iOS网络编程--NSConnection的同步连接与异步连接

 1 //
 2 //  ZFViewController.m
 3 //  0628-表单验证
 4 //
 5 //  Created by zfan on 14-6-28.
 6 //  Copyright (c) 2014年 zfan. All rights reserved.
 7 //
 8
 9 #import "ZFViewController.h"
10 #import "MBProgressHUD+MJ.h"
11
12 @interface ZFViewController ()
13
14 @property (weak, nonatomic) IBOutlet UITextField *userNameTextField;
15 @property (weak, nonatomic) IBOutlet UITextField *passWordTextField;
16
17 @end
18
19 @implementation ZFViewController
20
21 - (void)viewDidLoad
22 {
23     [super viewDidLoad];
24 }
25
26 - (IBAction)login:(id)sender
27 {
28     //验证账号和密码是否合法
29     if (self.userNameTextField.text.length == 0)
30     {
31         [MBProgressHUD showError:@"请输入账号"];
32         return;
33     }
34
35     if (self.passWordTextField.text.length == 0)
36     {
37         [MBProgressHUD showError:@"请输入密码"];
38         return;
39     }
40
41     //取出账号和密码
42     NSString *userName = self.userNameTextField.text;
43     NSString *password = self.passWordTextField.text;
44
45     //生成URL
46     NSString *urlPath = [NSString stringWithFormat:@"http://192.168.1.101:8080/ZFServer/login?username=%@&pwd=%@", userName, password];
47     NSURL *url = [NSURL URLWithString:urlPath];
48
49     //生成连接
50     NSURLRequest *urlRequest = [NSURLRequest requestWithURL:url];
51
52     //建立连接并接收返回数据(同步执行)
53 //    NSData *loginData = [NSURLConnection sendSynchronousRequest:urlRequest returningResponse:nil error:nil];
54
55
56     //建立连接并接收返回数据(异步执行)
57     NSOperationQueue *queue = [[NSOperationQueue alloc] init];
58     [NSURLConnection sendAsynchronousRequest:urlRequest queue:queue completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {
59         NSData *loginData = data;
60         NSLog(@"%ld", (unsigned long)loginData.length);
61     }];
62
63     //打印返回的数据长度
64     NSLog(@"%@", self.userNameTextField.text);
65     NSLog(@"%@", self.passWordTextField.text);
66 //    NSLog(@"%ld", (unsigned long)loginData.length);
67 }
68
69 @end

知识要点:

1>通过NSString类方法拼接字符串,生成完整的URL路径;

2>通过NSURLRequest的类方法,利用URL建立一个NSURLRequest连接实例;

3>通过NSConnection的类方法建立连接并接受返回数据,可通过同步方式和异步方式实现:

　　3.1>同步方式

[NSURLConnection sendSynchronousRequest:urlRequest returningResponse:nil error:nil];

　　此方法不会新建线程,返回值为NSData,由于未新建线程,因此在该方法未完成前,线程不会继续向下运行,容易造成卡死;

　　3.2>异步方式

NSOperationQueue *queue = [[NSOperationQueue alloc] init];
[NSURLConnection sendAsynchronousRequest:urlRequest queue:queue completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {
　　NSData *loginData = data;
　　NSLog(@"%ld", (unsigned long)loginData.length);
}];

　　此方法会建立一个新的线程用于接受网络端返回数据,返回值为void,当数据接受完毕后会执行block中的语句;

iOS网络编程--NSConnection的同步连接与异步连接