java DES加密解密

package com.*;

import java.io.FileInputStream;
import java.io.FileOutputStream;
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;

public class DESUtil {

private Key key;

public DESUtil() {

}

public DESUtil(String str) {
setKey(str); // 生成密匙
}

public Key getKey() {
return key;
}

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

/**
* 依据參数生成 KEY
*/
public 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("Error initializing SqlMap class. Cause: " + e);
}
}

/**
* 加密 String 明文输入 ,String 密文输出
*/
public 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("Error initializing SqlMap class. Cause: " + 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
*/
public 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("Error initializing SqlMap class. Cause: " + 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("Error initializing SqlMap class. Cause: " + 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("Error initializing SqlMap class. Cause: " + 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称 如 c:/ 加密后文件 .txt
*/
public void encryptFile(String file, String destFile) throws Exception {
Cipher cipher = Cipher.getInstance("DES");
// cipher.init(Cipher.ENCRYPT_MODE, getKey());
cipher.init(Cipher.ENCRYPT_MODE, this.key);
InputStream is = new FileInputStream(file);
OutputStream out = new FileOutputStream(destFile);
CipherInputStream cis = new CipherInputStream(is, cipher);
byte[] buffer = new byte[1024];
int r;
while ((r = cis.read(buffer)) > 0) {
out.write(buffer, 0, r);
}
cis.close();
is.close();
out.close();
}

/**
* 文件採用 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称 如 c:/ test/ 解密后文件 .txt
*/
public void decryptFile(String file, String dest) throws Exception {
Cipher cipher = Cipher.getInstance("DES");
cipher.init(Cipher.DECRYPT_MODE, this.key);
InputStream is = new FileInputStream(file);
OutputStream out = new FileOutputStream(dest);
CipherOutputStream cos = new CipherOutputStream(out, cipher);
byte[] buffer = new byte[1024];
int r;
while ((r = is.read(buffer)) >= 0) {
cos.write(buffer, 0, r);
}
cos.close();
out.close();
is.close();
}

public static void main(String[] args) throws Exception {
DESUtil des = new DESUtil("fdsfsfsf");
// 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 = " 要加密的字符串 test";
// DES 加密字符串
String str2 = des.encryptStr(str1);
// DES 解密字符串
String deStr = des.decryptStr(str2);
System.out.println(" 加密前： " + str1);
System.out.println(" 加密后： " + str2);
System.out.println(" 解密后： " + deStr);
}
}