import java.security.MessageDigest;public class MD5Utils {    public final static String calc(String ss){
   //MD5加密算法        String s = ss == null ? "":ss;//如果为空，则返回""        char hexDigists[] = {'0','1','2','3','4','5','6','7','8','9','a','b','c','d',                'e','f'};//字典        try {            byte[] strTemp =s.getBytes();//获取二进制            MessageDigest mdTemp =MessageDigest.getInstance("MD5");            mdTemp.update(strTemp);//执行加密            byte[] md = mdTemp.digest();//加密结果            int j = md.length;//结果长度            char str[] = new char[j*2];//字符数组            int k = 0;            for (int i = 0; i < j; i++) { //将二进制加密结果转化为字符                byte byte0 = md[i];                str[k++] = hexDigists[byte0 >>> 4 &0xf];                str[k++] = hexDigists[byte0 & 0xf];            }            return new String(str);//输出加密后的字符        } catch (Exception e) {            // TODO Auto-generated catch block            return null;        }    }}

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