android之字符串的一些转码

import java.security.MessageDigest;

public class StringUtils {

    public static String replaceUrlWithPlus(String url) {       
        if (url != null) {
            return url.replaceAll("http://(.)*?/", "").replaceAll("[.:/,%?&=]", "+").replaceAll("[+]+", "+");
        }
        return null;
    }
    

    public static String EncodeMD5(String text) throws Exception {
        MessageDigest md = MessageDigest.getInstance("MD5");
        md.update(text.getBytes("US-ASCII"));
        byte[] digest = md.digest();
        StringBuffer md5 = new StringBuffer();
        for (int i = 0; i < digest.length; i++) {
            md5.append(Character.forDigit((digest[i] & 0xF0) >> 4, 16));
            md5.append(Character.forDigit((digest[i] & 0xF), 16));
        }
        return md5.toString();
    }


    public static String EncodeMD5ASCII(String text) throws Exception {
        MessageDigest md = MessageDigest.getInstance("MD5");
        md.update(text.getBytes("US-ASCII"));
        byte[] digest = md.digest();
        return new String(digest, "US-ASCII");
    }


    public static String DecodeMD5Hex(String text) throws Exception {
        byte[] digest = text.getBytes();
        StringBuffer md5 = new StringBuffer();
        for (int i = 0; i < digest.length; i++) {
            md5.append(Character.forDigit((digest[i] & 0xF0) >> 4, 16));
            md5.append(Character.forDigit((digest[i] & 0xF), 16));
        }
        return md5.toString();
    }
}