IOS(http几种请求)

ios有几种请求比如最常用的post，get等。get的参数会在URL地址里看到，假如存在用户名和密码会被大家看到这就非常不安全。这是可以选择post的方式。虽然他们都可以放一些请求参数。请求可能要设置一些参数什么的，以下举个例子是发送图片的。其他一些delete，put请求都是类似的。网上也有一些开源的类库是封装了一些网络请求的。比如asihttp这个类库封装的一些和网络交互的方便的请求。缺点是用别人的类库一旦别人升级改动你也得自己跟着改。

//分界线的标识符
        NSString *TWITTERFON_FORM_BOUNDARY = @"AaB03x";
        //根据url初始化request
        NSMutableURLRequest* request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:url]
                                                               cachePolicy:NSURLRequestReloadIgnoringLocalCacheData
                                                           timeoutInterval:10];
        //分界线 --AaB03x
        NSString *MPboundary=[[NSString alloc]initWithFormat:@"--%@",TWITTERFON_FORM_BOUNDARY];
        //结束符 AaB03x--
        NSString *endMPboundary=[[NSString alloc]initWithFormat:@"%@--",MPboundary];
        //要上传的图片
        UIImage *image=[params objectForKey:@"pic"];
        //得到图片的data
        NSData* data = UIImagePNGRepresentation(image);
        //http body的字符串
        NSMutableString *body=[[NSMutableString alloc]init];
        //参数的集合的所有key的集合
        NSArray *keys= [params allKeys];
        
        //遍历keys
        for(int i=0;i<[keys count];i++)
        {
            //得到当前key
            NSString *key=[keys objectAtIndex:i];
            //如果key不是pic，说明value是字符类型，比如name：Boris
            if(![key isEqualToString:@"pic"])
            {
                //添加分界线，换行
                [body appendFormat:@"%@\r\n",MPboundary];
                //添加字段名称，换2行
                [body appendFormat:@"Content-Disposition: form-data; name=\"%@\"\r\n\r\n",key];
                //添加字段的值
                [body appendFormat:@"%@\r\n",[params objectForKey:key]];           
            }
        }
        
        ////添加分界线，换行
        [body appendFormat:@"%@\r\n",MPboundary];
        //声明pic字段，文件名为boris.png
        [body appendFormat:@"Content-Disposition: form-data; name=\"pic\"; filename=\"boris.png\"\r\n"];
        //声明上传文件的格式
        [body appendFormat:@"Content-Type: image/png\r\n\r\n"];
        
        //声明结束符：--AaB03x--
        NSString *end=[[NSString alloc]initWithFormat:@"\r\n%@",endMPboundary];
        //声明myRequestData，用来放入http body
        NSMutableData *myRequestData=[NSMutableData data];
        //将body字符串转化为UTF8格式的二进制
        [myRequestData appendData:[body dataUsingEncoding:NSUTF8StringEncoding]];
        //将image的data加入
        [myRequestData appendData:data];
        //加入结束符--AaB03x--
        [myRequestData appendData:[end dataUsingEncoding:NSUTF8StringEncoding]];
        
        //设置HTTPHeader中Content-Type的值
        NSString *content=[[NSString alloc]initWithFormat:@"multipart/form-data; boundary=%@",TWITTERFON_FORM_BOUNDARY];
        //设置HTTPHeader
        [request setValue:content forHTTPHeaderField:@"Content-Type"];
        //设置Content-Length
        [request setValue:[NSString stringWithFormat:@"%d", [myRequestData length]] forHTTPHeaderField:@"Content-Length"];
        //设置http body
        [request setHTTPBody:myRequestData];
        //http method
        [request setHTTPMethod:@"POST"]; 
        
        //建立连接，设置代理
        NSURLConnection *conn = [[NSURLConnection alloc] initWithRequest:request delegate:self];
        
        //设置接受resp*****e的data
        if (conn) {
            mResp*****eData = [[NSMutableData data] retain];
        }