http请求带json格式不能请求数据

在做请求http时，后面的参数格式为json字符串，请求后，服务端无响应，且无数据返回,不报异常。当换成其它带参http时，可以正常返回数据。开始以为是末转义参数中的大括号，后来把大括号替换为中括号就正常了，不知为何要这样处理？

代码如下：

#define REQUEST_URL @"http://127.0.0.1:9091/?param={%22className%22:%22AppServiceImpl%22,%22methodName%22:%22doSelect%22,%22parameter%22:%22test%22}"

- (IBAction)requestHttpBtn:(id)sender {
    NSString *jsonStr = [REQUEST_URL stringByReplacingOccurrencesOfString:@"{" withString:@"]"];
    [jsonStr stringByReplacingOccurrencesOfString:@"}" withString:@"]"];
    NSURL *url = [NSURL URLWithString:jsonStr];
    NSMutableURLRequest *request = [NSMutableURLRequest new];
    [request setURL:url];
    [request setHTTPMethod:@"POST"];
//    [request addValue:@"text/json" forHTTPHeaderField:@"Content-Type"];
//    [request setValue:@"test" forHTTPHeaderField:@"User-Agent"];
    NSHTTPURLResponse *response;
    NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:nil];
    NSLog(@"data : %@",[data description]);
    NSString *result = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
    //showTxt.text = result;
    NSLog(@"Result : %@",result);
}

今天完善http通过json格式参数通信例子，昨天的问题已解决，其实不需要替换大括号的，对请求的url进行转码就可以了。如下代码：

NSMutableDictionary *dictionary = [[NSMutableDictionary alloc] init];
//想通过对象直接转为json，暂时还没解决方案
 //        LoginResquest *loginResquest = [[LoginResquest alloc] init];
//        [loginResquest setClassName:@"AppServiceImpl"];
//        [loginResquest setMethodName:@"methodName"];
//        [loginResquest setPassword:password];
//        [loginResquest setUserName:userName];
//        [dictionary setValue:loginResquest forKey:@"LoginResquest"];
        [dictionary setValue:@"AppServiceImpl" forKey:@"className"];
        [dictionary setValue:@"doSave" forKey:@"methodName"];
        NSMutableDictionary *loginDic = [[NSMutableDictionary alloc] init];
        [loginDic setValue:password forKey:@"password"];
        [loginDic setValue:userName forKey:@"userName"];;
        [dictionary setValue:loginDic forKey:@"LoginRequest"];
        NSMutableString *urlStr = [[NSMutableString alloc] initWithString:REQUEST_URL];
        NSString *aStr = [dictionary JSONRepresentation];
        //以下为url进行转码
        aStr = [aStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];//NSASCIIStringEncoding
        [urlStr appendString:aStr];
        NSURL *url = [NSURL URLWithString:urlStr];
        NSMutableURLRequest *request = [NSMutableURLRequest new];
        [request setURL:url];
        [request setHTTPMethod:@"POST"];
        NSHTTPURLResponse *response;
        NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:nil];
        NSString *result = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
        NSLog(@"Result : %@",result);

ss