解决批量解密DES文件（以图片为例子）

1、我之前遇到一个问题，就是客户要求要解密存放在服务器上的多大10G的DES加密后的图片文件，而且这些图片分布在不同的文件下，而且我去上网找DES解密的小工具，但是都是只能对单一文件，所以我写一小段java程序去做，效果还行。
2、大概思路：获取所有要解密的文件名，之后对文件解密，然后删除掉源文件，之后把解密好的文件重命名为原文件名。
3、只要稍微修改也可以批量DES加密文件。
代码如下：

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.security.Key;

import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.spec.SecretKeySpec;

public class FileDES {
private Key mKey;
private Cipher mDecryptCipher;
private Cipher mEncryptCipher;
private static String key = “javadevelop”;
public FileDES(String key) throws Exception {
initKey(key);
initCipher();
}

private void initKey(String key) {    byte[] keyByte = key.getBytes();    byte[] byteTemp = new byte[8];    for (int i = 0; i < byteTemp.length && i < keyByte.length; i++) {        byteTemp[i] = keyByte[i];    }    mKey = new SecretKeySpec(byteTemp, "DES");}private void initCipher() throws Exception {    mEncryptCipher = Cipher.getInstance("DES");    mEncryptCipher.init(Cipher.ENCRYPT_MODE, mKey);    mDecryptCipher = Cipher.getInstance("DES");    mDecryptCipher.init(Cipher.DECRYPT_MODE, mKey);}

//加密文件方法实现
public void doEncryptFile(InputStream in, String savePath) {
if (in == null) {
System.out.println(“inputstream is null”);
return;
}
try {
CipherInputStream cin = new CipherInputStream(in, mEncryptCipher);
OutputStream os = new FileOutputStream(savePath);
byte[] bytes = new byte[1024];
int len = -1;
while ((len = cin.read(bytes)) > 0) {
os.write(bytes, 0, len);
os.flush();
}
os.close();
cin.close();
in.close();
System.out.println(“加密成功”);
} catch (Exception e) {
System.out.println(“加密失败”);
e.printStackTrace();
}
}

/** * 加密文件 *  * @param filePath *            需要加密的文件路径 * @param savePath *            加密后保存的位置 * @throws FileNotFoundException */public void doEncryptFile(String filePath, String savePath)        throws FileNotFoundException {    doEncryptFile(new FileInputStream(filePath), savePath);}/** * 解密文件 *  * @param filePath *            需要解密的文件路径 * @param savePath *            解密后保存的位置 * @throws FileNotFoundException */public void doDecryptFile(String filePath, String savePath)        throws FileNotFoundException {    doDecryptFile(new FileInputStream(filePath), savePath);}/** * 解密文件 *  * @param in */public void doDecryptFile(InputStream in, String savePath) {    if (in == null) {        System.out.println("inputstream is null");        return;    }    try {        CipherInputStream cin = new CipherInputStream(in, mDecryptCipher);        OutputStream os = new FileOutputStream(savePath);        byte[] bytes = new byte[1024];        int len = -1;        while ((len = cin.read(bytes)) > 0) {            os.write(bytes, 0, len);            os.flush();        }        os.close();        cin.close();        in.close();        System.out.println("解密成功");    } catch (Exception e) {        System.out.println("解密失败");        e.printStackTrace();    }}/** * 解密文件 *  * @param in */public void doDecryptFile(InputStream in) {    if (in == null) {        System.out.println("inputstream is null");        return;    }    try {        CipherInputStream cin = new CipherInputStream(in, mDecryptCipher);        BufferedReader reader = new BufferedReader(new InputStreamReader(                cin));        String line = null;        while ((line = reader.readLine()) != null) {            System.out.println(line);        }        reader.close();        cin.close();        in.close();        System.out.println("解密成功");    } catch (Exception e) {        System.out.println("解密失败");        e.printStackTrace();    }}

//获取文件夹下的所有文件名
private static void getFile(String path, String key) throws Exception {
File file = new File(path);
File[] array = file.listFiles();
for (int i = 0; i < array.length; i++) {
if (array[i].isFile()) {
handleFile(array[i], key);
} else if (array[i].isDirectory()) {
File[] fileList = array[i].listFiles();
for (int j = 0; j < fileList.length; j++) {
File readfile = fileList[j];
if (!readfile.isDirectory()) {
handleFile(readfile, key);
} else if (readfile.isDirectory()) {
getFile(readfile.getPath(), key);
}

            }        }    }}

//解密文件的方法集合
public static void handleFile(File file, String key) throws Exception {
FileDES fileDES = new FileDES(key);
String fileName = file.getName();
String newFileName = “gwsheng_” + fileName;
String filePath = file.getPath();
String newFilePath = null;
newFilePath = filePath.substring(0, filePath.lastIndexOf(“\”));
fileDES.doDecryptFile(filePath, newFilePath + “\” + newFileName);
deleteFile(filePath);
renameFile(newFilePath + “\” + newFileName, filePath);
}
//重命名文件名方法
private static void renameFile(String oldFileName, String newFileName) {
File oldFile = new File(oldFileName);
File newFile = new File(newFileName);
if (!oldFile.exists()) {
return;// 重命名文件不存在
}
if (newFile.exists())
System.out.println(“已经存在！”);
else {
oldFile.renameTo(newFile);
}

}

//删除原文件
private static void deleteFile(String path) {
// TODO Auto-generated method stub
File file = new File(path);
if (file.isFile() && file.exists()) {
file.delete();
}
}

/** * 解密文件 *  * @param filePath *            文件路径 * @throws Exception */public void doDecryptFile(String filePath) throws Exception {    doDecryptFile(new FileInputStream(filePath));}

//主方法
public static void main(String[] args) throws Exception {
getFile(“C:\Users\yt\Desktop\picture_for_prd”,key);
}
}