只是Java 8版本的更新

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, **Collectors**.mapping(Map.Entry::getValue, **Collectors**.toList())));
}

mapping和toList()方法必须用于顶部答案中没有提到的collector。否则它会在IDE中抛出编译错误

org.apache.http.client.utils.URLEncodedUtils

是否有一个知名的库可以帮你做到这一点

import org.apache.hc.client5.http.utils.URLEncodedUtils

String url = "http://www.example.com/something.html?one=1&two=2&three=3&three=3a";

List<NameValuePair> params = URLEncodedUtils.parse(new URI(url), Charset.forName("UTF-8"));

for (NameValuePair param : params) {
  System.out.println(param.getName() + " : " + param.getValue());
}

输出

one : 1
two : 2
three : 3
three : 3a

如果您正在寻找一种不使用外部库的方法来实现它，下面的代码将帮助您。

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”。

添加了UPDATE url -解码

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，它可以处理具有相同键的多个参数和没有值的参数。

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, StandardCharsets.UTF_8),
        URLDecoder.decode(value, StandardCharsets.UTF_8)
    );
}

使用URL运行上述方法

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

返回这个Map:

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

用谷歌番石榴，分成两行:

import java.util.Map;
import com.google.common.base.Splitter;

public class Parser {
    public static void main(String... args) {
        String uri = "https://google.com.ua/oauth/authorize?client_id=SS&response_type=code&scope=N_FULL&access_type=offline&redirect_uri=http://localhost/Callback";
        String query = uri.split("\\?")[1];
        final Map<String, String> map = Splitter.on('&').trimResults().withKeyValueSeparator('=').split(query);
        System.out.println(map);
    }
}

这让你

{client_id=SS, response_type=code, scope=N_FULL, access_type=offline, redirect_uri=http://localhost/Callback}

Netty还提供了一个很好的查询字符串解析器，称为QueryStringDecoder。 在一行代码中，它可以解析问题中的URL。 我喜欢它是因为它不需要捕获或抛出java.net.MalformedURLException。

一句话:

Map<String, List<String>> parameters = new QueryStringDecoder(url).parameters();

查看javadocs: https://netty.io/4.1/api/io/netty/handler/codec/http/QueryStringDecoder.html

下面是一个简短的、完整的、正确的例子:

import io.netty.handler.codec.http.QueryStringDecoder;
import org.apache.commons.lang3.StringUtils;

import java.util.List;
import java.util.Map;

public class UrlParse {

  public static void main(String... args) {
    String url = "https://google.com.ua/oauth/authorize?client_id=SS&response_type=code&scope=N_FULL&access_type=offline&redirect_uri=http://localhost/Callback";
    QueryStringDecoder decoder = new QueryStringDecoder(url);
    Map<String, List<String>> parameters = decoder.parameters();
    print(parameters);
  }

  private static void print(final Map<String, List<String>> parameters) {
    System.out.println("NAME               VALUE");
    System.out.println("------------------------");
    parameters.forEach((key, values) ->
        values.forEach(val ->
            System.out.println(StringUtils.rightPad(key, 19) + val)));
  }
}

而产生

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

Eclipse Jersey REST框架通过UriComponent支持这一点。例子:

import org.glassfish.jersey.uri.UriComponent;

String uri = "https://google.com.ua/oauth/authorize?client_id=SS&response_type=code&scope=N_FULL&access_type=offline&redirect_uri=http://localhost/Callback";
MultivaluedMap<String, String> params = UriComponent.decodeQuery(URI.create(uri), true);
for (String key : params.keySet()) {
  System.out.println(key + ": " + params.getFirst(key));
}