在JAVA开发环境中如何对文件和数据进行有效的加密，特别是里面API的调用

DES 加解密的封装和 使用的例子（转） -------------------------------------------------------------------------------- DES加密封装 package org.jtool.desutils; import java.security.SecureRandom; import javax.crypto.*; import javax.crypto.spec.DESKeySpec; public class DESEncrypt { private byte[] desKey; public DESEncrypt(byte[] desKey) { this.desKey = desKey; } public byte[] doEncrypt(byte[] plainText) throws Exception { // DES算法要求有一个可信任的随机数源 SecureRandom sr = new SecureRandom(); byte rawKeyData[] = desKey;/* 用某种方法获得密匙数据 */ // 从原始密匙数据创建DESKeySpec对象 DESKeySpec dks = new DESKeySpec(rawKeyData); // 创建一个密匙工厂，然后用它把DESKeySpec转换成 // 一个SecretKey对象 SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES"); SecretKey key = keyFactory.generateSecret(dks); // 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, key, sr); // 现在，获取数据并加密 byte data[] = plainText;/* 用某种方法获取数据 */ // 正式执行加密操作 byte encryptedData[] = cipher.doFinal(data); return encryptedData; } } DES解密封装 package org.jtool.desutils; import java.security.SecureRandom; import javax.crypto.*; import javax.crypto.spec.DESKeySpec; public class DESDecrypt { private byte[] desKey; public DESDecrypt(byte[] desKey) { this.desKey = desKey; } public byte[] doDecrypt(byte[] encryptText) throws Exception { // DES算法要求有一个可信任的随机数源 SecureRandom sr = new SecureRandom(); byte rawKeyData[] = desKey; /* 用某种方法获取原始密匙数据 */ // 从原始密匙数据创建一个DESKeySpec对象 DESKeySpec dks = new DESKeySpec(rawKeyData); // 创建一个密匙工厂，然后用它把DESKeySpec对象转换成 // 一个SecretKey对象 SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES"); SecretKey key = keyFactory.generateSecret(dks); // 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, key, sr); // 现在，获取数据并解密 byte encryptedData[] = encryptText;/* 获得经过加密的数据 */ // 正式执行解密操作 byte decryptedData[] = cipher.doFinal(encryptedData); return decryptedData; } } DES加解密使用样例 package org.jtool.desutils; /** * */ public class DESTest { public static void main(String[] args) throws Exception { String key = "ABCDEFGH"; String value = "AABBCCDDEE"; DESEncrypt desEncrypt = new DESEncrypt(key.getBytes()); byte[] encryptText = desEncrypt.doEncrypt(value.getBytes()); System.out.println("doEncrypt - " + toHexString(encryptText)); System.out.println("doEncrypt - " + new String(encryptText)); DESDecrypt desDecrypt = new DESDecrypt(key.getBytes()); byte[] decryptText = desDecrypt.doDecrypt(encryptText); System.out.println("doDecrypt - " + new String(decryptText)); System.out.println("doDecrypt - " + toHexString(decryptText)); } /** * 16进制显示数据 * * @param value 字节数组 * @return */ public static String toHexString(byte[] value) { String newString = ""; for (int i = 0; i < value.length; i++) { byte b = value[i]; String str = Integer.toHexString(b); if (str.length() > 2) { str = str.substring(str.length() - 2); } if (str.length() < 2) { str = "0" + str; } newString += str; } return newString.toUpperCase(); } }