这个版本绝对能用，本人亲测
注意：需要下载两个jar包
【commons-codec-1.11-bin.zip】下载地址如下：
/proper/commons-codec/download_codec.cgi
【commons-io-2.6-bin.zip】下载地址如下：
/proper/commons-io/download_io.cgi
java项目需要BuildPath进你的项目；
如果是web项目需要加入WEB-INF的lib目录中刷新即可。
源码如下：
import mons.codec.binary.Base64;import mons.io.IOUtils;import javax.crypto.Cipher;import java.io.ByteArrayOutputStream;import java.security.*;import java.security.interfaces.RSAPrivateKey;import java.security.interfaces.RSAPublicKey;import java.security.spec.InvalidKeySpecException;import java.security.spec.PKCS8EncodedKeySpec;import java.security.spec.X509EncodedKeySpec;import java.util.HashMap;import java.util.Map;public class RSAUtil {public static final String CHARSET = "UTF-8";public static final String RSA_ALGORITHM = "RSA";private static final String PUBLIC_KEY = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC/OpVr+aQu6B3stSUgsLcZWpaxatset8zTqat1FF543hoECcTnRqDXKwfX09J+RLCc/1fbITt0s4wUUwJNU7lKJSTGZp5/xHcEiFJjTa+XY6pQHQKvvZjAQMkyzC3H5tmaNTapKYJOAWw7u1dxcRNFdD3k5E+EiqSnlo30u7SLCwIDAQAB";private static final String PRIVATE_KEY = "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";public static void main (String[] args){try {// 如果你想使用不固定的秘钥可以打开下面三行// Map<String, String> keyMap = RSAUtil.createKeys(1024);// String publicKey = keyMap.get("publicKey");// String privateKey = keyMap.get("privateKey");System.out.println("公钥: \n\r" + PUBLIC_KEY);System.out.println("私钥： \n\r" + PRIVATE_KEY);System.out.println("公钥加密——私钥解密");String str = "站在大明门前守卫的禁卫军，事先没有接到\n" +"有关的命令，但看到大批盛装的官员来临，也就\n" +"以为确系举行大典，因而未加询问。进大明门即\n" +"为皇城。文武百官看到端门午门之前气氛平静，\n" +"城楼上下也无朝会的迹象，既无几案，站队点名\n" +"的御史和御前侍卫“大汉将军”也不见踪影，不免\n" +"心中揣测，互相询问：所谓午朝是否讹传？";System.out.println("\r明文：\r\n" + str);System.out.println("\r明文大小：\r\n" + str.getBytes().length);String encodedData = RSAUtil.privateEncrypt(str);System.out.println("密文：\r\n" + encodedData);String decodedData = RSAUtil.publicDecrypt(encodedData);System.out.println("解密后文字: \r\n" + decodedData);} catch (Exception e) {// TODO: handle exception}}public static Map<String, String> createKeys(int keySize){//为RSA算法创建一个KeyPairGenerator对象KeyPairGenerator kpg;try{kpg = KeyPairGenerator.getInstance(RSA_ALGORITHM);}catch(NoSuchAlgorithmException e){throw new IllegalArgumentException("No such algorithm-->[" + RSA_ALGORITHM + "]");}//初始化KeyPairGenerator对象,密钥长度kpg.initialize(keySize);//生成密匙对KeyPair keyPair = kpg.generateKeyPair();//得到公钥Key publicKey = keyPair.getPublic();String publicKeyStr = Base64.encodeBase64URLSafeString(publicKey.getEncoded());//得到私钥Key privateKey = keyPair.getPrivate();String privateKeyStr = Base64.encodeBase64URLSafeString(privateKey.getEncoded());Map<String, String> keyPairMap = new HashMap<String, String>();keyPairMap.put("publicKey", publicKeyStr);keyPairMap.put("privateKey", privateKeyStr);return keyPairMap;}/*** 得到公钥* @param publicKey 密钥字符串（经过base64编码）* @throws Exception*/public static RSAPublicKey getPublicKey(String publicKey) throws NoSuchAlgorithmException, InvalidKeySpecException {//通过X509编码的Key指令获得公钥对象KeyFactory keyFactory = KeyFactory.getInstance(RSA_ALGORITHM);X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(Base64.decodeBase64(publicKey));RSAPublicKey key = (RSAPublicKey) keyFactory.generatePublic(x509KeySpec);return key;}/*** 得到私钥* @param privateKey 密钥字符串（经过base64编码）* @throws Exception*/public static RSAPrivateKey getPrivateKey(String privateKey) throws NoSuchAlgorithmException, InvalidKeySpecException {//通过PKCS#8编码的Key指令获得私钥对象KeyFactory keyFactory = KeyFactory.getInstance(RSA_ALGORITHM);PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(Base64.decodeBase64(privateKey));RSAPrivateKey key = (RSAPrivateKey) keyFactory.generatePrivate(pkcs8KeySpec);return key;}/*** 公钥加密* @param data* @param publicKey* @return*/public static String publicEncrypt(String data){try{RSAPublicKey publicKey = RSAUtil.getPublicKey(PUBLIC_KEY);Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);cipher.init(Cipher.ENCRYPT_MODE, publicKey);return Base64.encodeBase64URLSafeString(rsaSplitCodec(cipher, Cipher.ENCRYPT_MODE, data.getBytes(CHARSET), publicKey.getModulus().bitLength()));}catch(Exception e){throw new RuntimeException("加密字符串[" + data + "]时遇到异常", e);}}/*** 私钥解密* @param data* @param privateKey* @return*/public static String privateDecrypt(String data){try{RSAPrivateKey privateKey = RSAUtil.getPrivateKey(PRIVATE_KEY);Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);cipher.init(Cipher.DECRYPT_MODE, privateKey);return new String(rsaSplitCodec(cipher, Cipher.DECRYPT_MODE, Base64.decodeBase64(data), privateKey.getModulus().bitLength()), CHARSET);}catch(Exception e){throw new RuntimeException("解密字符串[" + data + "]时遇到异常", e);}}/*** 私钥加密* @param data* @param privateKey* @return*/public static String privateEncrypt(String data){try{RSAPrivateKey privateKey = RSAUtil.getPrivateKey(PRIVATE_KEY);Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);cipher.init(Cipher.ENCRYPT_MODE, privateKey);return Base64.encodeBase64URLSafeString(rsaSplitCodec(cipher, Cipher.ENCRYPT_MODE, data.getBytes(CHARSET), privateKey.getModulus().bitLength()));}catch(Exception e){throw new RuntimeException("加密字符串[" + data + "]时遇到异常", e);}}/*** 公钥解密* @param data* @param publicKey* @return*/public static String publicDecrypt(String data){try{RSAPublicKey publicKey = RSAUtil.getPublicKey(PUBLIC_KEY);Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);cipher.init(Cipher.DECRYPT_MODE, publicKey);return new String(rsaSplitCodec(cipher, Cipher.DECRYPT_MODE, Base64.decodeBase64(data), publicKey.getModulus().bitLength()), CHARSET);}catch(Exception e){throw new RuntimeException("解密字符串[" + data + "]时遇到异常", e);}}private static byte[] rsaSplitCodec(Cipher cipher, int opmode, byte[] datas, int keySize){int maxBlock = 0;if(opmode == Cipher.DECRYPT_MODE){maxBlock = keySize / 8;}else{maxBlock = keySize / 8 - 11;}ByteArrayOutputStream out = new ByteArrayOutputStream();int offSet = 0;byte[] buff;int i = 0;try{while(datas.length > offSet){if(datas.length-offSet > maxBlock){buff = cipher.doFinal(datas, offSet, maxBlock);}else{buff = cipher.doFinal(datas, offSet, datas.length-offSet);}out.write(buff, 0, buff.length);i++;offSet = i * maxBlock;}}catch(Exception e){throw new RuntimeException("加解密阀值为["+maxBlock+"]的数据时发生异常", e);}byte[] resultDatas = out.toByteArray();IOUtils.closeQuietly(out);return resultDatas;}}
