网络请求数据（同步POST，异步POST）

//同步POST

-(void)synPost{
    //获取URL接口，不含参数
    NSString *str = @"http://www.haninfo.cc:2060/Login/LoginData.asmx/Login";
    //转码---拼接方法，为避免参数是汉字时，打印结果不显示汉字
    str = [str stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
    NSURL *url = [NSURL URLWithString:str];
   
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:0 timeoutInterval:10];
   
    //post方式的参数封装
    NSString *dataStr = [NSString stringWithFormat:@"sLogin=%@&sVerifyCode=%@&sPadId=%@",@"yyj",@"",@""];
    //将参数列表转换成data
    NSData *data = [dataStr dataUsingEncoding:NSUTF8StringEncoding];
    //设置参数体
    [request setHTTPBody:data];
    //设置请求方式
    [request setHTTPMethod:@"POST"];
   
    //发送请求
    NSData *responData = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
    //解析
    id obj = [NSJSONSerialization JSONObjectWithData:responData options:NSJSONReadingAllowFragments error:nil];
    NSLog(@"%@",obj);

}

=====================================================

//异步POST

-(void)asynPOST{
    NSString *str = @"http://www.haninfo.cc:2060/Login/LoginData.asmx/Login";
   
    str = [str stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];//把汉字转换成字符串
    NSURL *url = [NSURL URLWithString:str];
   
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:0 timeoutInterval:10];
   
    //post方式的参数封装
    NSString *dataStr = [NSString stringWithFormat:@"sLogin=%@&sVerifyCode=%@&sPadId=%@",@"yyj",@"",@""];
    //将参数列表转换成data
    NSData *data = [dataStr dataUsingEncoding:NSUTF8StringEncoding];
    //设置参数体
    [request setHTTPBody:data];
    //设置请求方式
    [request setHTTPMethod:@"POST"];

//方法一：系统封装好的（不在需要代理方法）

[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {
        NSDictionary *dic = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments error:nil];
        NSLog(@"%@",dic);
    }];

//方法二：需要代理方法

[NSURLConnection connectionWithRequest:request delegate:self];
}

-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response{
    _muData = [NSMutableData data];
}

-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{
   
    [_muData appendData:data];
}

-(void)connectionDidFinishLoading:(NSURLConnection *)connection{
//解析
}

-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error{
    //连接服务器失败
    NSLog(@"错误信息：%@",error);
}