在android开发中或者java开发中,经常用一些加密或者解密文件的,下面是我最近测试的一个DES加密解密文件的方式,记录一下,防止以后忘记了!
下面直接贴代码把,详细的注释都写有:
package com.spring.des;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.SecretKeySpec;
/***
* Des文件加密解密
*
* @author spring sky<br>
* Email:[email protected]<br>
* QQ:840950105
*
*/
public class DesFileEncrypt {
/**
* 要加密的文件路径列表
*/
public static String[] filePath = { "D:/sasdfp.sql" };
/**
* 加密后的文件路径列表
*/
public static String[] outFilePath = new String[filePath.length];
private static final String KEY = "spring sky";
public DesFileEncrypt() {
super();
getKey(KEY);
initCipher();
//初始化开始加密文件
crateEncryptFile();
}
private Key key;
/***
* 解密密码
*/
private Cipher cipherDecrypt;
/**
* 加密密码
*/
private Cipher cipherEncrypt;
/**
* 加密文件平且记录加密后的文件路径
* */
private void crateEncryptFile() {
String outPath = null;
for (int i = 0; i < filePath.length; i++) {
try {
outPath = filePath[i].substring(0,filePath[i].lastIndexOf("."))+".bin";
encrypt(filePath[i], outPath);
outFilePath[i] = outPath;
System.out.println(filePath[i]+"加密完成,加密后的文件是:"+outFilePath[i]);
} catch (Exception e) {
e.printStackTrace();
}
}
System.out.println("=========================加密完成=======================");
}
/**
* 加密文件的核心
*
* @param file
* 要加密的文件
* @param destFile
* 加密后存放的文件名
*/
public void encrypt(String file, String destFile) throws Exception {
InputStream is = new FileInputStream(file);
OutputStream out = new FileOutputStream(destFile);
CipherInputStream cis = new CipherInputStream(is, cipherEncrypt);
byte[] buffer = new byte[1024];
int r;
while ((r = cis.read(buffer)) > 0) {
out.write(buffer, 0, r);
}
cis.close();
is.close();
out.close();
}
/***
* 解密文件
* @param destFile
*/
public void decrypt(String destFile) {
try {
InputStream is = new FileInputStream(destFile);
CipherInputStream cis = new CipherInputStream(is, cipherDecrypt);
BufferedReader reader = new BufferedReader(new InputStreamReader(
cis));
String line = null;
while ((line = reader.readLine()) != null) {
System.out.println(line);
}
reader.close();
cis.close();
is.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
private void initCipher() {
try {
// 加密的cipher
cipherEncrypt = Cipher.getInstance("DES");
cipherEncrypt.init(Cipher.ENCRYPT_MODE, this.key);
// 解密的cipher
cipherDecrypt = Cipher.getInstance("DES");
cipherDecrypt.init(Cipher.DECRYPT_MODE, this.key);
} catch (InvalidKeyException e) {
e.printStackTrace();
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
} catch (NoSuchPaddingException e) {
e.printStackTrace();
}
}
/**
* 自定义一个key
*
* @param string
*/
public Key getKey(String keyRule) {
// Key key = null;
byte[] keyByte = keyRule.getBytes();
// 创建一个空的八位数组,默认情况下为0
byte[] byteTemp = new byte[8];
// 将用户指定的规则转换成八位数组
for (int i = 0; i < byteTemp.length && i < keyByte.length; i++) {
byteTemp[i] = keyByte[i];
}
key = new SecretKeySpec(byteTemp, "DES");
return key;
}
/**
* 解密密码
*
* @return
*/
public Cipher getCipherEdcrypt() {
return cipherDecrypt;
}
/**
* 加密密码
*
* @return
*/
public Cipher getCipherEncrypt() {
return cipherEncrypt;
}
/***
* 测试加密解密
* @param args
*/
public static void main(String[] args) {
DesFileEncrypt desFileEncrypt = new DesFileEncrypt();
desFileEncrypt.decrypt(outFilePath[0]); //解密第一个文件平且测试解密后的结果
}
}