//POST请求
 1 - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
 2 {
 3     // 1.URL
 4     NSURL *url = [NSURL URLWithString:@"http://localhost:8080/MJServer/login"];
 5     
 6     // 2.创建一个请求对象
 7     ASIFormDataRequest *request = [ASIFormDataRequest requestWithURL:url];
 8     
 9     // 3.设置请求参数(建议使用setPostValue多一点)
10     [request setPostValue:@"123" forKey:@"username"];
11     [request setPostValue:@"123" forKey:@"pwd"];
12     
13     // 4.开始请求
14     [request startAsynchronous];
15     
16     // 5.设置监听方法
17     __weak typeof(request) weakRequest = request;
18     [request setCompletionBlock:^{
19         NSLog(@"请求完毕--%@", [weakRequest responseString]);
20     }];
21 }