IMAP文件夹编解码实现

参考链接: http://hi.baidu.com/hswt/blog/item/e577b0fb4c45ed334f4aea95.html

据原作者讲,是从Perl算法转成的C#算法,我现在没有办法,只能使用Java, 所以又转成Java的实现了,都比较类似,但是由于本人对C#的不熟悉,还是费一些时间在网上找关于C#的正则表达式对象的使用方法.

现在把真正的Java版本放出来, 如果对概念有什么不理解的请直接参考原文章

public class ImapFolderEncoder {
    public static String encode(String folder) {
	String rtn = "", base64;
	int index = 0;
	Pattern regAsis = Pattern.compile("\\G(?:[\\x20-\\x25\\x27-\\x7e])+");
	Pattern reg26 = Pattern.compile("\\G&");
	Pattern regEncode = Pattern.compile("\\G(?:[^\\x20-\\x7e])+");
	Pattern regEq = Pattern.compile("=+$");
	Pattern regSlash = Pattern.compile("\\/");
	while (index < folder.length()) {
	    Matcher m;
	    m = regAsis.matcher(folder);
	    if (m.find(index)) {
		index = index + (m.end() - m.start());
		rtn = rtn + m.group();
		continue;
	    }
	    m = reg26.matcher(folder);
	    if (m.find(index)) {
		index = index + (m.end() - m.start());
		rtn = rtn + "&-";
		continue;
	    }
	    m = regEncode.matcher(folder);
	    if (m.find(index)) {
		index = index + (m.end() - m.start());
		base64 = SimpleUtil.encodeBase64Content(m.group(), "UTF-16BE");
		base64 = base64.replaceAll(regEq.pattern(), "");
		base64 = base64.replaceAll(regSlash.pattern(), ",");
		rtn = rtn + "&" + base64 + "-";
		continue;
	    }
	}
	return rtn;
    }
    
}

public class ImapFolderDecoder {
    public static String decode(String folder) {
	String rtn = "", base64;
	int index = 0;
	Pattern regAsis = Pattern.compile("\\G([^&]+)");
	Pattern reg26 = Pattern.compile("\\G\\&-");
	Pattern regDecode = Pattern.compile("\\G\\&([A-Za-z0-9+,]+)-?");
	Pattern regComma = Pattern.compile(",");
	while (index < folder.length()) {
	    Matcher m;
	    m = regAsis.matcher(folder);
	    if (m.find(index)) {
		index = index + (m.end() - m.start());
		rtn = rtn + m.group();
		continue;
	    }
	    m = reg26.matcher(folder);
	    if (m.find(index)) {
		index = index + (m.end() - m.start());
		rtn = rtn + "&";
		continue;
	    }
	    m = regDecode.matcher(folder);
	    if (m.find(index)) {
		index = index + (m.end() - m.start());
		base64 = m.group().substring(1, m.group().length() - 1);
		base64 = base64.replaceAll(regComma.pattern(), "/");
		int mod = base64.length() % 4;
		int count = 4 - mod;
		while (count > 0) {
		    base64 += "=";
		    count--;
		}
		base64 = SimpleUtil.base64Decode(base64, "UTF-16BE");
		rtn = rtn + base64;
		continue;
	    }
	}
	return rtn;
    }
}