解析查询字符串比看起来要复杂一些，这取决于您希望有多宽容。

首先，查询字符串是ascii字节。每次读入一个字节，然后将它们转换成字符。如果角色是?或者&，然后它表示参数名的开始。如果字符为=，则它表示一个参数值的开始。如果字符为%，则表示已编码字节的开始。这就是棘手的地方。

When you read in a % char you have to read the next two bytes and interpret them as hex digits. That means the next two bytes will be 0-9, a-f or A-F. Glue these two hex digits together to get your byte value. But remember, bytes are not characters. You have to know what encoding was used to encode the characters. The character é does not encode the same in UTF-8 as it does in ISO-8859-1. In general it's impossible to know what encoding was used for a given character set. I always use UTF-8 because my web site is configured to always serve everything using UTF-8 but in practice you can't be certain. Some user-agents will tell you the character encoding in the request; you can try to read that if you have a full HTTP request. If you just have a url in isolation, good luck.

不管怎样，假设您正在使用UTF-8或其他一些多字节字符编码，现在您已经解码了一个已编码的字节，您必须将其放在一边，直到捕获下一个字节。您需要所有已编码的字节放在一起，因为您不能一次正确地对一个字节进行url解码。把所有在一起的字节放在一边，然后立刻解码，重新构建你的角色。

另外，如果你想要宽容一些，并解释用户代理破坏url，它会变得更有趣。例如，一些webmail客户端会对内容进行双重编码。或者使用两个?&=字符(例如:http://yoursite.com/blah??p1==v1&&p2==v2)。如果您想尝试优雅地处理这个问题，就需要向解析器添加更多的逻辑。

在Android上，代码如下所示:

UrlQuerySanitizer sanitzer = new UrlQuerySanitizer(url);
String value = sanitzer.getValue("your_get_parameter");

另外，如果你不想注册每个预期的查询键使用:

sanitzer.setAllowUnregisteredParamaters(true)

在调用之前:

sanitzer.parseUrl(yourUrl)

public static Map<String, List<String>> getUrlParameters(String url)
        throws UnsupportedEncodingException {
    Map<String, List<String>> params = new HashMap<String, List<String>>();
    String[] urlParts = url.split("\\?");
    if (urlParts.length > 1) {
        String query = urlParts[1];
        for (String param : query.split("&")) {
            String pair[] = param.split("=", 2);
            String key = URLDecoder.decode(pair[0], "UTF-8");
            String value = "";
            if (pair.length > 1) {
                value = URLDecoder.decode(pair[1], "UTF-8");
            }
            List<String> values = params.get(key);
            if (values == null) {
                values = new ArrayList<String>();
                params.put(key, values);
            }
            values.add(value);
        }
    }
    return params;
}

对于servlet或JSP页面，您可以使用request.getParameter("paramname")获取查询字符串的键/值对。

String name = request.getParameter("name");

还有其他方法，但我在创建的所有servlet和jsp页面中都是这样做的。

使用番石榴:

Multimap<String,String> parseQueryString(String queryString, String encoding) {
    LinkedListMultimap<String, String> result = LinkedListMultimap.create();

    for(String entry : Splitter.on("&").omitEmptyStrings().split(queryString)) {
        String pair [] = entry.split("=", 2);
        try {
            result.put(URLDecoder.decode(pair[0], encoding), pair.length == 2 ? URLDecoder.decode(pair[1], encoding) : null);
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException(e);
        }
    }

    return result;
}

该方法获取uri并返回票面名称和票面值的映射

  public static Map<String, String> getQueryMap(String uri) {

    String queryParms[] = uri.split("\\?");

    Map<String, String> map = new HashMap<>();// 

    if (queryParms == null || queryParms.length == 0) return map;

    String[] params = queryParms[1].split("&");
    for (String param : params) {
        String name = param.split("=")[0];
        String value = param.split("=")[1];
        map.put(name, value);
    }
    return map;
}