iOS中NSURLConnection、NSURLSession 常用请求(GET、POST)方法总结

GET和POST的区别：

• 1.GET方法: 参数添加到url的后面。参数与地址用？拼接，参数与参数之间用&。

  POST方法：把参数添加到请求体里面。不会拼接到url后面。

• 2.GET会带来安全问题。
• 3.GET请求参数有大小（2K-8K）限制。而POST请求没有大小限制。所以所有的文件上传都会用POST请求。

NSURLConnection在目前版本中已被放弃，当前也可用，但 建议用NSURLSession，还有很多以前的项目用的是NSURLConnection，所以遇到时要知道。

1. NSURLConnection

• 1.发送GET请求

  //1、获取url
  NSString *urlString = [NSString stringWithFormat:@"http://www.baidu.com/api/category/custom?user_id=%d&city_id=%d&page_no=%d&page_size=%d",1000,1,1,20];
  NSURL *url = [NSURL URLWithString:urlString];
  
  //2、创建请求对象
  NSURLRequest *request = [NSURLRequest requestWithURL:url];
  
  //3、请求数据
  [NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse * _Nullable response, NSData * _Nullable data, NSError * _Nullable connectionError) {
  
      NSLog(@"%@",[[NSString alloc] initWithData:data encoding:4]);
  }];
             

• 2.发送POST请求

  //1、获取url
      NSString *urlString = @"http://www.baidu.com/api/category/custom";
      NSURL *url = [NSURL URLWithString:urlString];
  
      //2、创建请求对象
      NSMutableURLRequest *mutableRequest = [NSMutableURLRequest requestWithURL:url];
  
      //3、设置请求类型、请求体
      //默认HTTPMethod = @"GET";
      mutableRequest.HTTPMethod = @"POST";
  
      //post请求，参数放到请求体(httpBody)里面
      NSString *parmaterString = [NSString stringWithFormat:@"user_id=%d&city_id=%d&page_no=%d&page_size=%d",1000,1,1,20];
      mutableRequest.HTTPBody = [parmaterString dataUsingEncoding:4];
  
      //4.发送请求
      [NSURLConnection sendAsynchronousRequest:mutableRequest queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse * _Nullable response, NSData * _Nullable data, NSError * _Nullable connectionError) {
  
          NSLog(@"%@",[[NSString alloc] initWithData:data encoding:4]);
      }];
             

2. NSURLSession

• 1.GET请求

  //1、获取url
      NSString *urlString [email protected]"http://baike.baidu.com/api/openapi/BaikeLemmaCardApi?scope=103&format=json&appid=379020&bk_key=ios&bk_length=600";
      NSURL *url = [NSURL URLWithString:urlString];
  
      //2、创建请求任务
      NSURLSession *session = [NSURLSession sharedSession];
      NSURLSessionTask *task = [session dataTaskWithURL:url completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
  
          //data即为请求到的数据
          NSLog(@"%@",[[NSString alloc] initWithData:data encoding:4]);
      }];
  
      //3、开始执行任务
      [task resume];
             

• 2.POST请求

  //1、获取url
  NSString *urlString = [NSString stringWithFormat:@"http://www.baidu.com/api/category/custom?user_id=%d&city_id=%d&page_no=%d&page_size=%d",1000,1,1,20];
  NSURL *url = [NSURL URLWithString:urlString];
  
  //2、创建请求对象
  NSMutableURLRequest *mutableRequest = [NSMutableURLRequest requestWithURL:url];
  
  //3、设置请求类型、请求体
  //默认HTTPMethod = @"GET";
  mutableRequest.HTTPMethod = @"POST";
  
  //请求参数，放到请求体中
  NSString *parmaterString = [NSString stringWithFormat:@"user_id=%d&city_id=%d&page_no=%d&page_size=%d",1000,1,1,20];
  mutableRequest.HTTPBody = [parmaterString dataUsingEncoding:4];
  
  //4、创建请求任务
  NSURLSession *session = [NSURLSession sharedSession];
  NSURLSessionTask *task = [session dataTaskWithRequest:mutableRequest completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
  
      //data即为请求到的数据
      NSLog(@"%@",[[NSString alloc] initWithData:data encoding:4]);
  }];
  
  //3、开始请求数据
  [task resume];
             

  以上为NSURLConnection、NSURLSession 的GET、POST方法总结，方便对比学习，希望对你有用。本人github为https://github.com/CrazerF，里面有一些常用的控件，有兴趣可以看下。