post上传文件

//
//  ViewController.m
//  02-POST
//
//  Created by jerry on 15/10/9.
//  Copyright (c) 2015年 jerry. All rights reserved.
//

#import "ViewController.h"
#import "NSMutableURLRequest+Muitipart.h"
@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    [self postUpLoad];
}

- (void)postUpLoad
{
    // url
    NSURL *url = [NSURL URLWithString:@"http://127.0.0.1/post/upload.php"];

    NSMutableURLRequest *request = [NSMutableURLRequest requestWithUrl:url andLoaclFilePath:[[NSBundle mainBundle] pathForResource:@"111.png" ofType:nil] andFileName:@"123.png"];
    // connection
    [NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {
        // 反序列化的一个处理
        id result = [NSJSONSerialization JSONObjectWithData:data options:0 error:NULL];
        NSLog(@"%@",result);
    }];
}
@end

NSMutableURLRequest的分类：

.h

//
//  NSMutableURLRequest+Muitipart.h
//  02-POST
//
//  Created by jerry on 15/10/10.
//  Copyright (c) 2015年 jerry. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface NSMutableURLRequest (Muitipart)
/**
 *  类方法
 *
 *  @param url          要上传的服务器地址
 *  @param loadFilePath 要上传的文件全路径
 *  @param fileName     保存到服务器的名称。
 *
 */
+ (instancetype)requestWithUrl:(NSURL *)url andLoaclFilePath:(NSString *)loadFilePath andFileName:(NSString *)fileName;
@end

.m

//
//  NSMutableURLRequest+Muitipart.m
//  02-POST
//
//  Created by jerry on 15/10/10.
//  Copyright (c) 2015年 jerry. All rights reserved.
//

#import "NSMutableURLRequest+Muitipart.h"
static NSString *boundary = @"ZPUpLoad";
@implementation NSMutableURLRequest (Muitipart)
+ (instancetype)requestWithUrl:(NSURL *)url andLoaclFilePath:(NSString *)loadFilePath andFileName:(NSString *)fileName
{
    // request
#warning -- 这里不是NSURLRequest   而是   NSMutableURLRequest  因为这个请求是可变请求。
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:1 timeoutInterval:2.0f];
    // 声明是哪种格式的请求，默认是GET。
    request.HTTPMethod = @"POST";
    /**
     \r\n--(可以随便写, 但是不能有中文)\r\n
     Content-Disposition: form-data; name="userfile(php脚本中用来读取文件的字段)"; filename="demo.json(要保存到服务器的文件名)"\r\n
     Content-Type: application/octet-stream(上传文件的类型)\r\n\r\n
     \r\n--(可以随便写, 但是不能有中文)\r\n

     */
    // 数据体  拼接数据体
    NSMutableData *dataM = [NSMutableData data];
    // 1. \r\n--(可以随便写, 但是不能有中文)\r\n
    NSString *str = [NSString stringWithFormat:@"\r\n--%@\r\n",boundary];
    [dataM appendData:[str dataUsingEncoding:NSUTF8StringEncoding]];

    // 2. Content-Disposition: form-data; name="userfile(php脚本中用来读取文件的字段)"; filename="demo.json(要保存到服务器的文件名)"\r\n
    str = [NSString stringWithFormat:@"Content-Disposition: form-data; name=\"userfile\"; filename=\"%@\" \r\n", fileName];

    [dataM appendData:[str dataUsingEncoding:NSUTF8StringEncoding]];

    // 3.Content-Type: application/octet-stream(上传文件的类型)\r\n\r\n
    str = @"Content-Type: application/octet-stream\r\n\r\n";
    [dataM appendData:[str dataUsingEncoding:NSUTF8StringEncoding]];

    // 4.要上传文件的二进制流

    [dataM appendData:[NSData dataWithContentsOfFile:loadFilePath]];

    // 5.\r\n--(可以随便写, 但是不能有中文)\r\n
    str = [NSString stringWithFormat:@"\r\n--%@--\r\n",boundary];
    [dataM appendData:[str dataUsingEncoding:NSUTF8StringEncoding]];

    request.HTTPBody = dataM;

    /**
     Content-Length(文件的大小)    290
     Content-Type    multipart/form-data; boundary(分隔符)=(可以随便写, 但是不能有中文)
     */

    // 设置请求头
    NSString *headerStr = [NSString stringWithFormat:@"multipart/form-data; boundary=%@",boundary];
    [request setValue:headerStr forHTTPHeaderField:@"Content-Type"];
    return request;
}
@end