字符串解密加密

调用如下：

Des3.encode(String str);//对字符串str加密
Des3.decode(String str);//对字符串str解密

Des3.java

import java.security.Key;

import javax.crypto.Cipher;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESedeKeySpec;
import javax.crypto.spec.IvParameterSpec;

/**
 * 3DES加密工具类
 */
public class Des3 {
    // **
    private static String secretKey = "123123123123";//自定义
    // 向量
    private final static String iv = "123";//自定义
    // 加解密统一使用的编码方式
    private final static String encoding = "utf-8";

    static Des3 des3;

    private Des3() {
    }

    public static Des3 getDes3() {
    if (null == des3) {
        des3 = new Des3();
    }
    return des3;
    }

    public void setDecryptKey(String key) {
        this.secretKey = key;
    }

    /**
     * 3DES加密
     * 
     * @param plainText
     *            普通文本
     * @return
     * @throws Exception
     */
    public static String encode(String plainText) {
        Key deskey = null;
        DESedeKeySpec spec = null;
        SecretKeyFactory keyfactory = null;
        Cipher cipher = null;
        byte[] encryptData = null;
        try {
            spec = new DESedeKeySpec(secretKey.getBytes());
            keyfactory = SecretKeyFactory.getInstance("desede");
            deskey = keyfactory.generateSecret(spec);
            cipher = Cipher.getInstance("desede/CBC/PKCS5Padding");
            IvParameterSpec ips = new IvParameterSpec(iv.getBytes());
            cipher.init(Cipher.ENCRYPT_MODE, deskey, ips);
            encryptData = cipher.doFinal(plainText.getBytes(encoding));
        } catch (Exception e) {
            e.printStackTrace();
        }
        return Base64.encode(encryptData);
    }

    /**
     * 3DES解密
     * 
     * @param encryptText
     *            加密文本
     * @return
     */
    public static String decode(String encryptText) throws Exception {
        Key deskey = null;
        DESedeKeySpec spec = null;
        SecretKeyFactory keyfactory;
        Cipher cipher = null;
        byte[] decryptData = null;
        spec = new DESedeKeySpec(secretKey.getBytes());
        keyfactory = SecretKeyFactory.getInstance("desede");
        deskey = keyfactory.generateSecret(spec);
        cipher = Cipher.getInstance("desede/CBC/PKCS5Padding");
        IvParameterSpec ips = new IvParameterSpec(iv.getBytes());
        cipher.init(Cipher.DECRYPT_MODE, deskey, ips);
        decryptData = cipher.doFinal(Base64.decode(encryptText));
        return new String(decryptData, encoding);
    }
}

Base64.java

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;

/**
 * Base64编码工具类
 */
public class Base64 {
    private static final char[] legalChars =                  "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".toCharArray();

    public static String encode(byte[] data) {
        int start = 0;
        int len = data.length;
        StringBuffer buf = new StringBuffer(data.length * 3 / 2);

        int end = len - 3;
        int i = start;
        int n = 0;

        while (i <= end) {
            int d = ((((int) data[i]) & 0x0ff) << 16) | ((((int) data[i + 1]) & 0x0ff)                    
                    << 8) | (((int) data[i + 2]) & 0x0ff);

            buf.append(legalChars[(d >> 18) & 63]);
            buf.append(legalChars[(d >> 12) & 63]);
            buf.append(legalChars[(d >> 6) & 63]);
            buf.append(legalChars[d & 63]);

            i += 3;

            if (n++ >= 14) {
            n = 0;
            buf.append(" ");
            }
        }

        if (i == start + len - 2) {
            int d = ((((int) data[i]) & 0x0ff) << 16) | ((((int) data[i + 1]) & 255) << 8);

            buf.append(legalChars[(d >> 18) & 63]);
            buf.append(legalChars[(d >> 12) & 63]);
            buf.append(legalChars[(d >> 6) & 63]);
            buf.append("=");
        } else if (i == start + len - 1) {
            int d = (((int) data[i]) & 0x0ff) << 16;

            buf.append(legalChars[(d >> 18) & 63]);
            buf.append(legalChars[(d >> 12) & 63]);
            buf.append("==");
        }

        return buf.toString();
    }

    private static int decode(char c) {
        if (c >= 'A' && c <= 'Z')
            return ((int) c) - 65;
        else if (c >= 'a' && c <= 'z')
            return ((int) c) - 97 + 26;
        else if (c >= '0' && c <= '9')
            return ((int) c) - 48 + 26 + 26;
        else
            switch (c) {
            case '+':
            return 62;
            case '/':
            return 63;
            case '=':
            return 0;
            default:
            throw new RuntimeException("unexpected code: " + c);
        }
    }

    /**
     * Decodes the given Base64 encoded String to a new byte array. The byte
     * array holding the decoded data is returned.
     */

    public static byte[] decode(String s) {

        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        try {
            decode(s, bos);
        } catch (IOException e) {
            throw new RuntimeException();
        }
        byte[] decodedBytes = bos.toByteArray();
        try {
            bos.close();
            bos = null;
        } catch (IOException ex) {
            System.err.println("Error while decoding BASE64: " + ex.toString());
        }
        return decodedBytes;
    }

    private static void decode(String s, OutputStream os) throws IOException {
        int i = 0;

        int len = s.length();

        while (true) {
            while (i < len && s.charAt(i) <= ' ')
            i++;

            if (i == len)
            break;

            int tri = (decode(s.charAt(i)) << 18) + (decode(s.charAt(i + 1)) << 12) + 
                      (decode(s.charAt(i + 2)) << 6) + (decode(s.charAt(i + 3)));

            os.write((tri >> 16) & 255);
            if (s.charAt(i + 2) == '=')
            break;
            os.write((tri >> 8) & 255);
            if (s.charAt(i + 3) == '=')
            break;
            os.write(tri & 255);

            i += 4;
        }
    }
}