Java DES 加解密字符串、文件 工具类通用

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.Key;
import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;
import javax.crypto.KeyGenerator;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

/**
* DES加解密工具类 单例工具类
*
* 1、通过指定密匙加密字符串、解密字符串
* 2、通过指定密匙加密文件、解密文件
*
* @author kaifang
*
*/
public class DESUtil {

/**
* 加密解密所需密匙
*/
private Key key;
/**
* des加解密工具类实例
*/
private static DESUtil desUtil;

/**
* 获取des工具类实例的方法
*
* @param key
* 加解密密匙
* @return des工具类实例
*/
public synchronized static DESUtil getInstance(String key) {
if (desUtil == null) {
desUtil = new DESUtil(key);
}
return desUtil;
}

/**
* des工具类私有构造
*
* @param str
*/
private DESUtil(String str) {
setKey(str); // 生成密匙
}

public Key getKey() {
return key;
}

public void setKey(Key key) {
this.key = key;
}

/**
* 根据参数生成 KEY
*/
private void setKey(String strKey) {
try {
KeyGenerator _generator = KeyGenerator.getInstance("DES");
_generator.init(new SecureRandom(strKey.getBytes()));
this.key = _generator.generateKey();
_generator = null;
} catch (Exception e) {
throw new RuntimeException(e);
}
}

/**
* 加密 String 明文输入 ,String 密文输出
*/
private String encryptStr(String strMing) {
byte[] byteMi = null;
byte[] byteMing = null;
String strMi = "";
BASE64Encoder base64en = new BASE64Encoder();
try {
byteMing = strMing.getBytes("UTF8");
byteMi = this.encryptByte(byteMing);
strMi = base64en.encode(byteMi);
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
base64en = null;
byteMing = null;
byteMi = null;
}
return strMi;
}

/**
* 解密 以 String 密文输入 ,String 明文输出
*
* @param strMi
* @return
*/
private String decryptStr(String strMi) {
BASE64Decoder base64De = new BASE64Decoder();
byte[] byteMing = null;
byte[] byteMi = null;
String strMing = "";
try {
byteMi = base64De.decodeBuffer(strMi);
byteMing = this.decryptByte(byteMi);
strMing = new String(byteMing, "UTF8");
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
base64De = null;
byteMing = null;
byteMi = null;
}
return strMing;
}

/**
* 加密以 byte[] 明文输入 ,byte[] 密文输出
*
* @param byteS
* @return
*/
private byte[] encryptByte(byte[] byteS) {
byte[] byteFina = null;
Cipher cipher;
try {
cipher = Cipher.getInstance("DES");
cipher.init(Cipher.ENCRYPT_MODE, key);
byteFina = cipher.doFinal(byteS);
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
cipher = null;
}
return byteFina;
}

/**
* 解密以 byte[] 密文输入 , 以 byte[] 明文输出
*
* @param byteD
* @return
*/
private byte[] decryptByte(byte[] byteD) {
Cipher cipher;
byte[] byteFina = null;
try {
cipher = Cipher.getInstance("DES");
cipher.init(Cipher.DECRYPT_MODE, key);
byteFina = cipher.doFinal(byteD);
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
cipher = null;
}
return byteFina;
}

/**
* 文件 file 进行加密并保存目标文件 destFile 中
*
* @param file
* 要加密的文件 如 c:/test/srcFile.txt
* @param destFile
* 加密后存放的文件名 如 c:/ 加密后文件 .txt
*/
private void encryptFile(File file, File destFile) {
InputStream is = null;
OutputStream out = null;
CipherInputStream cis = null;
try {
Cipher cipher = Cipher.getInstance("DES");
cipher.init(Cipher.ENCRYPT_MODE, this.key);
is = new FileInputStream(file);
out = new FileOutputStream(destFile);
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) {
throw new RuntimeException(e);
} finally {
try {
cis.close();
is.close();
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}

/**
* 文件采用 DES 算法解密文件
*
* @param file
* 已加密的文件 如 c:/ 加密后文件 .txt *
* @param destFile
* 解密后存放的文件名 如 c:/ test/ 解密后文件 .txt
*/
private void decryptFile(File file, File dest) {
InputStream is = null;
OutputStream out = null;
CipherOutputStream cos = null;
try {
Cipher cipher = Cipher.getInstance("DES");
cipher.init(Cipher.DECRYPT_MODE, this.key);
is = new FileInputStream(file);
out = new FileOutputStream(dest);
cos = new CipherOutputStream(out, cipher);
byte[] buffer = new byte[1024];
int r;
while ((r = is.read(buffer)) >= 0) {
cos.write(buffer, 0, r);
}
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
try {
cos.close();
out.close();
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}

/**
* des解密字符串的方法
*
* @param key
* 解密需要的密匙
* @param encrypt
* 密文
* @return 明文
*/
public static String getDecodeStr(String key, String encrypt) {
return DESUtil.getInstance(key).decryptStr(encrypt);
}

/**
* des加密字符串的方法
*
* @param key
* 加密所需密匙
* @param decrypt
* 明文
* @return 明文
*/
public static String getEncodeStr(String key, String decrypt) {
return DESUtil.getInstance(key).encryptStr(decrypt);
}

/**
* des解密文件
*
* @param key
* 解密所需密匙
* @param miFile
* 密文文件
* @param mingFile
* 明文文件
* @throws Exception
*/
public static void getDecodeFile(String key, File miFile, File mingFile) {
DESUtil.getInstance(key).decryptFile(miFile, mingFile);
}

/**
* des加密文件
*
* @param key
* 加密所需密匙
* @param mingFile
* 明文文件
* @param miFile
* 密文文件
* @throws Exception
*/
public static void getEncodeFile(String key, File mingFile, File miFile) {
DESUtil.getInstance(key).encryptFile(mingFile, miFile);
}

public static void main(String[] args) throws Exception {
/*
* DESUtil des = new DESUtil("kk"); // DES 加密文件 //
* des.encryptFile("G:/test.doc", "G:/ 加密 test.doc"); // DES 解密文件 //
* des.decryptFile("G:/ 加密 test.doc", "G:/ 解密 test.doc"); //String str1
* = "爱凯凯"; // DES 加密字符串 //String str2 = des.encryptStr(str1); // DES
* 解密字符串 String deStr = des.decryptStr("mm6DlWB9DJKxXeS5Xlh4TQ==");
*
* //System.out.println(" 加密前： " + str1); //System.out.println(" 加密后： "
* + str2); System.out.println(" 解密后： " + deStr);
*/

// System.out.println(DESUtil.getEncodeStr("kk", "爱凯凯"));
System.out.println(DESUtil.getDecodeStr("kk", "mm6DlWB9DJKxXeS5Xlh4TQ=="));
}
}

无需导入任何jar包哈，都是jdk自带的加密类。若是报错，请看：

http://blog.csdn.net/jbxiaozi/article/details/7351768

本文参考自：http://blog.csdn.net/shibenjie/article/details/5365355