使用java自带des加密算法实现文件加密和字符串加密

import java.io.bytearrayinputstream;
import java.io.bytearrayoutputstream;
import java.io.file;
import java.io.fileinputstream;
import java.io.fileoutputstream;
import java.io.inputstream;
import java.io.outputstream;
import java.security.securerandom;
import javax.crypto.cipher;
import javax.crypto.cipherinputstream;
import javax.crypto.secretkey;
import javax.crypto.secretkeyfactory;
import javax.crypto.spec.deskeyspec;
import javax.crypto.spec.ivparameterspec;
public class destool {
 private static final string passkey = "afasdf";
 private static final string deskey = "asfsdfsdf";
 /**
  * @comments ：对文件进行加密
  * @param filepath  要加密的文件路径
  * @param filename 文件
  * @param mode 加密模式  加密：cipher.encrypt_mode 解密：cipher.decrypt_mode
  * @return
  */
 public static string encoderordecoder(string filepath, string filename, int mode) {

  inputstream is = null;
  outputstream out = null;
  cipherinputstream cis = null;

  try {
   securerandom sr = new securerandom();
   deskeyspec dks = new deskeyspec(deskey.getbytes());
   secretkeyfactory keyfactory = secretkeyfactory.getinstance("des");
   secretkey securekey = keyfactory.generatesecret(dks);
   ivparameterspec iv = new ivparameterspec(passkey.getbytes());
   cipher cipher = cipher.getinstance("des/cbc/pkcs5padding");
   cipher.init(mode, securekey, iv, sr);

   file encoderfile = new file(filepath + file.separator + "encoder");
   if (!encoderfile.exists()) {
    encoderfile.mkdir();
   }

   is = new fileinputstream(filepath + file.separator + filename);
   out = new fileoutputstream(filepath + file.separator + "encoder"
     + file.separator + filename);

   cis = new cipherinputstream(is, cipher);
   byte[] buffer = new byte[1024];
   int r;
   while ((r = cis.read(buffer)) > 0) {
    out.write(buffer, 0, r);
   }

  } catch (exception e) {
   e.printstacktrace();
  } finally {
   try {
    if (is != null) {
     is.close();
    }
    if (cis != null) {
     cis.close();
    }
    if (out != null) {
     out.close();
    }
   } catch (exception e1){

   }
  }
  return filepath + file.separator + "encoder" + file.separator
    + filename;
 }

/**@comments ：对字符串进行加密
 * @param src 源字符串
 * @param mode 加密模式  加密：cipher.encrypt_mode 解密：cipher.decrypt_mode
 * @return
 */
public static string encoderordecoder( string src, int mode) {
  string tag="";
  inputstream is = null;
  outputstream out = null;
  cipherinputstream cis = null;

  try {
   securerandom sr = new securerandom();
   deskeyspec dks = new deskeyspec(deskey.getbytes());
   secretkeyfactory keyfactory = secretkeyfactory.getinstance("des");
   secretkey securekey = keyfactory.generatesecret(dks);
   ivparameterspec iv = new ivparameterspec(passkey.getbytes());
   cipher cipher = cipher.getinstance("des/cbc/pkcs5padding");
   cipher.init(mode, securekey, iv, sr);
   cis = new cipherinputstream(new bytearrayinputstream(src.getbytes()) , cipher);
   out=new bytearrayoutputstream();
   byte[] buffer = new byte[1024];
   int r;
   while ((r = cis.read(buffer)) > 0) {
    out.write(buffer, 0, r);
   }
   tag=out.tostring();
  } catch (exception e) {
   e.printstacktrace();
  } finally {
   try {
    if (is != null) {
     is.close();
    }
    if (cis != null) {
     cis.close();
    }
    if (out != null) {
     out.close();
    }
   } catch (exception e1){

   }
  }
  return tag;
 }
 public static void main(string[] args) {
  system.out.println("aaa"); 
  string t=encoderordecoder("aaa", cipher.encrypt_mode );
  system.out.println(t); 
  system.out.println(encoderordecoder(t, cipher.decrypt_mode ));
 }
}