DES加密解密（适用Windows和Linux系统）防止linux下解密失败

转自：http://blog.csdn.net/jerry_bj/article/details/8276552

package com.lasun.util;

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 sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

import com.lasun.core.services.ParameterManager;

public class DESUtil {
    Key key;

    public DESUtil() {

    }

    public DESUtil(String str) {
        setKey(str); // 生成密匙
    }

    public Key getKey() {
        return key;
    }

    public void setKey(Key key) {
        this.key = key;
    }

   <span style="color:#FF0000;"> /**
     * 根据参数生成 KEY
    */
    public void setKey (String strKey) {
        try {
            KeyGenerator _generator = KeyGenerator.getInstance("DES");
            //防止linux下 随机生成key
            SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG" );
            secureRandom.setSeed(strKey.getBytes());

            _generator.init(56,secureRandom);
            this.key = _generator.generateKey();
            _generator = null;
        } catch (Exception e) {
            throw new RuntimeException(
                    "Error initializing SqlMap class. Cause: " + e);
        }
    }</span>

    <span style="color:#3366FF;">/**
     * 根据参数生成 KEY
     */
    /*public void setKey(String strKey) {
        try {
            KeyGenerator _generator = KeyGenerator.getInstance("DES");
            _generator.init(new SecureRandom(strKey.getBytes()));
            this.key = _generator.generateKey();
            _generator = null;
        } catch (Exception e) {
            throw new RuntimeException(
                    "Error initializing SqlMap class. Cause: " + e);
        }
    }*/</span>

    /**
     * 加密 String 明文输入 ,String 密文输出
     */
    public String encryptStr(String strMing) {
        byte[] byteMi = null;
        byte[] byteMing = null;
        String strMi = "";
        BASE64Encoder base64en = new BASE64Encoder();
        try {
            byteMing = strMing.getBytes("UTF8");
            byteMi = this.encryptByte(byteMing);
            strMi = base64en.encode(byteMi);
        } catch (Exception e) {
            throw new RuntimeException(
                    "Error initializing SqlMap class. Cause: " + e);
        } finally {
            base64en = null;
            byteMing = null;
            byteMi = null;
        }
        return strMi;
    }

    /**
     * 解密 以 String 密文输入 ,String 明文输出
     *
     * @param strMi
     * @return
     */
    public String decryptStr(String strMi) {
        BASE64Decoder base64De = new BASE64Decoder();
        byte[] byteMing = null;
        byte[] byteMi = null;
        String strMing = "";
        try {
            byteMi = base64De.decodeBuffer(strMi);
            byteMing = this.decryptByte(byteMi);
            strMing = new String(byteMing, "UTF8");
        } catch (Exception e) {
            throw new RuntimeException(
                    "Error initializing SqlMap class. Cause: " + e);
        } finally {
            base64De = null;
            byteMing = null;
            byteMi = null;
        }
        return strMing;
    }

    /**
     * 加密以 byte[] 明文输入 ,byte[] 密文输出
     *
     * @param byteS
     * @return
     */
    private byte[] encryptByte(byte[] byteS) {
        byte[] byteFina = null;
        Cipher cipher;
        try {
            cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
            cipher.init(Cipher.ENCRYPT_MODE, key);
            byteFina = cipher.doFinal(byteS);
        } catch (Exception e) {
            throw new RuntimeException(
                    "Error initializing SqlMap class. Cause: " + e);
        } finally {
            cipher = null;
        }
        return byteFina;
    }

    /**
     * 解密以 byte[] 密文输入 , 以 byte[] 明文输出
     *
     * @param byteD
     * @return
     */
    private byte[] decryptByte(byte[] byteD) {
        Cipher cipher;
        byte[] byteFina = null;
        try {
            cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
            cipher.init(Cipher.DECRYPT_MODE, key);
            byteFina = cipher.doFinal(byteD);
        } catch (Exception e) {
            throw new RuntimeException(
                    "Error initializing SqlMap class. Cause: " + e);
        } finally {
            cipher = null;
        }
        return byteFina;
    }

    public static void main(String[] args) throws Exception {
        DESUtil des = new DESUtil("");
        // DES 加密文件
        // des.encryptFile("G:/test.doc", "G:/ 加密 test.doc");
        // DES 解密文件
        // des.decryptFile("G:/ 加密 test.doc", "G:/ 解密 test.doc");
        String str1 = "jui8qayuh7yhqwsh";
        // DES 加密字符串
        String str2 = des.encryptStr(str1);
        // DES 解密字符串
        String deStr = des.decryptStr(str2);
        System.out.println(" 加密前： " + str1);
        System.out.println(" 加密后： " + str2);
        System.out.println(" 加密后长度： " + str2.length());
        System.out.println(" 解密后： " + deStr);
    }
 }

说明：蓝色部分(注释掉的)代码 在windows下面好使，但是在linux下面会导致每次生成的key不一样、也就是说加密之后再解密就会保存，网上说由于两个操作系统处理补充字节默认补齐的方式不同,所以出现这样的情况；

红色部分代码防止在linux下随机生成key，在两个操作系统下通用。