一： 封装的好处

      1.1 可以降低网络请求方法与Controller(控制器)的耦合度,即使网络使用的第三方框架发生不兼容、错误等问题从而想换框架时，也不用到每个控制器里面改代码(50、60页面会改到想哭)。 
      1.2 建立独立的工具类，方便管理。 
      1.3 优化代码结构。

二：导入AFNetworking

导入AFNetworking有两种方法： 一种直接将AFNetworking文件拖入项目； 另一种使用CocoaPods导入。

三：创建封装类

创建FBYHomeService类继承NSObject .h代码

   //
   // FBYHomeService.h
   // agreePay
   //
   // Created by fbyon 2017/4/24.
   // Copyright © 2017年 agreePay. All rights reserved.
   //

   #import <Foundation>

   @interface FBYHomeService : NSObject

   //pageNum和action标记参数，可以区分接口类型等
   //Alldic为网络请求报文//url接口地址
   //success获取接口成功返回参数
   //failure网络请求失败错误信息
  - (void)searchMessage:(NSString *)pageNum andWithAction:(NSString *)action andWithDic:(NSDictionary *)Alldic andUrl:(NSString *)url andSuccess:(void(^)(NSDictionary *dic))success andFailure:(void(^)(int fail))failure;

   @end

.m代码

   //
   // FBYHomeService.m
   // agreePay
   //
   // Created by 范保莹 on 2017/4/24.
   // Copyright © 2017年 agreePay. All rights reserved.
   //

   #import "FBYHomeService.h"
   #import "AFNetworking.h"

  @implementation FBYHomeService
  - (void)searchMessage:(NSString *)pageNum andWithAction:(NSString *)action andWithDic:(NSDictionary *)Alldic andUrl:(NSString *)url andSuccess:(void (^)(NSDictionary *))success andFailure:(void (^)(int))failure{
     //1.创建ADHTTPSESSIONMANGER对象      
     AFHTTPSessionManager *manager=[AFHTTPSessionManager manager]; 
     //2.设置该对象返回类型
     [manager.requestSerializer setValue:@"application/json; charset=utf-8" forHTTPHeaderField:@"Content-Type"];

     if ([pageNum isEqualToString:[NSString stringWithFormat:@"get"]]) {
          NSString *urlstr= [NSString stringWithFormat:@"%@%@",AGREEHanBingURL,url]; 
          NSLog(@"%@",urlstr); 
          //调出请求头 
          manager.requestSerializer = [AFJSONRequestSerializer serializer]; 
          //将token封装入请求头
          NSUserDefaults *tokenid = [NSUserDefaults standardUserDefaults];
          NSString *token = [tokenid objectForKey:@"tokenid"]; 
          NSLog(@"%@",token);

          [manager.requestSerializer setValue:token forHTTPHeaderField:@"token"]; 

          [manager GET:urlstr parameters:nil progress:nil success:^(NSURLSessionDataTask * _Nonnull task, id _Nullable responseObject) { 
          NSDictionary *dic = responseObject; success(dic); } failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {

      }]; 

}else { 
        NSString *urlstr= [NSString stringWithFormat:@"%@%@",AGREENewFuWuURL,url];  
        NSLog(@"%@",urlstr); 
        [manager.requestSerializer setValue:@"1" forHTTPHeaderField:@"x-signature"];

        [manager.requestSerializer setValue:@"2" forHTTPHeaderField:@"x-timestamp"]; 
        manager.requestSerializer = [AFJSONRequestSerializer serializer]; 
        manager.responseSerializer = [AFJSONResponseSerializer serializer];
        [manager POST:urlstr parameters:Alldic progress:nil success:^(NSURLSessionDataTask * _Nonnull task, id _Nullable responseObject) { 
        NSDictionary *dic = responseObject;
        success(dic); 
   }failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
          failure(404);
          }];
   }
}
@end

四：封装类的使用

LoginViewController.m中代码 首先引入头文件

  #import "AFNetworking.h"
  #import "FBYHomeService.h"

使用代码

   NSMutableDictionary *mutdic=[NSMutableDictionary dictionaryWithCapacity:0]; 
   mutdic[@"userName"] = @"admin"; 
   mutdic[@"password"] = @"admin";       

   //网络请求
   FBYHomeService *service1 = [[FBYHomeService alloc]init]; [service1 searchMessage:@"post" andWithAction:nil andWithDic:mutdic andUrl:MerchantLogin andSuccess:^(NSDictionary *dic) {   
        NSLog(@"%@",dic);

        NSString *str = [dic objectForKey:@"code"]; 
        int intString = [str intValue]; 

        if (intString == 0) {
            NSString *token = [dic objectForKey:@"token"]; 

            NSLog(@"%@",token); 
            NSUserDefaults *tokenid = [NSUserDefaults standardUserDefaults];
            [tokenid setObject:token forKey:@"tokenid"];
            [tokenid synchronize]; 
    }else{ 
            UIAlertController *alert = [UIAlertCon  troller alertControllerWithTitle:@"提示" message:[dic objectForKey:@"msg"] preferredStyle:UIAlertControllerStyleAlert]; 

            UIAlertAction *action1 = [UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) { 

    }]; 
             [alert addAction:action1]; 
             [self presentViewController:alert animated:YES completion:nil];
  } 
} andFailure:^(int fail) {

}];