在ObjectiveC中从NSDictionary对象创建URL查询参数

在Objective-C中，从NSDictionary对象创建URL查询参数可以通过以下步骤实现：

1. 导入Foundation框架#import<Foundation/Foundation.h>
2. 创建一个NSDictionary对象，包含要作为URL查询参数的键值对NSDictionary *params = @{ @"key1": @"value1", @"key2": @"value2", @"key3": @"value3" };
3. 使用NSCharacterSet对象创建一个URL查询参数字符串NSString *query = [self queryStringFromParameters:params];
4. 将查询参数字符串附加到URL上NSURL *url = [NSURL URLWithString:@"https://example.com"]; NSURL *urlWithQuery = [NSURL URLWithString:[url absoluteString] relativeToURL:url];
5. 完整的代码如下：#import<Foundation/Foundation.h> @interface NSDictionary (URLQuery) - (NSString *)queryString; @end @implementation NSDictionary (URLQuery) - (NSString *)queryString { NSMutableArray *parts = [NSMutableArray array]; [self enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) { NSString *part = [NSString stringWithFormat:@"%@=%@", [key stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet URLQueryAllowedCharacterSet]], [obj stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet URLQueryAllowedCharacterSet]]]; [parts addObject:part]; }]; return [parts componentsJoinedByString:@"&"]; } @end int main(int argc, const char * argv[]) { @autoreleasepool { NSDictionary *params = @{ @"key1": @"value1", @"key2": @"value2", @"key3": @"value3" }; NSURL *url = [NSURL URLWithString:@"https://example.com"]; NSURL *urlWithQuery = [NSURL URLWithString:[url absoluteString] relativeToURL:url]; NSString *query = [params queryString]; NSURL *finalURL = [NSURL URLWithString:[NSString stringWithFormat:@"%@?%@", [urlWithQuery absoluteString], query]]; NSLog(@"%@", finalURL); } return 0; }

这段代码将创建一个包含查询参数的URL，例如：https://example.com?key1=value1&key2=value2&key3=value3。