get 请求

#pragma mark - GET登录
- (void)getLogon
{
    // 1. URL
    NSString *urlStr = [NSString stringWithFormat:@"http://localhost/login.php?username=%@&password=%@", self.userName.text, self.userPwd.text];
    
    NSURL *url = [NSURL URLWithString:urlStr];
    
    // 2. Request
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    
    // 3. Connection
    // 1> 登录完成之前,不能做后续工作!
    // 2> 登录进行中,可以允许用户干点别的会更好!
    // 3> 让登录操作在其他线程中进行,就不会阻塞主线程的工作
    // 4> 结论:登陆也是异步访问,中间需要阻塞住
    [NSURLConnection sendAsynchronousRequest:request queue:[[NSOperationQueue alloc] init] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {
        
        if (connectionError == nil) {
            // 网络请求结束之后执行!
            // 将Data转换成字符串
            NSString *str = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
            
            // num = 2
            NSLog(@"%@ %@", str, [NSThread currentThread]);
            
            // 更新界面
            [[NSOperationQueue mainQueue] addOperationWithBlock:^{
                self.logonResult.text = @"登录完成";
            }];
        }
    }];
    
    // num = 1
    NSLog(@"come here %@", [NSThread currentThread]);
    
    NSURLResponse *response = nil;
    // 1. &response真的理解了吗?
    // 2. error:为什么是NULL,而不是nil
    // NULL是C语言的 = 0
    // 在C语言中,如果将指针的地址指向0就不会有危险
    
    // nil是OC的,是一个空对象发送消息不会出问题
//    [response MIMEType];
    [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:NULL];
}

#pragma mark - POST登录
- (void)postLogon
{
    // 1. URL
    NSURL *url = [NSURL URLWithString:@"http://localhost/login.php"];
    
    // 2. 请求(可以改的请求)
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
    // ? POST
    // 默认就是GET请求
    request.HTTPMethod = @"POST";
    // ? 数据体
    NSString *str = [NSString stringWithFormat:@"username=%@&password=%@", self.userName.text, self.userPwd.text];
    // 将字符串转换成数据
    request.HTTPBody = [str dataUsingEncoding:NSUTF8StringEncoding];
    
    // 3. 连接,异步
    [NSURLConnection sendAsynchronousRequest:request queue:[[NSOperationQueue alloc] init] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {
        
        if (connectionError == nil) {
            // 网络请求结束之后执行!
            // 将Data转换成字符串
            NSString *str = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
            
            // num = 2
            NSLog(@"%@ %@", str, [NSThread currentThread]);
            
            // 更新界面
            [[NSOperationQueue mainQueue] addOperationWithBlock:^{
                self.logonResult.text = str;
            }];
        }
    }];
    
    // num = 1
    NSLog(@"come here %@", [NSThread currentThread]);
}

- (void)getLogon
{
    // 1. URL
    NSString *urlStr = [NSString stringWithFormat:@"http://localhost/login.php?username=%@&password=%@", self.userName.text, self.myPwd];
    
    NSLog(@"%@", self.myPwd);
    
    NSURL *url = [NSURL URLWithString:urlStr];
    
    // 2. Request
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    
    // 3. 连接,已经10多岁了
    // 是一个很古老的技术
    NSURLConnection *connection = [NSURLConnection connectionWithRequest:request delegate:self];
    
    // 开始工作,在很多多线程技术中,start run
    dispatch_async(dispatch_queue_create("demo", DISPATCH_QUEUE_CONCURRENT), ^{
        [connection start];
    });
}

#pragma mark - NSURLConnectionDataDelegate代理方法
#pragma mark 接受到响应
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
    // 准备工作
    // 按钮点击就会有网络请求,为了避免重复开辟空间
    if (!self.data) {
        self.data = [NSMutableData data];
    } else {
        [self.data setData:nil];
    }
}

#pragma mark 接收到数据,如果数据量大,例如视频,会被多次调用
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
    // 拼接数据,二进制流的体现位置
    [self.data appendData:data];
}

#pragma mark 接收完成,做最终的处理工作
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    // 最终处理
    NSString *str = [[NSString alloc] initWithData:self.data encoding:NSUTF8StringEncoding];
    
    NSLog(@"%@ %@", str, [NSThread currentThread]);
}

#pragma mark 出错处理,网络的出错可能性非常高
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
    NSLog(@"%@", error.localizedDescription);
}

// 更新界面
            [[NSOperationQueue mainQueue] addOperationWithBlock:^{
                self.logonResult.text = str;
            }];