iOS网络请求

1.NSData

NSData相当于一个GET请求

 NSString *urlStrig = @"http://888s?name=张三&pwd=123e";
   urlStrig = [urlStrig stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet URLQueryAllowedCharacterSet]];
   NSURL *url = [NSURL URLWithString:urlStrig];
   NSData *data = [NSData dataWithContentsOfURL:url];

2.NSURLConnection

NSString *urlStrig = @"http://888s?name=张三&pwd=123e";
    urlStrig = [urlStrig stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet URLQueryAllowedCharacterSet]];
NSURL *url = [NSURL URLWithString:urlStrig];
NSURLRequest *request = [NSURLRequest requestWithURL:url];//默认为GET

//同步请求
NSURLResponse *response = nil;
NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:nil];

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

}];
一般http的GET请求使用sendAsynchronousRequest发送一个异步请求就可以完成了，如果要下载大文件最好使用代理方式来处理

//此方法会初始化一个NSURLConnection对象，并且会马上发送请求
//self遵守的代理为NSURLConnectionDataDelegate
[NSURLConnection connectionWithRequest:request delegate:self]

NSURLConnectionDataDelegate代理方法

/**
 接受到服务器的响应就会调用此方法

 @param response 响应,可以通过响应回去文件的大小
 */
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response{
}

/**
 接收到服务器返回的实体数据时调用
 此方法可能会被调用多次

 @param data 本次返回的数据
 */
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{
}

/**
 所有数据接受完毕调用
 通常在该方法中处理服务器返回的数据
 */
- (void)connectionDidFinishLoading:(NSURLConnection *)connection{
}

/**
 请求错误时会调用
 */
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error{


}
2POST
参数写在请求体中

NSString *urlStrig = @"http://ip:port/login";
urlStrig = [urlStrig stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet URLQueryAllowedCharacterSet]];
NSURL *url = [NSURL URLWithString:urlStrig];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
request.HTTPMethod = @"POST";
request.HTTPBody = [@"account=12345&pwd=123" dataUsingEncoding:NSUTF8StringEncoding];
[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse * _Nullable response, NSData * _Nullable data, NSError * _Nullable connectionError) {
        
}];

3.NSURLSession

使用方法为获取session对象，使用session创建一个请求任务，开始任务即可。
请求任务:
NSURLSessionTask是URL会话中任务的基类,一般不直接使用，主要使用的是其子类

1.获取NSURLSession对象
NSURLSession *session = [NSURLSession sharedSession];
2.使用session对象创建一个普通的请求任务
NSURL *url = [NSURL URLWithString:@""];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
NSURLSessionDataTask *task = [session dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
        
}];
3.开启任务
[task resume];

4.AFNetWorking

NSMutableDictionary *param = [NSMutableDictionary dictionary];
param[@"username"] = @"张三";
param[@"age"] = @(20);
    
NSString *url = @"";
AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
//请求超时时间
manager.requestSerializer.timeoutInterval = 30;
//告诉返回的数据（responseObject）为NSDictionary对象,默认为AFJSONResponseSerializer
manager.responseSerializer = [AFJSONResponseSerializer serializer];
//告诉返回的数据（responseObject）为NSXMLParser对象
//manager.responseSerializer = [AFXMLParserResponseSerializer serializer];
//告诉返回的数据（responseObject）为原数据（NSData）
//manager.responseSerializer = [AFHTTPResponseSerializer serializer];
    
[manager GET:url parameters:param success:^(AFHTTPRequestOperation *operation, id responseObject) {
        
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
    
}];

//文件上传

NSString *urlString = @"";
AFHTTPRequestOperationManager *mgr = [AFHTTPRequestOperationManager manager];
//普通参数
NSMutableDictionary *params = [NSMutableDictionary dictionary];
[params setObject:@"张三" forKey:@"username"];
[mgr POST:urlString parameters:params constructingBodyWithBlock:^(id<AFMultipartFormData> formData) {
    NSData *imageData = UIImagePNGRepresentation([UIImage imageNamed:@""]);   
     /**
     拼接文件参数

     @fileData : 要上传的文件数据
     @name : 后台定义文件的参数名
     @fileName ： 上传到服务器的文件名称
     @mimeType : 上传的文件类型
   */
    [formData appendPartWithFileData:imageData name:@"file" fileName:@"text.png" mimeType:@"image/png"];
} success:^(AFHTTPRequestOperation *operation, id responseObject) {
        
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        
}];