java使用RSA与AES加密解密的实例代码详解

首先了解下，什么是堆成加密，什么是非对称加密？

　　对称加密：加密与解密的密钥是相同的，加解密速度很快，比如AES

　　非对称加密：加密与解密的秘钥是不同的，速度较慢，比如RSA

•先看代码（先会用在研究）

　　相关依赖：

<dependency>
   <groupId>org.bouncycastle</groupId>
   <artifactId>bcprov-jdk15on</artifactId>
   <version>1.58</version>
 </dependency>

1，RSA工具类：

package cn.wangtao.utils;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.crypto.Cipher;
import java.io.ByteArrayOutputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
/**
 * @ClassName RSAUtils
 * @Auth 桃子
 * @Date 2019-6-25 15:15
 * @Version 1.0
 * @Description
 **/
public class RSAUtils {
  private static final String RSA = "RSA"; // 加密方式
  private static final Logger logger= LoggerFactory.getLogger(RSAUtils.class);
  //获取密钥
  public static KeyPair getKey() throws Exception {
    try {
      KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance(RSA, new BouncyCastleProvider());
      keyPairGenerator.initialize(2048); // 初始化密钥长度
      KeyPair keyPair = keyPairGenerator.generateKeyPair();// 生成密钥对
      return keyPair;
    } catch (Exception e) {
      logger.error("获取RSA秘钥对异常",e);
      throw new Exception("获取RSA秘钥对异常",e);
    }
  }
  //利用公钥进行加密
  public static String encryptStr(RSAPublicKey publicKey, String str) throws Exception {
    try {
      Cipher cipher = Cipher.getInstance(RSA, new BouncyCastleProvider());
      cipher.init(Cipher.ENCRYPT_MODE, publicKey);
      //加密
      byte[] bytes = getBytes(str.getBytes(), cipher);
      //2进行转换成16进制
      String result = CommonUtils.parseByte2HexStr(bytes);
      return result;
    } catch (Exception e) {
      logger.error("使用RSA公钥进行加密异常",e);
      throw new Exception("使用RSA公钥进行加密异常",e);
    }
  }
  //利用私钥进行解密
  public static String decryptStr(RSAPrivateKey privateKey, String str) throws Exception {
    try {
      Cipher cipher = Cipher.getInstance(RSA, new BouncyCastleProvider());
      cipher.init(Cipher.DECRYPT_MODE, privateKey); // 用密钥初始化此Cipher对象
      //16进制转换成2进制
      byte[] bytes = CommonUtils.parseHexStr2Byte(str);
      //解密
      byte[] bs = getBytes(bytes, cipher);
      String content=new String(bs,"utf-8");
      return content;
    } catch (Exception e) {
      logger.error("使用RSA私钥进行解密异常",e);
      throw new Exception("使用RSA私钥进行解密异常",e);
    }
  }
  //通过cipher获取字节数组
  public static byte[] getBytes(byte[] bytes,Cipher cipher) throws Exception {
    int blockSize = cipher.getBlockSize(); // 返回块的大小
    int j = 0;
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    while (bytes.length - j * blockSize > 0) { // 将二进制数据分块写入ByteArrayOutputStream中
      if(bytes.length-j*blockSize>blockSize){
        baos.write(cipher.doFinal(bytes, j * blockSize, blockSize));
      }else{
        baos.write(cipher.doFinal(bytes, j * blockSize,bytes.length-j*blockSize));
      }
      j++;
    }
    baos.close();
    byte[] byteArray = baos.toByteArray();
    return byteArray;
  }
  //保存秘钥对到文件
  public void saveRSAKey(String fileName) throws Exception {
    FileOutputStream fos=null;
    ObjectOutputStream oos=null;
    try {
      KeyPair keyPair = getKey();
      fos=new FileOutputStream(fileName);
      oos=new ObjectOutputStream(fos); //对象序列号
      oos.writeObject(keyPair);
    } catch (Exception e) {
      logger.error("RSA秘钥对保存到文件异常[{}]",fileName,e);
      throw new Exception("RSA秘钥对保存到文件异常",e);
    }finally {
      if(oos!=null){
        try {
          oos.close();
        } catch (IOException e1) {
          e1.printStackTrace();
        }
      }
      if(fos!=null){
        try {
          fos.close();
        } catch (IOException e1) {
          e1.printStackTrace();
        }
      }
    }
  }
}

　　2，CommonUtils通用工具类：

package cn.wangtao.utils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.IOException;
import java.io.Reader;
import java.io.Writer;
/**
 * @ClassName CommonUtils
 * @Auth 桃子
 * @Date 2019-6-27 12:51
 * @Version 1.0
 * @Description
 **/
public class CommonUtils {
  private static final Logger logger= LoggerFactory.getLogger(CommonUtils.class);
  //编码方式
  public static final String CODE_TYPE = "UTF-8";
  //字符补全
  private static final String[] consult = new String[]{"0","1","2","3","4","5","6","7","8","9","A","B","C","D","E","F","G"};
  //关流
  public static void closeReaderandWriter(Reader reader, Writer writer){
    if(writer!=null){
      try {
        writer.close();
      } catch (IOException e) {
        logger.error("关闭输出流失败",e);
      }
    }
    if(reader!=null){
      try {
        reader.close();
      } catch (IOException e) {
        logger.error("关闭输出流失败",e);
      }
    }
  }
  //将16进制转换为二进制
  public static byte[] parseHexStr2Byte(String hexStr) {
    if (hexStr.length() < 1)
      return null;
    byte[] result = new byte[hexStr.length()/2];
    for (int i = 0;i< hexStr.length()/2; i++) {
      int high = Integer.parseInt(hexStr.substring(i*2, i*2+1), 16);
      int low = Integer.parseInt(hexStr.substring(i*2+1, i*2+2), 16);
      result[i] = (byte) (high * 16 + low);
    }
    return result;
  }
  //将二进制转换成16进制
  public static String parseByte2HexStr(byte buf[]) {
    StringBuffer sb = new StringBuffer();
    for (int i = 0; i < buf.length; i++) {
      String hex = Integer.toHexString(buf[i] & 0xFF);
      if (hex.length() == 1) {
        hex = '0' + hex;
      }
      sb.append(hex.toUpperCase());
    }
    return sb.toString();
  }
  //补全字符
  public static String completionCodeFor16Bytes(String str) throws Exception {
    try{
      int num = str.getBytes(CODE_TYPE).length;
      int index = num%16;
      //进行加密内容补全操作, 加密内容应该为 16字节的倍数, 当不足16*n字节是进行补全, 差一位时 补全16+1位
      //补全字符 以 $ 开始,$后一位代表$后补全字符位数,之后全部以0进行补全;
      if(index != 0){
        StringBuffer sbBuffer = new StringBuffer(str);
        if(16-index == 1){
          sbBuffer.append("$" + consult[16-1] + addStr(16-1-1));
        }else{
          sbBuffer.append("$" + consult[16-index-1] + addStr(16-index-1-1));
        }
        str = sbBuffer.toString();
      }
      return str;
    }catch (Exception e){
      logger.error("使用AES加密前补全字符异常",e);
      throw new Exception("使用AES加密前补全字符异常",e);
    }
  }
  //追加字符
  public static String addStr(int num){
    StringBuffer sbBuffer = new StringBuffer("");
    for (int i = 0; i < num; i++) {
      sbBuffer.append("0");
    }
    return sbBuffer.toString();
  }
  //还原字符(进行字符判断)
  public static String resumeCodeOf16Bytes(String str) throws Exception{
    int indexOf = str.lastIndexOf("$");
    if(indexOf == -1){
      return str;
    }
    String trim = str.substring(indexOf+1,indexOf+2).trim();
    int num = 0;
    for (int i = 0; i < consult.length; i++) {
      if(trim.equals(consult[i])){
        num = i;
      }
    }
    if(num == 0){
      return str;
    }
    return str.substring(0,indexOf).trim();
  }
} 

　　3，AESUtils通用工具类：

package cn.wangtao.utils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import java.io.*;
import java.security.interfaces.RSAPrivateKey;
import java.util.Map;
/**
 * @ClassName AESUtils
 * @Auth 桃子
 * @Date 2019-6-27 12:05
 * @Version 1.0
 * @Description
 **/
public class AESUtils {
  private static final Logger logger= LoggerFactory.getLogger(AESUtils.class);
  //填充类型
  public static final String AES_TYPE = "AES/ECB/PKCS5Padding";
  private static final String AES = "AES"; // 加密方式
  public static final String DES_TYPE = "DES/ECB/PKCS5Padding";
  private static final String DES = "DES"; // 加密方式
  private final String defaultDesKey="11112222";//8位
  //对字符串加密
  public static String encryptStr(String content,String aesKey) throws Exception {
    try {
      SecretKeySpec key = new SecretKeySpec(aesKey.getBytes(),AES );
      Cipher cipher = Cipher.getInstance(AES_TYPE);
      cipher.init(Cipher.ENCRYPT_MODE, key);
      //字符补全
      String content16Str = CommonUtils.completionCodeFor16Bytes(content);
      byte[] encryptedData = cipher.doFinal(content16Str.getBytes(CommonUtils.CODE_TYPE));
      //2进制转换成16进制
      String hexStr = CommonUtils.parseByte2HexStr(encryptedData);
      return hexStr;
    } catch (Exception e) {
      logger.error("使用AES对字符串加密异常",e);
      throw new Exception("使用AES对字符串加密异常",e);
    }
  }
  //对字符串解密
  public static String decryptStr(String content,String aesKey) throws Exception {
    try {
      //16进制转换成2进制
      byte[] bytes = CommonUtils.parseHexStr2Byte(content);
      SecretKeySpec key = new SecretKeySpec(
          aesKey.getBytes(), AES);
      Cipher cipher = Cipher.getInstance(AES_TYPE);
      cipher.init(Cipher.DECRYPT_MODE, key);
      byte[] decryptedData = cipher.doFinal(bytes);
      String result=new String(decryptedData, CommonUtils.CODE_TYPE);
      //还原字符
      String orgResult = CommonUtils.resumeCodeOf16Bytes(result);
      return orgResult;
    } catch (Exception e) {
      logger.error("使用AES对字符串解密异常",e);
      throw new Exception("使用AES对字符串解密异常",e);
    }
  }
  //对文件加密
  public static File encryptFile(File orgFile, File encryptFile, Map<String,Object> context) throws Exception {
    logger.info("使用AES对文件加密开始，源文件地址[{}]加密后文件地址[{}]",orgFile.getPath(),encryptFile.getPath());
    BufferedReader br=null;
    BufferedWriter bw=null;
    try{
      //获取AESKEY ，如果没有为默认
      String aesKey = (String) context.get(Dirt.AES_KEY);
      br=new BufferedReader(new FileReader(orgFile));
      bw=(BufferedWriter)context.get(Dirt.BUFFEREDWRITER);
      if(null==bw){
        bw=new BufferedWriter(new FileWriter(encryptFile));
      }
      String len=null;
      while (null!=(len=br.readLine())){
        String encrypt= encryptStr(len,aesKey);
        bw.write(encrypt);
        bw.newLine();
        bw.flush();
      }
      logger.info("使用AES对文件加密结束，源文件地址[{}]加密后文件地址[{}]",orgFile.getPath(),encryptFile.getPath());
      return encryptFile;
    }catch (Exception e){
      logger.error("使用AES对文件加密异常,源文件地址[{}]加密后文件地址[{}]",orgFile.getPath(),encryptFile.getPath(),e);
      throw new Exception("使用AES对文件加密异常",e);
    }finally {
      CommonUtils.closeReaderandWriter(br,bw);
    }
  }
  //对文本解密，返回解密文件后的文件
  public static File decryptFile(File decryptfile, File encryptFile,Map<String,Object> context) throws Exception {
    logger.info("使用AES对文件解密开始，源加密文件地址[{}]解密后文件地址[{}]",encryptFile.getPath(),decryptfile.getPath());
    BufferedReader br=null;
    BufferedWriter bw=null;
    try{
      if(decryptfile.exists()){
        decryptfile.delete();
      }
      //边读边加密边写
      br=new BufferedReader(new FileReader(encryptFile));
      bw=new BufferedWriter(new FileWriter(decryptfile));
      String len=null;
      String aesKey=null;
      //判断是否加密
      RSAPrivateKey privateKey= (RSAPrivateKey) context.get(Dirt.RSAPRIVATEKEY);
      if(null!=privateKey){
        StringBuffer sb=new StringBuffer();
        while ((len=br.readLine())!=null){
          sb.append(len);
          if(len.equals("\n")||len.equals("")||len.equals("\r\n")||len.equals("\r")){
            aesKey=RSAUtils.decryptStr(privateKey,sb.toString());
            break;
          }
        }
      }
      if(null==aesKey){
        aesKey=(String) context.get(Dirt.AES_KEY);
      }
      logger.info("aesKey[{}]",aesKey);
      if(aesKey!=null){
        while ((len=br.readLine())!=null){
          String decrypt= decryptStr(len,aesKey);
          bw.write(decrypt);
          bw.flush();
          bw.newLine();
        }
      }
      logger.info("使用AES对文件解密结束，源加密文件地址[{}]解密后文件地址[{}]",encryptFile.getPath(),decryptfile.getPath());
      return decryptfile;
    }catch (Exception e){
      logger.error("使用AES对文件解密异常,源加密文件地址[{}]解密后文件地址[{}]",encryptFile.getPath(),decryptfile.getPath(),e);
      throw new Exception("使用AES对文件解密异常",e);
    }finally {
      CommonUtils.closeReaderandWriter(br,bw);
    }
  }
}

　　4，Dirt常量

package cn.wangtao.utils;
import java.security.interfaces.RSAPublicKey;
/**
 * @ClassName Dirt
 * @Auth 桃子
 * @Date 2019-6-27 14:20
 * @Version 1.0
 * @Description
 **/
public class Dirt {
  public static final String UPLOADFILEURL="uploadFileUrl";
  public static final String AES_KEY="aesKey";
  public static final String RSAPUBLICKEY="rsaPublicKey";
  public static final String RSAPRIVATEKEY="rsaPrivateKey";
  public final static String RETURNCODE="returnCode";
  public final static String RETURNMSG="returnMsg";
  public final static String FILENAME="fileName";
  public final static String ORGFILENAME="orgFileName";
  public final static String ENCRYPTFILE="encryptFile";
  public static final String BUFFEREDWRITER="bufferedWriter"; //是为了在原始文件中进行补充加密
  //返回码
  public final static String SUCCESSCODE="000000";
  public final static String FAILEDCODE="999999";
  //加密文件所放的目录
  public final static String BASELOCALDIR="XXX"; //基本目录路径
  public final static String ENCRYPTLOCALDIR="encrypt"; //加密文件目录

 总结

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