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程式碼下載

FileDES.java

import java.io.BufferedReader;
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 Cipher mEncryptCipher;

 public FileDES(String key) throws Exception {
  initKey(key);
  initCipher();
 }

 
 public void initKey(String keyRule) {
  byte[] keyByte = keyRule.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);
 }

 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("加密失敗");
   e.printStackTrace();
  }
 }

 public void doEncryptFile(String filePath, String savePath)
   throws FileNotFoundException {
  doEncryptFile(new FileInputStream(filePath), savePath);
 }

 public void doDecryptFile(InputStream in, String savePath) {
  if (in == null) {
   System.out.println("inputstream is null");
   return;
  }
  try {
   CipherInputStream cin = new CipherInputStream(in, mDecryptCipher);
   BufferedReader reader = new BufferedReader(new InputStreamReader(
     cin));
   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();
   }
   String line = null;
   while ((line = reader.readLine()) != null) {
    System.out.println(line);
   }
   os.close();
   reader.close();
   cin.close();
   in.close();
   System.out.println("解密成功");
  } catch (Exception e) {
   System.out.println("解密失敗");
   e.printStackTrace();
  }
 }

 
 public void doDecryptFile(String filePath, String savePath)
   throws Exception {
  doDecryptFile(new FileInputStream(filePath), savePath);
 }
}