.println("formatStr(publicKey,false) = " + formatStr(publicKey, true));
        System.out.println("formatStr(privateKey,false) = " + formatStr(privateKey, false));
        //由前四行代码获得公、私密钥
//        publicKey = "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAjVgHojy7oZ1Gl/iT9CXgvzlqPyV5wxvSRW7f6qDQh1FreYVTIbyVOees9LDbyFyocLCx6Cz3E4csHJvjwIem6SuZpIpmeJGS5bo04JVK2JwdqbFoIXd1Q5bGsA17nUNlnSR4h3ODM8OCKsC0Qpt1KSvN0WB2JUGBbUFwiPxrwEMLeYntz4cABBA/KYt5Ac9HBk5TDRDpFVlOM43t0B2219GxQOxm1x8fFjwzKV06nwYbmIuqoKqQVlym3FYrYiOdd0/iXXxp4Whi0Hdo7XyfaQhoCCd3FNnFP8Ng0HDAW99HxEaP9eIuC4wCV16o8jsUzm7V/yhTF1NlIPlTQW35hQIDAQAB";
        String str = "1 InnoDB 支持表锁和行锁，使用索引作为检索条件修改数据时采用行锁，否则采用表锁。\n" + "2 InnoDB 自动给修改操作加锁，给查询操作不自动加锁" + "3 行锁可能因为未使用索引而升级为表锁，所以除了检查索引是否创建的同时，也需要通过explain执行计划查询索引是否被实际使用。, RSA!";
        // 公钥加密，私钥解密
        String enStr1 = RSAUtils.encryptByPublic(str, publicKey);
        System.out.println("公钥加密后：" + enStr1);
        String deStr1 = RSAUtils.decryptByPrivate(enStr1, privateKey);
        System.out.println("私钥解密后：" + deStr1);
        // 私钥加密，公钥解密
        String enStr2 = RSAUtils.encryptByPrivate(str, privateKey);
        System.out.println("私钥加密后：" + enStr2);
        String deStr2 = RSAUtils.decryptByPublic(enStr2, publicKey);
        System.out.println("公钥解密后：" + deStr2);
        // 产生签名
        String sign = sign(enStr2, privateKey);
        System.out.println("签名:" + sign);
        // 验证签名
        boolean status = verify(enStr2, publicKey, sign);
        System.out.println("状态:" + status);
    }
}

JWT 工具类

package cn.lzscxb.common.utils;

import cn.lzscxb.entity.exception.ConditionException;
import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.exceptions.SignatureVerificationException;
import com.auth0.jwt.exceptions.TokenExpiredException;
import com.auth0.jwt.interfaces.Claim;
import com.auth0.jwt.interfaces.DecodedJWT;
import lombok.extern.slf4j.Slf4j;

import java.util.Calendar;
import java.util.Date;
import java.util.Map;

@Slf4j
public class TokenUtils {

    private static final String ISSUER = "lzscxb.cn";
    private static final Integer EXPIRE =30 ;

    /**
     * 生成token
     *
     * @param userId
     * @return
     * @throws Exception
     */
    public static String generateToken(Long userId, String phone, String avatar, String nickname) {
        Algorithm algorithm = null;
        try {
            algorithm = Algorithm.RSA256(RSAUtils.getPublicKey(), RSAUtils.getPrivateKey());
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
        Calendar calendar = Calendar.getInstance(); // 日历类用于生成过期时间
        calendar.setTime(new Date());
        calendar.add(Calendar.SECOND, EXPIRE);
        return JWT.create().withKeyId(String.valueOf(userId)).withIssuer(ISSUER).withExpiresAt(calendar.getTime()).withClaim("user_id", userId).withClaim("phone", phone).withClaim("avatar", avatar).withClaim("nickname", nickname).sign(algorithm);
    }

    public static Map<String, Claim> VerifyToken(String token) {
        try {
            Algorithm algorithm = Algorithm.RSA256(RSAUtils.getPublicKey(), RSAUtils.getPrivateKey());
            JWTVerifier verifier = JWT.require(algorithm).build();
            DecodedJWT jwt = verifier.verify(token);
            Map<String, Claim> claims = jwt.getClaims();
            return claims;
        } catch (TokenExpiredException e) {
            throw new ConditionException(401, "token 令牌已过期");
        } catch (SignatureVerificationException e) {
            e.printStackTrace();
            log.info(token);
            throw new ConditionException(401, "token 令牌无效");
        } catch (Exception e) {
            throw new RuntimeException(e);
        }

    }

}

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