// 1、创建请求

    NSURL *url = [NSURL URLWithString:@"http://120.25.226.186:32812/upload"];

    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy: timeoutInterval:2.0f];

    // 2、设置请求头（告诉服务器这是一个文件上传的请求）

    [request setValue:[NSString stringWithFormat:@"multipart/form-data; boundary=%@",XMGEncode(@"520it")] forHTTPHeaderField:@"Content-Type"];

    // 3、设置请求体

    // 开始标记

    NSMutableData *body = [NSMutableData data];

    [body appendData:XMGEncode(@"--")];

    [body appendData:XMGEncode(@"520it")];

    [body appendData:XMGNewLine];

    // 文件参数

    // 参数名和文件名

    [body appendData:XMGEncode([NSString stringWithFormat:@"Content-Disposition: form-data; name=\"file\"; filename=\"test.png\""])];

    [body appendData:XMGNewLine];

    // 文件类型

    [body appendData:XMGEncode([NSString stringWithFormat:@"Content-Type: image/png"])];

    [body appendData:XMGNewLine];

    // 文件数据

    [body appendData:XMGNewLine];

    UIImage *img = [UIImage imageNamed:@""];

    [body appendData:UIImagePNGRepresentation(img)];

    [body appendData:XMGNewLine];

    // 非文件参数

    [body appendData:XMGEncode(@"--")];

    [body appendData:XMGEncode(@"520it")];

    [body appendData:XMGNewLine];

    // 参数名

    [body appendData:XMGEncode([NSString stringWithFormat:@"Content-Disposition: form-data; name=\"username\""])];

    [body appendData:XMGNewLine];

    // 参数值

    [body appendData:XMGNewLine];

    [body appendData:XMGEncode(@"jack")];

    [body appendData:XMGNewLine];

    // 结束标记

    [body appendData:XMGEncode(@"--")];

    [body appendData:XMGEncode(@"520it")];

    [body appendData:XMGEncode(@"--")];

    [body appendData:XMGNewLine];

    request.HTTPBody = body;

    // 4、链接服务器发送请求

    [NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse * _Nullable response, NSData * _Nullable data, NSError * _Nullable connectionError) {

        NSLog(@"%@", [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil]);

    }];

AFHTTPSessionManager *manager = [AFHTTPSessionManager manager];

    [manager POST:@"http://120.25.226.186:32812/upload" parameters:@{@"username" : @"jack"} constructingBodyWithBlock:^(id<AFMultipartFormData>  _Nonnull formData) {

        // 在这个block中设置需要上传的文件

        //            NSData *data = [NSData dataWithContentsOfFile:@"/Users/xiaomage/Desktop/placeholder.png"];

        //            [formData appendPartWithFileData:data name:@"file" fileName:@"test.png" mimeType:@"image/png"];

        //            [formData appendPartWithFileURL:[NSURL fileURLWithPath:@"/Users/xiaomage/Desktop/placeholder.png"] name:@"file" fileName:@"xxx.png" mimeType:@"image/png" error:nil];

        [formData appendPartWithFileURL:[NSURL fileURLWithPath:@"/Users/xiaomage/Desktop/placeholder.png"] name:@"file" error:nil];

    } progress:^(NSProgress * _Nonnull uploadProgress) {

        //

    } success:^(NSURLSessionDataTask * _Nonnull task, id  _Nullable responseObject) {

        //

    } failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {

        //

    }];