java 解密加密

import java.io.FileInputStream;   
import java.io.FileNotFoundException;   
import java.io.FileOutputStream;   
import java.io.IOException;   
import java.io.ObjectInputStream;   
import java.io.ObjectOutputStream;   
import java.security.Key;   
import java.security.MessageDigest;   
  
import javax.crypto.Cipher;   
import javax.crypto.KeyGenerator;   
  
public class Demo {   
    public static void main(String args[]) {   
        String password = "administrator";   
        try {   
            Demo.PrivEncrypt(password,"t.obj");   
        } catch (Exception e) {   
            e.printStackTrace();   
        }   
    }   
  
    /**  
     *   
     * @param oldStr  
     *            要加密的串  
     * @param keyFile  
     *            私有key所在的文件路径  
     * @throws Exception  
     */  
    public static void PrivEncrypt(String oldStr,String keyFile) throws Exception {   
        System.out.println("原始："+oldStr);   
        byte[] plainText = oldStr.getBytes("GBK");   
        Key key = getPriveKey(keyFile);   
        // 获得一个私鈅加密类Cipher，ECB是加密方式，PKCS5Padding是填充方法   
        Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");   
           
        cipher.init(Cipher.ENCRYPT_MODE, key);// 使用私鈅加密   
        byte[] cipherText = cipher.doFinal(plainText);   
        System.out.println("加密："+new String(cipherText, "UTF8"));   
           
        cipher.init(Cipher.DECRYPT_MODE, key);// 使用私钥解密   
        byte[] newPlainText = cipher.doFinal(cipherText);   
        System.out.println("解密："+new String(newPlainText, "UTF8"));   
    }   
  
    // 把Key 写到文件中：生成一个私有Key对象，保存在文件中   
    public static void setPriveKey(String file) {   
        FileOutputStream fos;   
        try {   
            fos = new FileOutputStream(file);   
            KeyGenerator keyGen = KeyGenerator.getInstance("DES");   
            keyGen.init(128);   
            Key key = keyGen.generateKey();// 生成私钥Key   
            ObjectOutputStream oos = new ObjectOutputStream(fos);   
            oos.writeObject(key);   
            oos.close();   
        } catch (Exception e1) {   
            e1.printStackTrace();   
        }   
    }   
    // 从文件中读Key：客户端可以根据管理员提供的私钥Key文件提取Key对象   
    public static Key getPriveKey(String file) throws Exception {   
        FileInputStream fis = new FileInputStream(file);   
        ObjectInputStream ois = new ObjectInputStream(fis);   
        Key key = (Key) ois.readObject();   
        return key;   
    }   
}   
/* 运行结果：  
 * 原始：administrator   
 * 加密：!Y????I?? ??R;?  
 * 解密：administrator  
 */