文件加密

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import java.io.File;
import java.io.FileReader;
import java.security.SecureRandom;

/**
 * 文件加密
 */
public class FileEncrypt {

    private static final String password = "9588028820109132570743325311898426347857298773549468758875018579537757772163084478873699447306034466200616411960574122434059469100235892702736860872901247123456";

    public static String encrypt(String filePath) throws Exception {
        StringBuilder builder = new StringBuilder();
        File file = new File(filePath);
        FileReader fileReader = new FileReader(file);
        int ch = -1;
        while( (ch=fileReader.read()) != -1 ){
            builder.append((char)ch);
        }
        fileReader.close();
        return HexUtils.toHex(FileEncrypt.encrypt(builder.toString().getBytes(), password));
    }

    public static String decrypt(String hexValue){
        return new String(FileEncrypt.decrypt(HexUtils.toBytes(hexValue), password));
    }

    /**
     * 加密
     *
     * @param datasource byte[]
     * @param password   String
     * @return byte[]
     */
    private static byte[] encrypt(byte[] datasource, String password) {
        try {
            SecureRandom random = new SecureRandom();
            DESKeySpec desKey = new DESKeySpec(password.getBytes());
//创建一个密匙工厂，然后用它把DESKeySpec转换成
            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
            SecretKey securekey = keyFactory.generateSecret(desKey);
//Cipher对象实际完成加密操作
            Cipher cipher = Cipher.getInstance("DES");
//用密匙初始化Cipher对象
            cipher.init(Cipher.ENCRYPT_MODE, securekey, random);
//现在，获取数据并加密
//正式执行加密操作
            return cipher.doFinal(datasource);
        } catch (Throwable e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 解密
     *
     * @param src      byte[]
     * @param password String
     * @return byte[]
     * @throws Exception
     */
    private static byte[] decrypt(byte[] src, String password){
        try {
            // DES算法要求有一个可信任的随机数源
            SecureRandom random = new SecureRandom();
// 创建一个DESKeySpec对象
            DESKeySpec desKey = new DESKeySpec(password.getBytes());
// 创建一个密匙工厂
            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
// 将DESKeySpec对象转换成SecretKey对象
            SecretKey securekey = keyFactory.generateSecret(desKey);
// Cipher对象实际完成解密操作
            Cipher cipher = Cipher.getInstance("DES");
// 用密匙初始化Cipher对象
            cipher.init(Cipher.DECRYPT_MODE, securekey, random);
// 真正开始解密操作
            return cipher.doFinal(src);
        }catch (Exception e){
            e.printStackTrace();
        }
        return null;
    }

}