NSURLSession发送POST请求

#import "ViewController.h"

@interface ViewController ()<NSURLSessionDataDelegate>

@property (nonatomic, strong) NSMutableData   *totalData;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    self.totalData = [[NSMutableData alloc]init];
}

-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
//    [self sendPost];
    [self sendPostWithDelegate];
    
}

-(void)sendPost
{
    //直接发送POST请求
    NSURL *url = [NSURL URLWithString:@"http://www.yahoo.com"];
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
    request.HTTPMethod = @"POST";
    
    NSString *username = @"zhaosi";
    NSString *password = @"lsp188";
    NSString *bodyStr = [NSString stringWithFormat:@"username=%@&password=%@",username,password];
    request.HTTPBody = [bodyStr dataUsingEncoding:NSUTF8StringEncoding];
    
    NSURLSession *session = [NSURLSession sharedSession];
    NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
        if (error == nil) {
            
            NSString *resultStr = [[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];
            NSLog(@"-------%lu",resultStr.length);
        }
        else
        {
            NSLog(@"%@",error.description);
        }
    }];
    //必须启动任务，否则不会走block中的回调
    [dataTask resume];
}

-(void)sendPostWithDelegate
{//通过代理完成请求
    NSURL *url = [NSURL URLWithString:@"http://www.yahoo.com"];
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
    request.HTTPMethod = @"POST";
    
    NSString *username = @"zhaosi";
    NSString *password = @"lsp188";
    NSString *bodyStr = [NSString stringWithFormat:@"username=%@&password=%@",username,password];
    request.HTTPBody = [bodyStr dataUsingEncoding:NSUTF8StringEncoding];
    
    //自定义会话对象设置代理，
    NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration] delegate:self delegateQueue:[NSOperationQueue mainQueue]];//设置代理方法在哪个线程执行
    
    NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request];
    [dataTask resume];
}


#pragma mark NSURLConnectionDataDelegate
- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveResponse:(NSURLResponse *)response completionHandler:(void (^)(NSURLSessionResponseDisposition disposition))completionHandler
{//接收到服务器响应后，调用的方法
    NSLog(@"didReceiveResponse");
    //需要通过调用completionHandler告诉系统应该如何处理服务器返回的数据
    completionHandler(NSURLSessionResponseAllow);//NSURLSessionResponseAllow表示接收返回的数据
}

-(void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveData:(NSData *)data
{//接收到服务器响应数据的时候会调用，该方法可能调用多次
    
    [self.totalData appendData:data];
    NSLog(@"%lu---",self.totalData.length);
}

-(void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error
{//请求完成 或者失败的时候调用
    NSLog(@"didCompleteWithError");
    //在这里 解析数据
    NSLog(@"%@",[[NSString alloc]initWithData:self.totalData encoding:NSUTF8StringEncoding]);
}

@end