I've got the URI like this:
https://google.com.ua/oauth/authorize?client_id=SS&response_type=code&scope=N_FULL&access_type=offline&redirect_uri=http://localhost/Callback
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
To be exact, I need a Java equivalent for the C#/.NET HttpUtility.ParseQueryString
method.
This question is related to
java
parsing
uri
namevaluecollection
Netty also provides a nice query string parser called QueryStringDecoder
.
In one line of code, it can parse the URL in the question.
I like because it doesn't require catching or throwing java.net.MalformedURLException
.
In one line:
Map<String, List<String>> parameters = new QueryStringDecoder(url).parameters();
See javadocs here: https://netty.io/4.1/api/io/netty/handler/codec/http/QueryStringDecoder.html
Here is a short, self contained, correct example:
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)));
}
}
which generates
NAME VALUE
------------------------
client_id SS
response_type code
scope N_FULL
access_type offline
redirect_uri http://localhost/Callback
For Android, if you are using OkHttp in your project. You might get a look at this. It simple and helpful.
final HttpUrl url = HttpUrl.parse(query);
if (url != null) {
final String target = url.queryParameter("target");
final String id = url.queryParameter("id");
}
Kotlin's Answer with initial reference from https://stackoverflow.com/a/51024552/3286489, but with improved version by tidying up codes and provides 2 versions of it, and use immutable collection operations
Use java.net.URI
to extract the Query. Then use the below provided extension functions
page2&page3
will get {page=3}
, use the below extension function fun URI.getQueryMap(): Map<String, String> {
if (query == null) return emptyMap()
return query.split("&")
.mapNotNull { element -> element.split("=")
.takeIf { it.size == 2 && it.none { it.isBlank() } } }
.associateBy({ it[0].decodeUTF8() }, { it[1].decodeUTF8() })
}
private fun String.decodeUTF8() = URLDecoder.decode(this, "UTF-8") // decode page=%22ABC%22 to page="ABC"
page2&page3
will get {page=[2, 3]}
fun URI.getQueryMapList(): Map<String, List<String>> {
if (query == null) return emptyMap()
return query.split("&")
.distinct()
.mapNotNull { element -> element.split("=")
.takeIf { it.size == 2 && it.none { it.isBlank() } } }
.groupBy({ it[0].decodeUTF8() }, { it[1].decodeUTF8() })
}
private fun String.decodeUTF8() = URLDecoder.decode(this, "UTF-8") // decode page=%22ABC%22 to page="ABC"
The way to use it as below
val uri = URI("schema://host/path/?page=&page=2&page=2&page=3")
println(uri.getQueryMapList()) // Result is {page=[2, 3]}
println(uri.getQueryMap()) // Result is {page=3}
If you are using servlet doGet try this
request.getParameterMap()
Returns a java.util.Map of the parameters of this request.
Returns: an immutable java.util.Map containing parameter names as keys and parameter values as map values. The keys in the parameter map are of type String. The values in the parameter map are of type String array.
(Java doc)
I had a go at a Kotlin version seeing how this is the top result in Google.
@Throws(UnsupportedEncodingException::class)
fun splitQuery(url: URL): Map<String, List<String>> {
val queryPairs = LinkedHashMap<String, ArrayList<String>>()
url.query.split("&".toRegex())
.dropLastWhile { it.isEmpty() }
.map { it.split('=') }
.map { it.getOrEmpty(0).decodeToUTF8() to it.getOrEmpty(1).decodeToUTF8() }
.forEach { (key, value) ->
if (!queryPairs.containsKey(key)) {
queryPairs[key] = arrayListOf(value)
} else {
if(!queryPairs[key]!!.contains(value)) {
queryPairs[key]!!.add(value)
}
}
}
return queryPairs
}
And the extension methods
fun List<String>.getOrEmpty(index: Int) : String {
return getOrElse(index) {""}
}
fun String.decodeToUTF8(): String {
URLDecoder.decode(this, "UTF-8")
}
I wasn't happy with the code provided by @Pr0gr4mm3r in https://stackoverflow.com/a/13592567/1211082 . The Stream-based solution does not do URLDecoding, the mutable version clumpsy.
Thus I elaborated a solution that
Map<String, List<Optional<String>>>
Optional.empty()
instead of null
)URLdecode
UnsupportedEncodingException
into a runtime exception RuntimeUnsupportedEncodingException
that allows interplay with stream. (Wrapping regular function into functions throwing checked exceptions is a pain. And Scala Try
is not available in the Java language default.)import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.util.*;
import static java.util.stream.Collectors.*;
public class URIParameterDecode {
/**
* Decode parameters in query part of a URI into a map from parameter name to its parameter values.
* For parameters that occur multiple times each value is collected.
* Proper decoding of the parameters is performed.
*
* Example
* <pre>a=1&b=2&c=&a=4</pre>
* is converted into
* <pre>{a=[Optional[1], Optional[4]], b=[Optional[2]], c=[Optional.empty]}</pre>
* @param query the query part of an URI
* @return map of parameters names into a list of their values.
*
*/
public static Map<String, List<Optional<String>>> splitQuery(String query) {
if (query == null || query.isEmpty()) {
return Collections.emptyMap();
}
return Arrays.stream(query.split("&"))
.map(p -> splitQueryParameter(p))
.collect(groupingBy(e -> e.get0(), // group by parameter name
mapping(e -> e.get1(), toList())));// keep parameter values and assemble into list
}
public static Pair<String, Optional<String>> splitQueryParameter(String parameter) {
final String enc = "UTF-8";
List<String> keyValue = Arrays.stream(parameter.split("="))
.map(e -> {
try {
return URLDecoder.decode(e, enc);
} catch (UnsupportedEncodingException ex) {
throw new RuntimeUnsupportedEncodingException(ex);
}
}).collect(toList());
if (keyValue.size() == 2) {
return new Pair(keyValue.get(0), Optional.of(keyValue.get(1)));
} else {
return new Pair(keyValue.get(0), Optional.empty());
}
}
/** Runtime exception (instead of checked exception) to denote unsupported enconding */
public static class RuntimeUnsupportedEncodingException extends RuntimeException {
public RuntimeUnsupportedEncodingException(Throwable cause) {
super(cause);
}
}
/**
* A simple pair of two elements
* @param <U> first element
* @param <V> second element
*/
public static class Pair<U, V> {
U a;
V b;
public Pair(U u, V v) {
this.a = u;
this.b = v;
}
public U get0() {
return a;
}
public V get1() {
return b;
}
}
}
... and for the sake of completeness I can not resist to provide the solution in Scala that dominates by brevity and beauty
import java.net.URLDecoder
object Decode {
def main(args: Array[String]): Unit = {
val input = "a=1&b=2&c=&a=4";
println(separate(input))
}
def separate(input: String) : Map[String, List[Option[String]]] = {
case class Parameter(key: String, value: Option[String])
def separateParameter(parameter: String) : Parameter =
parameter.split("=")
.map(e => URLDecoder.decode(e, "UTF-8")) match {
case Array(key, value) => Parameter(key, Some(value))
case Array(key) => Parameter(key, None)
}
input.split("&").toList
.map(p => separateParameter(p))
.groupBy(p => p.key)
.mapValues(vs => vs.map(p => p.value))
}
}
Just an update to the Java 8 version
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 and toList() methods have to be used with Collectors which was not mentioned in the top answer. Otherwise it would throw compilation error in IDE
If you are using Spring, add an argument of type @RequestParam Map<String,String>
to your controller method, and Spring will construct the map for you!
If you are using Spring Framework:
public static void main(String[] args) {
String uri = "http://my.test.com/test?param1=ab¶m2=cd¶m2=ef";
MultiValueMap<String, String> parameters =
UriComponentsBuilder.fromUriString(uri).build().getQueryParams();
List<String> param1 = parameters.get("param1");
List<String> param2 = parameters.get("param2");
System.out.println("param1: " + param1.get(0));
System.out.println("param2: " + param2.get(0) + "," + param2.get(1));
}
You will get:
param1: ab
param2: cd,ef
If you're using Java 8 and you're willing to write a few reusable methods, you can do it in one line.
private Map<String, List<String>> parse(final String query) {
return Arrays.asList(query.split("&")).stream().map(p -> p.split("=")).collect(Collectors.toMap(s -> decode(index(s, 0)), s -> Arrays.asList(decode(index(s, 1))), this::mergeLists));
}
private <T> List<T> mergeLists(final List<T> l1, final List<T> l2) {
List<T> list = new ArrayList<>();
list.addAll(l1);
list.addAll(l2);
return list;
}
private static <T> T index(final T[] array, final int index) {
return index >= array.length ? null : array[index];
}
private static String decode(final String encoded) {
try {
return encoded == null ? null : URLDecoder.decode(encoded, "UTF-8");
} catch(final UnsupportedEncodingException e) {
throw new RuntimeException("Impossible: UTF-8 is a required encoding", e);
}
}
But that's a pretty brutal line.
Given the URL to analyse:
URL url = new URL("https://google.com.ua/oauth/authorize?client_id=SS&response_type=code&scope=N_FULL&access_type=offline&redirect_uri=http://localhost/Callback");
This solution collects a list of pairs:
List<Map.Entry<String, String>> list = Pattern.compile("&")
.splitAsStream(url.getQuery())
.map(s -> Arrays.copyOf(s.split("=", 2), 2))
.map(o -> Map.entry(decode(o[0]), decode(o[1])))
.collect(Collectors.toList());
This solution on the other hand collects a map (given that in a url there can be more parameters with same name but different values).
Map<String, List<String>> list = Pattern.compile("&")
.splitAsStream(url.getQuery())
.map(s -> Arrays.copyOf(s.split("=", 2), 2))
.collect(groupingBy(s -> decode(s[0]), mapping(s -> decode(s[1]), toList())));
Both the solutions must use an utility function to properly decode the parameters.
private static String decode(final String encoded) {
return Optional.ofNullable(encoded)
.map(e -> URLDecoder.decode(e, StandardCharsets.UTF_8))
.orElse(null);
}
If you come across Android Java SDK;
This solution might be too late but it's the latest solution today.
You can use the below way to get the value of the some
query, if there is no value it will return null.
String some = Uri.parse(url).getQueryParameter("some");
In order to get all the names of the query collection.
Set<String> names = Uri.parse(url).getQueryParameterNames();
Answering here because this is a popular thread. This is a clean solution in Kotlin that uses the recommended UrlQuerySanitizer
api. See the official documentation. I have added a string builder to concatenate and display the params.
var myURL: String? = null
if (intent.hasExtra("my_value")) {
myURL = intent.extras.getString("my_value")
} else {
myURL = intent.dataString
}
val sanitizer = UrlQuerySanitizer(myURL)
// We don't want to manually define every expected query *key*, so we set this to true
sanitizer.allowUnregisteredParamaters = true
val parameterNamesToValues: List<UrlQuerySanitizer.ParameterValuePair> = sanitizer.parameterList
val parameterIterator: Iterator<UrlQuerySanitizer.ParameterValuePair> = parameterNamesToValues.iterator()
// Helper simply so we can display all values on screen
val stringBuilder = StringBuilder()
while (parameterIterator.hasNext()) {
val parameterValuePair: UrlQuerySanitizer.ParameterValuePair = parameterIterator.next()
val parameterName: String = parameterValuePair.mParameter
val parameterValue: String = parameterValuePair.mValue
// Append string to display all key value pairs
stringBuilder.append("Key: $parameterName\nValue: $parameterValue\n\n")
}
// Set a textView's text to display the string
val paramListString = stringBuilder.toString()
val textView: TextView = findViewById(R.id.activity_title) as TextView
textView.text = "Paramlist is \n\n$paramListString"
// to check if the url has specific keys
if (sanitizer.hasParameter("type")) {
val type = sanitizer.getValue("type")
println("sanitizer has type param $type")
}
Using above mentioned comments and solutions, I am storing all the query parameters using Map<String, Object> where Objects either can be string or Set<String>. The solution is given below. It is recommended to use some kind of url validator to validate the url first and then call convertQueryStringToMap method.
private static final String DEFAULT_ENCODING_SCHEME = "UTF-8";
public static Map<String, Object> convertQueryStringToMap(String url) throws UnsupportedEncodingException, URISyntaxException {
List<NameValuePair> params = URLEncodedUtils.parse(new URI(url), DEFAULT_ENCODING_SCHEME);
Map<String, Object> queryStringMap = new HashMap<>();
for(NameValuePair param : params){
queryStringMap.put(param.getName(), handleMultiValuedQueryParam(queryStringMap, param.getName(), param.getValue()));
}
return queryStringMap;
}
private static Object handleMultiValuedQueryParam(Map responseMap, String key, String value) {
if (!responseMap.containsKey(key)) {
return value.contains(",") ? new HashSet<String>(Arrays.asList(value.split(","))) : value;
} else {
Set<String> queryValueSet = responseMap.get(key) instanceof Set ? (Set<String>) responseMap.get(key) : new HashSet<String>();
if (value.contains(",")) {
queryValueSet.addAll(Arrays.asList(value.split(",")));
} else {
queryValueSet.add(value);
}
return queryValueSet;
}
}
The shortest way I've found is this one:
MultiValueMap<String, String> queryParams =
UriComponentsBuilder.fromUriString(url).build().getQueryParams();
UPDATE: UriComponentsBuilder
comes from Spring. Here the link.
Here is my solution with reduce and Optional:
private Optional<SimpleImmutableEntry<String, String>> splitKeyValue(String text) {
String[] v = text.split("=");
if (v.length == 1 || v.length == 2) {
String key = URLDecoder.decode(v[0], StandardCharsets.UTF_8);
String value = v.length == 2 ? URLDecoder.decode(v[1], StandardCharsets.UTF_8) : null;
return Optional.of(new SimpleImmutableEntry<String, String>(key, value));
} else
return Optional.empty();
}
private HashMap<String, String> parseQuery(URI uri) {
HashMap<String, String> params = Arrays.stream(uri.getQuery()
.split("&"))
.map(this::splitKeyValue)
.filter(Optional::isPresent)
.map(Optional::get)
.reduce(
// initial value
new HashMap<String, String>(),
// accumulator
(map, kv) -> {
map.put(kv.getKey(), kv.getValue());
return map;
},
// combiner
(a, b) -> {
a.putAll(b);
return a;
});
return params;
}
Optional<SimpleImmutableEntry<String, String>>
to ignore garbage laterIn case you ask, reduce requires this weird combiner in the last parameter, which is only used in parallel streams. Its goal is to merge two intermediate results (here HashMap).
On Android, there is a Uri class in package android.net . Note that Uri is part of android.net, while URI is part of java.net .
Uri class has many functions to extract key-value pairs from a query.
Following function returns key-value pairs in the form of HashMap.
In Java:
Map<String, String> getQueryKeyValueMap(Uri uri){
HashMap<String, String> keyValueMap = new HashMap();
String key;
String value;
Set<String> keyNamesList = uri.getQueryParameterNames();
Iterator iterator = keyNamesList.iterator();
while (iterator.hasNext()){
key = (String) iterator.next();
value = uri.getQueryParameter(key);
keyValueMap.put(key, value);
}
return keyValueMap;
}
In Kotlin:
fun getQueryKeyValueMap(uri: Uri): HashMap<String, String> {
val keyValueMap = HashMap<String, String>()
var key: String
var value: String
val keyNamesList = uri.queryParameterNames
val iterator = keyNamesList.iterator()
while (iterator.hasNext()) {
key = iterator.next() as String
value = uri.getQueryParameter(key) as String
keyValueMap.put(key, value)
}
return keyValueMap
}
If you happen to have cxf-core on the classpath and you know you have no repeated query params, you may want to use UrlUtils.parseQueryString.
use google Guava and do it in 2 lines:
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);
}
}
which gives you
{client_id=SS, response_type=code, scope=N_FULL, access_type=offline, redirect_uri=http://localhost/Callback}
is a well known library that can do it for you
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());
}
Outputs
one : 1
two : 2
three : 3
three : 3a
Source: Stackoverflow.com