iOS通过Http 上传图片

- (NSMutableURLRequest )PostImageRequest:(NSString )URLString
                                  UIImage:(UIImage)image
                               parameters:(NSDictionary )parameters
                                  success:(void (^)(id))success
                                  failure:(void (^)(NSError ))failure
{
    _success = [success copy];
    _failure = [failure copy];
    //分界线的标识符
    NSString TWITTERFON_FORM_BOUNDARY = @"AaB03x";
    //根据url初始化request
    _request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:URLString]
                                                           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];
    //得到图片的data
    NSData data = UIImageJPEGRepresentation(image, 1);
    //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= [parameters 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",[parameters 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=\"ImageField\"; filename=\"x1234.png\"\r\n"];
//声明上传文件的格式
[body appendFormat:@"Content-Type: image/jpeg\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"];

return _request;

}</pre>