java生成MD5串

package testMD5; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; /** * 采用MD5加密解密 * * @authortfq * @datetime2011-10-13 */ public class TestMD5 { /*** * MD5加码生成32位md5码 */ public static String string2MD5(String inStr) { MessageDigest md5 = null; try { md5 = MessageDigest.getInstance("MD5"); } catch (Exception e) { System.out.println(e.toString()); e.printStackTrace(); return ""; } char[] charArray = inStr.toCharArray(); byte[] byteArray = new byte[charArray.length]; for (int i = 0; i < charArray.length; i++) byteArray[i] = (byte) charArray[i]; byte[] md5Bytes = md5.digest(byteArray); StringBuffer hexValue = new StringBuffer(); for (int i = 0; i < md5Bytes.length; i++) { int val = ((int) md5Bytes[i]) & 0xff; if (val < 16) hexValue.append("0"); hexValue.append(Integer.toHexString(val)); } return hexValue.toString(); } /** * 加密解密算法执行一次加密，执行两次为两次解密 即密通过此方法转变为明文 */ public static String convertMD5(String inStr) { char[] a = inStr.toCharArray(); for (int i = 0; i < a.length; i++) { a[i] = (char) (a[i] ^ 't'); } String s = new String(a); return s; } // 测试主函数 public static void main(String args[]) { String s = new String("456"); System.out.println("原始：" + s); System.out.println("MD5后：" + string2MD5(s)); System.out.println("加密的：" + convertMD5(s)); System.out.println("解密的：" + convertMD5(convertMD5(s))); } }