Creating URL query parameters from NSDictionary objects in ObjectiveC

//
//  Http.m
//  test
//
//  Created by robin on 14-4-4.
//  Copyright (c) 2014年 robin. All rights reserved.
//

#import "Http.h"

@implementation Http
//  参数URL加密
+(NSString*)urlEscape:(NSString *)unencodedString {
    NSString *s = (NSString *)CFBridgingRelease(CFURLCreateStringByAddingPercentEscapes(NULL,
                                                                                        (CFStringRef)unencodedString,
                                                                                        NULL,
                                                                                        (CFStringRef)@"!*'\"();:@&=+$,/?%#[]% ",
                                                                                        kCFStringEncodingUTF8));
    return s;
}

// 把参数放到URL尾部
+(NSString*)addQueryStringToUrl:(NSString *)url params:(NSDictionary *)params {
    NSMutableString *urlWithQuerystring = [[NSMutableString alloc] initWithString:url];
    // 转换参数
    if (params) {
        for(id key in params) {
            NSString *sKey = [key description];
            NSString *sVal = [[params objectForKey:key] description];
            // 需要添加 add ?k=v or &k=v ?
            if ([urlWithQuerystring rangeOfString:@"?"].location == NSNotFound) {
                [urlWithQuerystring appendFormat:@"?%@=%@", [Http urlEscape:sKey], [Http urlEscape:sVal]];
            } else {
                [urlWithQuerystring appendFormat:@"&%@=%@", [Http urlEscape:sKey], [Http urlEscape:sVal]];
            }
        }
    }
    return urlWithQuerystring;
}

@end

For Example:

NSDictionary *params = @{@"params1":@"params", @"params2":@"paramswww"}; 

NSString *urlWithQuerystring = [self addQueryStringToUrl:@"https://www.baidu.com/login" params:params];