将 URI 字符串解析为名称-值集合 [英] Parse a URI String into Name-Value Collection

问题描述

我有这样的 URI:

https://google.com.ua/oauth/authorize?client_id=SS&response_type=code&scope=N_FULL&access_type=offline&redirect_uri=http://localhost/Callback

我需要一个包含已解析元素的集合:

I need a collection with parsed elements:

NAME               VALUE
------------------------
client_id          SS
response_type      code
scope              N_FULL
access_type        offline
redirect_uri       http://localhost/Callback

确切地说，我需要 C#/.NET 的 Java 等效项 HttpUtility.ParseQueryString 方法.

To be exact, I need a Java equivalent for the C#/.NET HttpUtility.ParseQueryString method.

推荐答案

如果您正在寻找一种无需使用外部库即可实现的方法，以下代码将对您有所帮助.

If you are looking for a way to achieve it without using an external library, the following code will help you.

public static Map<String, String> splitQuery(URL url) throws UnsupportedEncodingException {
    Map<String, String> query_pairs = new LinkedHashMap<String, String>();
    String query = url.getQuery();
    String[] pairs = query.split("&");
    for (String pair : pairs) {
        int idx = pair.indexOf("=");
        query_pairs.put(URLDecoder.decode(pair.substring(0, idx), "UTF-8"), URLDecoder.decode(pair.substring(idx + 1), "UTF-8"));
    }
    return query_pairs;
}

您可以使用 <map>.get("client_id") 访问返回的 Map，在您的问题中给出的 URL 将返回SS".

You can access the returned Map using <map>.get("client_id"), with the URL given in your question this would return "SS".

更新添加了网址解码

UPDATE 由于这个答案仍然很受欢迎，我对上面的方法做了一个改进版本，它可以处理多个具有相同键的参数和没有值的参数.

UPDATE As this answer is still quite popular, I made an improved version of the method above, which handles multiple parameters with the same key and parameters with no value as well.

public static Map<String, List<String>> splitQuery(URL url) throws UnsupportedEncodingException {
  final Map<String, List<String>> query_pairs = new LinkedHashMap<String, List<String>>();
  final String[] pairs = url.getQuery().split("&");
  for (String pair : pairs) {
    final int idx = pair.indexOf("=");
    final String key = idx > 0 ? URLDecoder.decode(pair.substring(0, idx), "UTF-8") : pair;
    if (!query_pairs.containsKey(key)) {
      query_pairs.put(key, new LinkedList<String>());
    }
    final String value = idx > 0 && pair.length() > idx + 1 ? URLDecoder.decode(pair.substring(idx + 1), "UTF-8") : null;
    query_pairs.get(key).add(value);
  }
  return query_pairs;
}

更新 Java8 版本

public Map<String, List<String>> splitQuery(URL url) {
    if (Strings.isNullOrEmpty(url.getQuery())) {
        return Collections.emptyMap();
    }
    return Arrays.stream(url.getQuery().split("&"))
            .map(this::splitQueryParameter)
            .collect(Collectors.groupingBy(SimpleImmutableEntry::getKey, LinkedHashMap::new, mapping(Map.Entry::getValue, toList())));
}

public SimpleImmutableEntry<String, String> splitQueryParameter(String it) {
    final int idx = it.indexOf("=");
    final String key = idx > 0 ? it.substring(0, idx) : it;
    final String value = idx > 0 && it.length() > idx + 1 ? it.substring(idx + 1) : null;
    return new SimpleImmutableEntry<>(
        URLDecoder.decode(key, "UTF-8"),
        URLDecoder.decode(value, "UTF-8")
    );
}

使用 URL 运行上述方法

Running the above method with the URL

https://stackoverflow.com?param1=value1&param2=&param3=value3&param3

返回此地图:

{param1=["value1"], param2=[null], param3=["value3", null]}

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