解析 URL 字符串以获取键值的最佳方法？

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最佳答案

edit (June 2018): this answer is better. Apple added NSURLComponents in iOS 7.

I would create a dictionary, get an array of the key/value pairs with

NSMutableDictionary *queryStringDictionary = [[NSMutableDictionary alloc] init];
NSArray *urlComponents = [urlString componentsSeparatedByString:@"&"];

Then populate the dictionary :

for (NSString *keyValuePair in urlComponents)
{
NSArray *pairComponents = [keyValuePair componentsSeparatedByString:@"="];
NSString *key = [[pairComponents firstObject] stringByRemovingPercentEncoding];
NSString *value = [[pairComponents lastObject] stringByRemovingPercentEncoding];


[queryStringDictionary setObject:value forKey:key];
}

You can then query with

[queryStringDictionary objectForKey:@"ad_eurl"];

This is untested, and you should probably do some more error tests.

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-(NSArray *)getDataOfQueryString:(NSString *)url{
NSArray *strURLParse = [url componentsSeparatedByString:@"?"];
NSMutableArray *arrQueryStringData = [[NSMutableArray alloc] init];
if ([strURLParse count] < 2) {
return arrQueryStringData;
}
NSArray *arrQueryString = [[strURLParse objectAtIndex:1] componentsSeparatedByString:@"&"];


for (int i=0; i < [arrQueryString count]; i++) {
NSMutableDictionary *dicQueryStringElement = [[NSMutableDictionary alloc]init];
NSArray *arrElement = [[arrQueryString objectAtIndex:i] componentsSeparatedByString:@"="];
if ([arrElement count] == 2) {
[dicQueryStringElement setObject:[arrElement objectAtIndex:1] forKey:[arrElement objectAtIndex:0]];
}
[arrQueryStringData addObject:dicQueryStringElement];
}


return arrQueryStringData;
}

You this function just Pass URL and you will get all the element of querystring.

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I'm a bit late, but the answers provided until now didn't work as I needed to. You can use this code snippet:

NSMutableDictionary *queryStrings = [[NSMutableDictionary alloc] init];
for (NSString *qs in [url.query componentsSeparatedByString:@"&"]) {
// Get the parameter name
NSString *key = [[qs componentsSeparatedByString:@"="] objectAtIndex:0];
// Get the parameter value
NSString *value = [[qs componentsSeparatedByString:@"="] objectAtIndex:1];
value = [value stringByReplacingOccurrencesOfString:@"+" withString:@" "];
value = [value stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];


queryStrings[key] = value;
}

Where url is the URL you want to parse. You have all of the query strings, escaped, in the queryStrings mutable dictionary.

EDIT: Swift version:

var queryStrings = [String: String]()
if let query = url.query {
for qs in query.componentsSeparatedByString("&") {
// Get the parameter name
let key = qs.componentsSeparatedByString("=")[0]
// Get the parameter value
var value = qs.componentsSeparatedByString("=")[1]
value = value.stringByReplacingOccurrencesOfString("+", withString: " ")
value = value.stringByReplacingPercentEscapesUsingEncoding(NSUTF8StringEncoding)!


queryStrings[key] = value
}
}

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This code is work in three cases

1.http://www.youtube.com/watch?v=VWsl7C-y7EI&feature=youtu.be 2.http://youtu.be/lOvcFqQyaDY
3.http://www.youtube.com/watch?v=VWsl7C-y7EI

NSArray *arr = [youtubeurl componentsSeparatedByString:@"v="];
NSString *youtubeID;
if([arr count]>0)
{
if([arr count]==1){
youtubeID= [[youtubeurl componentsSeparatedByString:@"/"] lastObject];


}
else{
NSArray *urlComponents = [[arr objectAtIndex:1] componentsSeparatedByString:@"&"];
youtubeID=[urlComponents objectAtIndex:0];
}
}

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Query property in the NSURL will give the query string. Then you can parse the query string using componentsSeparatedByString

    NSArray *parameters = [[url query] componentsSeparatedByString:@"&"];


NSMutableDictionary *keyValuePairs = [NSMutableDictionary dictionary];


for (NSString *eachParam in parameters)
{
NSArray *QryParts = [eachParam componentsSeparatedByString:@"="];
if ( [QryParts count] == 2 )
{
keyValuePairs[QryParts[0]] = QryParts[1];
}
else
{
keyValuePairs[QryParts[0]] = QryParts[0];
}
}


NSString * name = [keyValuePairs valueForKey:@"name"];
NSString * username = [keyValuePairs valueForKey:@"username"];

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I also answered this at https://stackoverflow.com/a/26406478/215748.

You can use queryItems in URLComponents.

When you get this property’s value, the NSURLComponents class parses the query string and returns an array of NSURLQueryItem objects, each of which represents a single key-value pair, in the order in which they appear in the original query string.

let url = "http://example.com?param1=value1&param2=param2"
let queryItems = URLComponents(string: url)?.queryItems
let param1 = queryItems?.filter({$0.name == "param1"}).first
print(param1?.value)

Alternatively, you can add an extension on URL to make things easier.

extension URL {
var queryParameters: QueryParameters { return QueryParameters(url: self) }
}


class QueryParameters {
let queryItems: [URLQueryItem]
init(url: URL?) {
queryItems = URLComponents(string: url?.absoluteString ?? "")?.queryItems ?? []
print(queryItems)
}
subscript(name: String) -> String? {
return queryItems.first(where: { $0.name == name })?.value
}
}

You can then access the parameter by its name.

let url = URL(string: "http://example.com?param1=value1&param2=param2")!
print(url.queryParameters["param1"])

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If you want to do the same thing in swift, you can use an extension.

extension NSURL {
func queryDictionary() -> [String:String] {
let components = self.query?.componentsSeparatedByString("&")
var dictionary = [String:String]()


for pairs in components ?? [] {
let pair = pairs.componentsSeparatedByString("=")
if pair.count == 2 {
dictionary[pair[0]] = pair[1]
}
}


return dictionary
}
}

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If you're using NSURLComponents the following concise extension will also do the trick:

extension NSURLComponents {


func getQueryStringParameter(name: String) -> String? {
return (self.queryItems? as [NSURLQueryItem])
.filter({ (item) in item.name == name }).first?
.value()
}


}

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For iOS8 and above using NSURLComponents :

+(NSDictionary<NSString *, NSString *> *)queryParametersFromURL:(NSURL *)url {
NSURLComponents *urlComponents = [NSURLComponents componentsWithURL:url resolvingAgainstBaseURL:NO];
NSMutableDictionary<NSString *, NSString *> *queryParams = [NSMutableDictionary<NSString *, NSString *> new];
for (NSURLQueryItem *queryItem in [urlComponents queryItems]) {
if (queryItem.value == nil) {
continue;
}
[queryParams setObject:queryItem.value forKey:queryItem.name];
}
return queryParams;
}

For iOS 8 below:

+(NSDictionary<NSString *, NSString *> *)queryParametersFromURL:(NSURL *)url
NSMutableDictionary<NSString *, NSString *> * parameters = [NSMutableDictionary<NSString *, NSString *> new];
[self enumerateKeyValuePairsFromQueryString:url.query completionblock:^(NSString *key, NSString *value) {
parameters[key] = value;
}];
return parameters.copy;
}


- (void)enumerateKeyValuePairsFromQueryString:(NSString *)queryString completionBlock:(void (^) (NSString *key, NSString *value))block {
if (queryString.length == 0) {
return;
}
NSArray *keyValuePairs = [queryString componentsSeparatedByString:@"&"];
for (NSString *pair in keyValuePairs) {
NSRange range = [pair rangeOfString:@"="];
NSString *key = nil;
NSString *value = nil;


if (range.location == NSNotFound) {
key = pair;
value = @"";
}
else {
key = [pair substringToIndex:range.location];
value = [pair substringFromIndex:(range.location + range.length)];
}


key = [self decodedStringFromString:key];
key = key ?: @"";


value = [self decodedStringFromString:value];
value = value ?: @"";


block(key, value);
}
}


+ (NSString *)decodedStringFromString:(NSString *)string {
NSString *input = shouldDecodePlusSymbols ? [string stringByReplacingOccurrencesOfString:@"+" withString:@" " options:NSLiteralSearch range:NSMakeRange(0, string.length)] : string;
return [input stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
}

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- (NSString *)getLoginTokenFromUrl:(NSString *)urlString {
NSURL *url = [NSURL URLWithString:urlString];
NSArray *queryStrings = [url.query componentsSeparatedByString:@"&"];


NSMutableDictionary *queryParams = [[NSMutableDictionary alloc] init];
for (NSString *qs in queryStrings) {
// Get the parameter name
NSArray *components = [qs componentsSeparatedByString:@"="];
NSString *key = [components objectAtIndex:0];


// Get the parameter value
NSString *value;
if (components.count > 1) {
value = [components objectAtIndex:1];
}
else {
value = @"";
}
value = [value stringByReplacingOccurrencesOfString:@"+" withString:@" "];
value = [value stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];


queryParams[key] = value;
}


return [queryParams objectForKey:@"login_token"];
}

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A Swift 2 approach:

extension NSURL {


var queryDictionary: [String: String] {
var queryDictionary = [String: String]()
guard let components = NSURLComponents(URL: self, resolvingAgainstBaseURL: false), queryItems = components.queryItems else { return queryDictionary }
queryItems.forEach { queryDictionary[$0.name] = $0.value }
return queryDictionary
}


}

Download Gist

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As full function:

+ (NSString *)getQueryComponentWithName:(NSString *)name  fromURL:(NSURL *)url{


NSString *component = nil;
if (url) {
NSString *query = url.query;


NSMutableDictionary *queryStringDictionary = [NSMutableDictionary dictionary];
NSArray *urlComponents = [query componentsSeparatedByString:@"&"];


for (NSString *keyValuePair in urlComponents){


NSArray *pairComponents = [keyValuePair componentsSeparatedByString:@"="];
NSString *key = [[pairComponents firstObject] stringByRemovingPercentEncoding];
NSString *value = [[pairComponents lastObject] stringByRemovingPercentEncoding];


[queryStringDictionary setObject:value forKey:key];
}


component = [queryStringDictionary objectForKey:name];
}


return component;
}
[self getQueryComponentWithName:@"example" fromURL:[NSURL URLWithString:@"https://google.es/?example=test"]];

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Since iOS 8 you can directly use properties name and value on NSURLQueryItem.

Example, how to parse URL and get specific values for a key in parsed pairs.

NSURLComponents *urlComponents = [NSURLComponents componentsWithURL:@"someURL" resolvingAgainstBaseURL:false];
NSArray *queryItems = urlComponents.queryItems;
NSMutableArray *someIDs = [NSMutableArray new];
for (NSURLQueryItem *item in queryItems) {
if ([item.name isEqualToString:@"someKey"]) {
[someIDs addObject:item.value];
}
}
NSLog(@"%@", someIDs);

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A late solution to this in the form of a Swift 3 extension on URL

extension URL {


func value(for paramater: String) -> String? {


let queryItems = URLComponents(string: self.absoluteString)?.queryItems
let queryItem = queryItems?.filter({$0.name == paramater}).first
let value = queryItem?.value


return value
}


}

gist

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To get query parameters as a dict:

extension URL {
var parameters: [String: String] {
var parameters = [String: String]()
if let urlComponents = URLComponents(url: self, resolvingAgainstBaseURL: false),
let queryItems = urlComponents.queryItems {
for queryItem in queryItems where queryItem.value != nil {
parameters[queryItem.name] = queryItem.value
}
}
return parameters
}
}

or return Optional if this more convenient in your case.

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Swift 5

extension URL {
func queryParams() -> [String:String] {
let queryItems = URLComponents(url: self, resolvingAgainstBaseURL: false)?.queryItems
let queryTuples: [(String, String)] = queryItems?.compactMap{
guard let value = $0.value else { return nil }
return ($0.name, value)
} ?? []
return Dictionary(uniqueKeysWithValues: queryTuples)
}
}