1.01-MD5加密的算法

public static String MD5(String key){
    char[] hexDigits={'A','B','C','D','E','F','0','1','2','3','4','5','6','7','8','9'};
    try {
        byte[] btInput=key.getBytes();
        //得到Md5摘要算法的MessageDigest對象
        MessageDigest messageDigest=MessageDigest.getInstance("MD5");
        //使用指定的字節更新摘要
        messageDigest.update(btInput);
        //得到密文
        byte[] md=messageDigest.digest();
        //把密文轉換成十六進制的字符串形式
        int i=md.length;
        char[] str=new char[i*2];
        int j=0;
        for (int k=0;k<i;k++){
            byte b=md[k];
            str[j++]=hexDigits[b>>>4 & 0xf];
            str[j++]=hexDigits[b & 0xf];
        }
        return new String(str);
    }catch (Exception e){
        return null;
    }
 }

@Test
public void run() {
    String s = MD5();
    System.out.println(s);

}