java#文件上传附件的加密和解密工具类

package com.mk.workflow.common.util;

import org.springframework.util.Base64Utils;

import java.io.File;
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 javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import javax.servlet.ServletOutputStream;

/**
 * <p>
 * AES加密解密工具包
 * </p>
 */
public class AESUtils {

    private static final String ALGORITHM = "AES";
    private static final int KEY_SIZE = 128;
    private static final int CACHE_SIZE = 1024;

    /**
     * <p>
     * 生成随机密钥
     * </p>
     *
     * @return
     * @throws Exception
     */
    public static String getSecretKey() throws Exception {
        return getSecretKey(null);
    }

    /**
     * <p>
     * 生成密钥
     * </p>
     *
     * @param seed 密钥种子
     * @return
     * @throws Exception
     */
    public static String getSecretKey(String seed) throws Exception {
        KeyGenerator keyGenerator = KeyGenerator.getInstance(ALGORITHM);
        SecureRandom secureRandom;
        if (seed != null && !"".equals(seed)) {
            secureRandom = new SecureRandom(seed.getBytes());
        } else {
            secureRandom = new SecureRandom();
        }
        keyGenerator.init(KEY_SIZE, secureRandom);
        SecretKey secretKey = keyGenerator.generateKey();
        return Base64Utils.encodeToString(secretKey.getEncoded());
    }

    /**
     * <p>
     * 加密
     * </p>
     *
     * @param data
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] encrypt(byte[] data, String key) throws Exception {
        Key k = toKey(Base64Utils.decodeFromString(key));
        byte[] raw = k.getEncoded();
        SecretKeySpec secretKeySpec = new SecretKeySpec(raw, ALGORITHM);
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);
        return cipher.doFinal(data);
    }

    /**
     * <p>
     * 文件加密
     * </p>
     *
     * @param key
     * @param sourceFilePath
     * @param destFilePath
     * @throws Exception
     */
    public static void encryptFile(String key, String sourceFilePath, String destFilePath) throws Exception {
        File sourceFile = new File(sourceFilePath);
        File destFile = new File(destFilePath);
        if (sourceFile.exists() && sourceFile.isFile()) {
            if (!destFile.getParentFile().exists()) {
                destFile.getParentFile().mkdirs();
            }
            destFile.createNewFile();
            InputStream in = new FileInputStream(sourceFile);
            OutputStream out = new FileOutputStream(destFile);
            Key k = toKey(Base64Utils.decodeFromString(key));
            byte[] raw = k.getEncoded();
            SecretKeySpec secretKeySpec = new SecretKeySpec(raw, ALGORITHM);
            Cipher cipher = Cipher.getInstance(ALGORITHM);
            cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);
            CipherInputStream cin = new CipherInputStream(in, cipher);
            byte[] cache = new byte[CACHE_SIZE];
            int nRead = 0;
            while ((nRead = cin.read(cache)) != -1) {
                out.write(cache, 0, nRead);
                out.flush();
            }
            out.close();
            cin.close();
            in.close();
        }
    }


    /**
     * <p>
     * 文件加密
     * </p>
     *
     * @param key
     * @param fileInputStream
     * @param destFilePath
     * @throws Exception
     */
    public static void encryptFile(String key, InputStream fileInputStream, String destFilePath) throws Exception {

        if (fileInputStream == null) {
            return;
        }

        File destFile = new File(destFilePath);
        if (!destFile.getParentFile().exists()) {
            destFile.getParentFile().mkdirs();
        }
        destFile.createNewFile();

        InputStream in = fileInputStream;
        OutputStream out = new FileOutputStream(destFile);
        Key k = toKey(Base64Utils.decodeFromString(key));
        byte[] raw = k.getEncoded();
        SecretKeySpec secretKeySpec = new SecretKeySpec(raw, ALGORITHM);
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);
        CipherInputStream cin = new CipherInputStream(in, cipher);
        byte[] cache = new byte[CACHE_SIZE];
        int nRead = 0;
        while ((nRead = cin.read(cache)) != -1) {
            out.write(cache, 0, nRead);
            out.flush();
        }
        out.close();
        cin.close();
        in.close();

    }

    /**
     * <p>
     * 解密
     * </p>
     *
     * @param data
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] decrypt(byte[] data, String key) throws Exception {
        Key k = toKey(Base64Utils.decodeFromString(key));
        byte[] raw = k.getEncoded();
        SecretKeySpec secretKeySpec = new SecretKeySpec(raw, ALGORITHM);
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, secretKeySpec);
        return cipher.doFinal(data);
    }

    /**
     * <p>
     * 文件解密
     * </p>
     *
     * @param key
     * @param sourceFilePath
     * @param destFilePath
     * @throws Exception
     */
    public static void decryptFile(String key, String sourceFilePath, String destFilePath) throws Exception {
        File sourceFile = new File(sourceFilePath);
        File destFile = new File(destFilePath);
        if (sourceFile.exists() && sourceFile.isFile()) {
            if (!destFile.getParentFile().exists()) {
                destFile.getParentFile().mkdirs();
            }
            destFile.createNewFile();
            FileInputStream in = new FileInputStream(sourceFile);
            FileOutputStream out = new FileOutputStream(destFile);
            Key k = toKey(Base64Utils.decodeFromString(key));
            byte[] raw = k.getEncoded();
            SecretKeySpec secretKeySpec = new SecretKeySpec(raw, ALGORITHM);
            Cipher cipher = Cipher.getInstance(ALGORITHM);
            cipher.init(Cipher.DECRYPT_MODE, secretKeySpec);
            CipherOutputStream cout = new CipherOutputStream(out, cipher);
            byte[] cache = new byte[CACHE_SIZE];
            int nRead = 0;
            while ((nRead = in.read(cache)) != -1) {
                cout.write(cache, 0, nRead);
                cout.flush();
            }
            cout.close();
            out.close();
            in.close();
        }
    }

    /**
     * <p>
     * 文件解密
     * </p>
     *
     * @param key
     * @param sourceFilePath
     * @throws Exception
     */
    public static void decryptFile(String key, String sourceFilePath, ServletOutputStream outputStream) {
        File sourceFile = new File(sourceFilePath);
        if (sourceFile.exists() && sourceFile.isFile()) {
            FileInputStream in = null;
            CipherOutputStream cout = null;
            try {
                in = new FileInputStream(sourceFile);
                Key k = toKey(Base64Utils.decodeFromString(key));
                byte[] raw = k.getEncoded();
                SecretKeySpec secretKeySpec = new SecretKeySpec(raw, ALGORITHM);
                Cipher cipher = Cipher.getInstance(ALGORITHM);
                cipher.init(Cipher.DECRYPT_MODE, secretKeySpec);
                cout = new CipherOutputStream(outputStream, cipher);
                byte[] cache = new byte[CACHE_SIZE];
                int nRead = 0;
                while ((nRead = in.read(cache)) != -1) {
                    cout.write(cache, 0, nRead);
                    cout.flush();
                }
                cout.close();
                outputStream.close();
                in.close();

            } catch (Exception e) {
                e.printStackTrace();

            } finally {

                //文件流关闭

                if (cout != null) {
                    try {
                        cout.close();
                    } catch (Exception e) {

                    }

                }
                if (outputStream != null) {
                    try {
                        outputStream.close();
                    } catch (Exception e) {

                    }

                }

                if (in != null) {
                    try {
                        in.close();
                    } catch (Exception e) {

                    }

                }

            }

        }


    }

    /**
     * <p>
     * 转换密钥
     * </p>
     *
     * @param key
     * @return
     * @throws Exception
     */
    private static Key toKey(byte[] key) throws Exception {
        SecretKey secretKey = new SecretKeySpec(key, ALGORITHM);
        return secretKey;
    }

}