What I'm trying to do: I have a set of golf club objects(~60 clubs). Depending on the club name and club level(1-10 levels), each one will have a different maxmultiplier and minmultiplier value associated with it that I will need to perform calculations.
What I've thought about:
Using switch statement for the club levels and a hashmap to pair the club name with an array of the multipliers in order to retrieve the correct values. Issue I have with this would be that I would have to create ~60 separate 2item arrays for the multipliers. Thought about 2d arrays and so forth but I'm at the point where it feels like I'm going in circles. I know I CAN get it to work through brute force but I'm trying to work on efficiency. Is there a way to set this up in a localized way(table-like structure) that would make it easy to retrieve?
Things to Note: Java is my first language,I'm trying to learn, I'm at the skill level where I can MAKE things work but am transitioning into learning best practices. So for answers If we could stick with basic/intermediate java ideas that would be appreciated. But after I get it working next step will be implementing serializable to store data outside the program and learning that, followed by storing information in a SQL database which ultimately seems the easiest in my mind using a table.
Here is some of my code:
/*
* Creates all the clubs to be used in the app
*/
public ClubSet() {
clubMap = new HashMap<String, String[]>(100, (float) 0.8);
clubMap.put("DRIVER", driverArray);//all the club names of driver type
clubMap.put("WOOD", woodArray);
clubMap.put("LONG", longArray);
clubMap.put("SHORT", shortArray);
clubMap.put("WEDGE", wedgeArray);
clubMap.put("ROUGH", roughArray);
clubMap.put("SAND", sandArray);
for (HashMap.Entry<String, String[]> entry : clubMap.entrySet()) {
for (String clubName : entry.getValue()) {
Club club = new Club(entry.getKey(), clubName);
this.put(club, club.getClubType());
}
}
}
/*
* Returns a set of all clubs according to clubtypre(e.g. Driver,Wood,Long
* Iron,etc)
*/
public HashSet<Club> getClubSet(String clubType) {
HashSet<Club> clubSet = new HashSet<Club>();
if (this.containsValue(clubType)) {
for (HashMap.Entry<Club, String> entry : this.entrySet()) {
if (entry.getValue().equalsIgnoreCase(clubType)) {
clubSet.add(entry.getKey());
}
}
}
return clubSet;
}
}
public class Club {
private String clubType;
private String clubName;
private int level;
private ImageIcon imageIcon;
private String rarity;
private double maxMultiplier;
private double minMultiplier;
private HashMap<String, String[]> rarityMap;
private final String[] starterArray = new String[] { "BEGINNER DRIVER", "BEGINNER WOOD", "BEGINNER LONG",
"BEGINNER SHORT", "BEGINNER WEDGE", "BEGINNER ROUGH", "BEGINNER SAND" };
private final String[] commonArray = new String[] { "ROCKET", "QUARTERBACK", "VIPER", "SNIPER", "BACKBONE",
"SATURN", "RUNNER", "CLAW", "DART", "SKEWER", "MACHETE", "DESERT STORM", "SAND LIZARD" };
private final String[] rareArray = new String[] { "EXTRA MILE", "ROCK", "BIG DAWG", "GUARDIAN", "GOLIATH",
"GRIZZLY", "APACHE", "THORN", "HORNET", "DOWN-IN-ONE", "RAPIER", "ROUGHCUTTER", "RAZOR", "NIRVANA",
"MALIBU", "HOUDINI" };
private final String[] epicArray = new String[] { "APOCALYPSE", "BIG TOPPER", "THOR'S HAMMER", "HORIZON",
"CATACLYSM", "HAMMERHEAD", "GRIM REAPER", "B52", "TSUNAMI", "KINGFISHER", "FALCON", "FIREFLY", "BOOMERANG",
"ENDBRINGER", "JUNGLIST", "OFF ROADER", "AMAZON", "CASTAWAY", "SAHARA", "SPITFIRE" };
public Club() {
this.clubType = null;
this.clubName = null;
this.level = 1;
rarity = null;
// maxMultiplier = 0;
// minMultiplier = 0;
}
public Club(String clubType, String clubName) {
this.clubName = clubName;
this.clubType = clubType;
this.level = 1;
if (Arrays.asList(starterArray).contains(clubName)) {
this.rarity = "STARTER";
} else if (Arrays.asList(commonArray).contains(clubName)) {
this.rarity = "COMMON";
} else if (Arrays.asList(rareArray).contains(clubName)) {
this.rarity = "RARE";
} else if (Arrays.asList(epicArray).contains(clubName)) {
this.rarity = "EPIC";
}
// setMultipliers(clubName);
}
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.
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;
}
You can access the returned Map using <map>.get("client_id"), with the URL given in your question this would return "SS".
UPDATE URL-Decoding added
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;
}
UPDATE Java8 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, 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)
);
}
Running the above method with the URL
https://stackoverflow.com?param1=value1¶m2=¶m3=value3¶m3
returns this Map:
{param1=["value1"], param2=[null], param3=["value3", null]}
org.apache.http.client.utils.URLEncodedUtils
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
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
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}
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.
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");
}
PLAIN Java 11
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);
}
On Android, there is a Uri class in package android.net . Note that Uri is part of android.net, whereas 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 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)
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
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.
There a new version of Apache HTTP client - org.apache.httpcomponents.client5 - where URLEncodedUtils is now deprecated. URIBuilder should be used instead:
import org.apache.hc.core5.http.NameValuePair;
import org.apache.hc.core5.net.URIBuilder;
private static Map<String, String> getQueryParameters(final String url) throws URISyntaxException {
return new URIBuilder(new URI(url), StandardCharsets.UTF_8).getQueryParams()
.stream()
.collect(Collectors.toMap(NameValuePair::getName,
nameValuePair -> URLDecoder.decode(nameValuePair.getValue(), StandardCharsets.UTF_8)));
}
A ready-to-use solution for decoding of URI query part (incl. decoding and multi parameter values)
Comments
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
Can decompose a URI query part into a Map<String, List<Optional<String>>>
Can handle multiple values for the same parameter name
Can represent parameters without a value properly (Optional.empty() instead of null)
Decodes parameter names and values correctly via URLdecode
Is based on Java 8 Streams
Is directly usable (see code including imports below)
Allows for proper error handling (here via turning a checked exception UnsupportedEncodingExceptioninto 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.)
Java Code
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;
}
}
}
Scala Code
... 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))
}
}
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;
}
}
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")
}
Also, I would recommend regex based implementation of URLParser
import java.util.regex.Matcher;
import java.util.regex.Pattern;
class URLParser {
private final String query;
public URLParser(String query) {
this.query = query;
}
public String get(String name) {
String regex = "(?:^|\\?|&)" + name + "=(.*?)(?:&|$)";
Pattern pattern = Pattern.compile(regex);
Matcher matcher = pattern.matcher(this.query);
if (matcher.find()) {
return matcher.group(1);
}
return "";
}
}
This class is easy to use. It just needs the URL or the query string on initialization and parses value by given key.
class Main {
public static void main(String[] args) {
URLParser parser = new URLParser("https://www.google.com/search?q=java+parse+url+params&oq=java+parse+url+params&aqs=chrome..69i57j0i10.18908j0j7&sourceid=chrome&ie=UTF-8");
System.out.println(parser.get("q")); // java+parse+url+params
System.out.println(parser.get("sourceid")); // chrome
System.out.println(parser.get("ie")); // UTF-8
}
}
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
Assuming you only want the last value of query i.e. 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"
Assuming you want a list of all value for the query i.e. 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}
There are plenty of answers which work for your query as you've indicated when it has single parameter definitions. In some applications it may be useful to handle a few extra query parameter edge cases such as:
list of parameter values such as param1¶m1=value¶m1= meaning param1 is set to List.of("", "value", "")
invalid permutations such as querypath?&=&&=noparamname&.
use empty string not null in maps a= means "a" is List.of("") to match web servlet handling
This uses a Stream with filters and groupingBy to collect to Map<String, List<String>>:
public static Map<String, List<String>> getParameterValues(URL url) {
return Arrays.stream(url.getQuery().split("&"))
.map(s -> s.split("="))
// filter out empty parameter names (as in Tomcat) "?&=&&=value&":
.filter(arr -> arr.length > 0 && arr[0].length() > 0)
.collect(Collectors.groupingBy(arr -> URLDecoder.decode(arr[0], StandardCharsets.UTF_8),
// drop this line for not-name definition order Map:
LinkedHashMap::new,
Collectors.mapping(arr -> arr.length < 2 ? "" : URLDecoder.decode(arr[1], StandardCharsets.UTF_8), Collectors.toList())));
}
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!
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
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")
}
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;
}
I ignore duplicate parameters (I take the last one).
I use Optional<SimpleImmutableEntry<String, String>> to ignore garbage later
The reduction start with an empty map, then populate it on each SimpleImmutableEntry
In 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).
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.
The Eclipse Jersey REST framework supports this through UriComponent. Example:
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));
}
If just want the parameters after the URL from a String. Then the following code will work. I am just assuming the simple Url. I mean no hard and fast checking and decoding. Like in one of my test case I got the Url and I know I just need the value of the paramaters. The url was simple. No encoding decoding needed.
String location = "https://google.com.ua/oauth/authorize?client_id=SS&response_type=code&scope=N_FULL&access_type=offline&redirect_uri=http://localhost/Callback";
String location1 = "https://stackoverflow.com?param1=value1¶m2=value2¶m3=value3";
String location2 = "https://stackoverflow.com?param1=value1¶m2=¶m3=value3¶m3";
Map<String, String> paramsMap = Stream.of(location)
.filter(l -> l.indexOf("?") != -1)
.map(l -> l.substring(l.indexOf("?") + 1, l.length()))
.flatMap(q -> Pattern.compile("&").splitAsStream(q))
.map(s -> s.split("="))
.filter(a -> a.length == 2)
.collect(Collectors.toMap(
a -> a[0],
a -> a[1],
(existing, replacement) -> existing + ", " + replacement,
LinkedHashMap::new
));
System.out.println(paramsMap);
Thanks
That seems tidy to me the best way:
static Map<String, String> decomposeQueryString(String query, Charset charset) {
return Arrays.stream(query.split("&"))
.map(pair -> pair.split("=", 2))
.collect(Collectors.toMap(
pair -> URLDecoder.decode(pair[0], charset),
pair -> pair.length > 1 ? URLDecoder.decode(pair[1], charset) : null)
);
}
The prerequisite is that your query syntax does not allow repeated parameters.
The Hutool framework supports this through HttpUtil. Example:
import cn.hutool.http.HttpUtil;
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";
Map<String, List<String>> stringListMap = HttpUtil.decodeParams(url, "UTF-8");
System.out.println("decodeParams：" + stringListMap);
You will get:
decodeParams：{client_id=[SS], response_type=[code], scope=[N_FULL], access_type=[offline], redirect_uri=[http://localhost/Callback]}
A kotlin version
of the answer Answer by matthias provided
fun decomposeQueryString(query: String, charset: Charset): Map<String, String?> {
return if (query.split("?").size <= 1)
emptyMap()
else {
query.split("?")[1]
.split("&")
.map { it.split(Pattern.compile("="), 2) }
.associate {
Pair(
URLDecoder.decode(it[0], charset.name()),
if (it.size > 1) URLDecoder.decode(it[1], charset.name()) else null
)
}
}
}
This takes of the first parameter after the question mark '?' as well.
Plain Java, No Special Libraries, Nothing Fancy
// assumes you are parsing a line that looks like:
// /path/resource?key=value¶meter=value
// which you got from a request header line that looks like:
// GET /path/resource?key=value¶meter=value HTTP/1.1
public HashMap<String, String> parseQuery(String path){
if(path == null || path.isEmpty()){ //basic sanity check
return null;
}
int indexOfQ = path.indexOf("?"); //where the query string starts
if(indexOfQ == -1){return null;} //check query exists
String queryString = path.substring(indexOfQ + 1);
String[] queryStringArray = queryString.split("&");
Map<String, String> kvMap = new HashMap<>();
for(String kvString : queryStringArray){
int indexOfE = kvString.indexOf("="); //check query is formed correctly
if(indexOfE == -1 || indexOfE == 0){return null;}
String[] kvPairArray = kvString.split("=");
kvMap.put(kvPairArray[0], kvPairArray[1]);
}
return kvMap;
}
org.keycloak.common.util.UriUtils
I had to parse URIs and Query Parameters in a Keycloak extension and found this utility classes very useful:
org.keycloak.common.util.UriUtils:
static MultivaluedHashMap<String,String> decodeQueryString(String queryString)
There is also a useful method to delete one query parameter:
static String stripQueryParam(String url, String name)
And to parse the URL there is
org.keycloak.common.util.KeycloakUriBuilder:
KeycloakUriBuilder uri(String uriTemplate)
String getQuery()
and lots of other goodies.
I would like to test method which use another one? I tried do it using Mockito like below:
EDIT: Full method
public String createUrlAddress(TypeOfInformation typeOfInformation, String icao) {
switch (typeOfInformation) {
case METAR:
urlAddress = StaticValues.MAIN_URL_ADDRESS_FOR_METAR + icao;
break;
case TAF:
urlAddress = StaticValues.MAIN_URL_ADDRESS_FOR_TAF + icao + StaticValues.TAF_4_HOURS_BEFORE_NOW;
break;
case CITY_PAIR_METAR:
urlAddress = StaticValues.MAIN_URL_ADDRESS_FOR_CITY_PAIRS
+ pc.getDepartureAndArrivalTime().get("departureTime") //get departure time from hashmap
+ StaticValues.END_TIME_STRING
+ pc.getDepartureAndArrivalTime().get("arrivalTime")
+ StaticValues.STATION_STRING
+ pc.getOriginIcao()
+ ","
+ pc.getDestinationIcao()
+ StaticValues.MOST_RECENT_FOR_TYPED_STATIONS;
System.out.println(urlAddress);
break;
case CITY_PAIR_TAFS:
urlAddress = StaticValues.MAIN_URL_ADDRESS_FOR_CITY_PAIRS_TAFS
+ pc.getDepartureAndArrivalTime().get("departureTime")
+ StaticValues.END_TIME_STRING
+ pc.getDepartureAndArrivalTime().get("arrivalTime")
+ StaticValues.STATION_STRING
+ pc.getOriginIcao()
+ ",%20"
+ pc.getDestinationIcao()
+ StaticValues.MOST_RECENT_FOR_TYPED_STATIONS_TAFS;
System.out.println(urlAddress);
break;
default:
System.out.println("Wrong Type of informations");
}
return urlAddress;
}
Tests:
#Test
public void forGivenTypeOfInformationAndIcaoReturnUrl() {
HashMap<String,Long> departureAndArrivalTimeTest = new HashMap<>();
departureAndArrivalTimeTest.put("departureTime", 1499264449L);
departureAndArrivalTimeTest.put("arrivalTime", 1499282449L);
PageControllerForNearestCity pcSpy = Mockito.spy(pc);
Mockito.when(pcSpy.getDepartureAndArrivalTime()).thenReturn(departureAndArrivalTimeTest);
Mockito.when(pcSpy.getOriginIcao()).thenReturn("EPWA");
Mockito.when(pcSpy.getDestinationIcao()).thenReturn("EDDF");
assertThat(StaticValuesForTest.URL_ADDRESS_FOR_CITY_PAIR_METAR).isEqualTo(xmlParser.createUrlAddress(TypeOfInformation.CITY_PAIR_METAR, "EPGD")); }
How can I use my mocks in that case? Is it good approach or I have to do it in other way? I would like to add that I won't add these variables as arguments for this method.
PS I thought that the method has only one resposibility, just create a string, am I wrong? Should it be divided into another one like a "Service"?
Thank you for support
Your test enters too much in implementation details.
You mock the own processings/logic of your method. So it makes the test brittle and we can wonder what you assert really.
Besides, the test is complicated to read and to maintain.
At last, the processing associated to each case matters. It is the main logic of your method :
case CITY_PAIR_METAR:
urlAddress = StaticValues.MAIN_URL_ADDRESS_FOR_CITY_PAIRS
+ pc.getDepartureAndArrivalTime().get("departureTime") //get departure time from hashmap
+ StaticValues.END_TIME_STRING
+ pc.getDepartureAndArrivalTime().get("arrivalTime") //get arrival time from hashmap
+ StaticValues.STATION_STRING
+ pc.getOriginIcao()
+ ","
+ pc.getDestinationIcao()
+ StaticValues.MOST_RECENT_FOR_TYPED_STATIONS;
System.out.println(urlAddress);
It should be tested without mocking as you actually doing.
To do it, you should separate responsabilities by introducing a new class.
The actual class should only have a controller/dispatcher role and the new class should perform the logic with a public method by case.
In this way, you class under test could have a dependency on this class and you could mock them in a straight way.
Your actual method could finally look like :
private AddressService addressService;
public String createUrlAddress(TypeOfInformation typeOfInformation, String icao) {
switch (typeOfInformation) {
(...)
case CITY_PAIR_METAR:
urlAddress = addressService.createUrl();
break;
(...)
default:
System.out.println("Wrong Type of informations");
}
return urlAddress;
}
#rafaelim After your response I updated my test class and injected mock to the class like below:
#Before
public void setUp() throws Exception {
departureAndArrivalTimeTest = new HashMap<>();
xmlParser = new XmlParser();
pc = new PageControllerForNearestCity();
departureAndArrivalTimeTest.put("departureTime", 1499264449L); //second arg dep time in sec
departureAndArrivalTimeTest.put("arrivalTime", 1499282449L); //second arg arr time in sec
}
#Test
public void forGivenTypeOfInformationAndIcaoReturnUrl() {
PageControllerForNearestCity pcSpy = Mockito.spy(pc);
xmlParser.setPc(pcSpy);
Mockito.when(pcSpy.getDepartureAndArrivalTime()).thenReturn(departureAndArrivalTimeTest);
Mockito.when(pcSpy.getOriginIcao()).thenReturn("EPWA");
Mockito.when(pcSpy.getDestinationIcao()).thenReturn("EDDF");
assertThat(StaticValuesForTest.URL_ADDRESS_FOR_METAR).isEqualTo(xmlParser.createUrlAddress(TypeOfInformation.METAR, "EPGD"));
assertThat(StaticValuesForTest.URL_ADDRESS_FOR_TAF).isEqualTo(xmlParser.createUrlAddress(TypeOfInformation.TAF, "EPGD"));
assertThat(StaticValuesForTest.URL_ADDRESS_FOR_CITY_PAIR_METAR).isEqualTo(xmlParser.createUrlAddress(TypeOfInformation.CITY_PAIR_METAR, "EPGD"));
assertThat(StaticValuesForTest.URL_ADDRESS_FOR_CITY_PAIR_TAF).isEqualTo(xmlParser.createUrlAddress(TypeOfInformation.CITY_PAIR_TAFS, "EPGD"));
}
Test passed, but its a little bit unreadable, I have to work with "clean code" I think.
EDIT:
#davidxxx please look at this:
public class UrlAddressService {
PageControllerForNearestCity pc = new PageControllerForNearestCity();
public String createUrlForMetar() {
String urlAddressForMetars = new StringBuilder()
.append(StaticValues.MAIN_URL_ADDRESS_FOR_CITY_PAIRS)
.append(pc.getDepartureAndArrivalTime().get("departureTime"))
.append(StaticValues.END_TIME_STRING)
.append(pc.getDepartureAndArrivalTime().get("arrivalTime"))
.append(StaticValues.STATION_STRING)
.append(pc.getOriginIcao())
.append(",")
.append(pc.getDestinationIcao())
.append(StaticValues.MOST_RECENT_FOR_TYPED_STATIONS_METARS)
.toString();
return urlAddressForMetars;
}
public String createUrlForTaf() {
String urlAddressForTafs = new StringBuilder()
.append(StaticValues.MAIN_URL_ADDRESS_FOR_CITY_PAIRS_TAFS)
.append(pc.getDepartureAndArrivalTime().get("departureTime"))
.append(StaticValues.END_TIME_STRING)
.append(pc.getDepartureAndArrivalTime().get("arrivalTime"))
.append(StaticValues.STATION_STRING)
.append(pc.getOriginIcao())
.append(",%20")
.append(pc.getDestinationIcao())
.append(StaticValues.MOST_RECENT_FOR_TYPED_STATIONS_TAFS)
.toString();
return urlAddressForTafs;
}
}
And createUrlAddress method:
public String createUrlAddress(TypeOfInformation typeOfInformation, String icao) {
switch (typeOfInformation) {
case METAR:
urlAddress = StaticValues.MAIN_URL_ADDRESS_FOR_METAR + icao;
break;
case TAF:
urlAddress = StaticValues.MAIN_URL_ADDRESS_FOR_TAF + icao + StaticValues.TAF_4_HOURS_BEFORE_NOW;
break;
case CITY_PAIR_METAR:
urlAddress = addressService.createUrlForMetar();
break;
case CITY_PAIR_TAFS:
urlAddress = addressService.createUrlForTaf();
break;
default:
System.out.println("Wrong Type of informations");
}
return urlAddress;
}
Do you think that it is better approach? I cannot reduce code during building a URL String, because there are 3 different parts of code for Tafs and Metars. Could you show me the best way how to test it if my test are bad?
I think you are in the right direction! You are mocking the dependencies of your code and that dependency is exactly the PageControllerForNearestCity!
One observation about the mock, you have to inject it on xmlParser, like this:
#Test
public void forGivenTypeOfInformationAndIcaoReturnUrl() {
// here you created the mock
PageControllerForNearestCity pcSpy = Mockito.spy(pc);
// I'll assume that xmlParser is the subject of your test
// and that you're injecting the mock like code below
xmlParser.setPageController(pcSpy);
// Configure the mock and then you do the assertion
assertThat(...)
}
PS I thought that the method has only one resposibility, just create a
string, am I wrong? Should it be divided into another one like a
"Service"?
Your method is good! It really do one thing and well and that is building an url from TypeOfInformation
My suggestion is that you refactor your code, after you write your test codes and make it pass! You can remove code duplication and make it more readable!
Remeber this:
'Any fool can write code that a computer can understand. Good
programmers write code that humans can understand.'
Martin Fowler
Good coding!
Edit
Some examples of your code with some refactoring
public String createUrlAddress(TypeOfInformation typeOfInformation, String icao) {
String urlAddress;
switch (typeOfInformation) {
case METAR:
urlAddress = StaticValues.MAIN_URL_ADDRESS_FOR_METAR + icao;
break;
case TAF:
urlAddress = StaticValues.MAIN_URL_ADDRESS_FOR_TAF + icao + StaticValues.TAF_4_HOURS_BEFORE_NOW;
break;
case CITY_PAIR_METAR:
// We delegate the build logic to pc because
// all the information needed to build the url
// is in the PageControllerForNearestCity class
urlAddress = pc.urlAddressForCityPairMetar();
break;
case CITY_PAIR_TAFS:
// Same
urlAddress = pc.urlAddressForCityPairTafs();
break;
default:
System.out.println("Wrong Type of informations");
}
return urlAddress;
}
class PageControllerForNearestCity {
public String urlAddressForCityPairMetar() {
return urlBasedOn(StaticValues.MAIN_URL_ADDRESS_FOR_CITY_PAIRSS, ",", StaticValues.MOST_RECENT_FOR_TYPED_STATIONS);
}
public String urlAddressForCityPairTafs() {
return urlBasedOn(StaticValues.MAIN_URL_ADDRESS_FOR_CITY_PAIRS_TAFS, ",%20", StaticValues.MOST_RECENT_FOR_TYPED_STATIONS_TAFS);
}
// This method removes the duplication that I mentioned before
private String urlBasedOn(String mainUrl, String separator, String endString) {
return mainUrl
+ this.getDepartureAndArrivalTime().get("departureTime")
+ StaticValues.END_TIME_STRING
+ this.getDepartureAndArrivalTime().get("arrivalTime")
+ StaticValues.STATION_STRING
+ this.getOriginIcao()
+ separator
+ this.getDestinationIcao()
+ endString;
}
}
Note that after this refactoring, your forGivenTypeOfInformationAndIcaoReturnUrl test method will become much simpler. But you will have to create test for urlAddressForCityPairMetar() and urlAddressForCityPairTafs().