iOS之网络请求
iOS中遵循较为安全的HTTPS安全超文本协议，若想访问遵循HTTP协议的网页需要进行以下设置：
将代码<key>NSAppTransportSecurity</key>
<dict>
<key>NSAllowsArbitraryLoads</key>
<true/>
</dict>
复制到
路径下；
或者在info.plist文件中添加以下字段
请求方式分为GET和POST两种方式；每种方式又包含同步和异步两种形式；同步会是应用程序出现卡顿现象，这里只介绍异步的形式。
在iOS7之前使用NSURLConnection来进行网络的请求，iOS7之后前面的方法被重构，改为NSURLSession。先介绍NSURLConnection，虽然被重构但还是可以运行的：
#pragma mark - NSURLConnection - 异步get请求
- (IBAction)getAsynchronousRequest:(UIButton *)sender {
//1.创建url
NSURL *url = [NSURL URLWithString:GET_URL];//GET_URL是宏定义的网址，创建Header File，在其中宏定义网址。
宏定义：：：：：
#define GET_URL @"http://ipad-bjwb.bjd.com.cn/DigitalPublication/publish/Handler/APINewsList.ashx?date=20131129&startRecord=1&len=5&udid=1234567890&terminalType=Iphone&cid=213"
#define POST_URL @"http://ipad-bjwb.bjd.com.cn/DigitalPublication/publish/Handler/APINewsList.ashx"
#define POST_BODY @"date=20131129&startRecord=1&len=5&udid=1234567890&terminalType=Iphone&cid=213"
//2.创建请求
NSURLRequest *request = [NSURLRequest requestWithURL:url];
//3.连接服务器
//方法一：Block方法实现，//参数1：请求对象 //参数2：线程队列 //参数3：block
[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse * _Nullable response, NSData * _Nullable data, NSError * _Nullable connectionError) {
if (connectionError == nil) {
//4.解析
NSDictionary *dic = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments error:nil];
NSLog(@"dic = %@", dic);
//先开辟子线程解析数据
//然后在主线程里刷新UI
}
}];
//方法二：使用delegate实现<NSURLConnectionDataDelegate>,将上面的3.4.两步替换为，同时使用先关代理方法
//[NSURLConnection connectionWithRequest:request delegate:self];
}
#pragma mark - NSURLConnectionDataDelegate相关的代理方法
//服务器开始响应
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
self.resultData = [NSMutableData new];//初始化数据
}
//开始接收数据这个方法会重复执行，得到的每段数据拼接在一起就可以了
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
[self.resultData appendData:data];
}
//结束服务器
- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
//进行数据解析（根据url链接到的具体内容进行解析）
NSDictionary *dic = [NSJSONSerialization JSONObjectWithData:self.resultData options:NSJSONReadingAllowFragments error:nil];
NSLog(@"dic = %@", dic);
}
#pragma mark -NSURLConnection - 异步post请求
- (IBAction)postAsynchronousRequest:(UIButton *)sender {
//1.创建url
NSURL *url = [NSURL URLWithString:POST_URL];
//2.创建请求
NSMutableURLRequest *mutableRequest = [NSMutableURLRequest requestWithURL:url];
//2.5设置body
//创建一个链接字符串
NSString *dataString = POST_BODY;
//对连接字符串进行编码
NSData *postData = [dataString dataUsingEncoding:NSUTF8StringEncoding];
//设置请求格式
[mutableRequest setHTTPMethod:@"POST"];
//设置请求体
[mutableRequest setHTTPBody:postData];
//3.链接服务器
[NSURLConnection sendAsynchronousRequest:mutableRequest queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse * _Nullable response, NSData * _Nullable data, NSError * _Nullable connectionError) {
if (connectionError == nil) {
NSDictionary *dic = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments error:nil];
}
}];
}
#pragma mark - NSURLSession - get请求block实现
- (IBAction)getRequest:(UIButton *)sender {
//方式一：使用block
//1.创建url
NSURL *url = [NSURL URLWithString:GET_URL];
//2.创建请求NSURLRequest
NSURLRequest *request = [NSURLRequest requestWithURL:url];
//2.创建session对象
NSURLSession *session = [NSURLSession sharedSession];
//3.创建task请求任务
NSURLSessionDataTask *task = [session dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
//4.解析相关的数据//这里block执行步骤比较靠后，不是在//2.创建session对象之后马上执行
if (error == nil) {
NSDictionary *dic = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments error:nil];
}
}];
//5.核心步：启动任务【千万不要忘记】============
//原因：NSURLSessionTask实例出来的任务处于挂起状态，如果不启动，不会走block中的实现部分
[task resume];
#pragma mark - NSURLSession - get请求协议实现
NSURL *url = [NSURL URLWithString:GET_URL];
//2.创建session
//参数1：模式的设置
/*
* defaultSessionConfiguration 默认会话模式
* ephemeralSessionConfiguration 瞬时会话模式
* backgroundSessionConfigurationWithIdentifier 后台会话模式
*/
//参数2：代理
//参数3：主线程队列
NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration] delegate:self delegateQueue:[NSOperationQueue mainQueue]];//遵循协议<NSURLSessionDataDelegate>
//3.创建task
NSURLSessionDataTask *task = [session dataTaskWithURL:url];
//4.启动
[task resume];
#pragma mark - NSURLSessionDataDelegate协议的实现方法
//服务器开始响应
- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveResponse:(NSURLResponse *)response completionHandler:(void (^)(NSURLSessionResponseDisposition))completionHandler {
//允许服务器响应[在这个地方只有允许服务器响应了才会接收到数据]
completionHandler(NSURLSessionResponseAllow);
//初始化data稍后进行片段的拼接存储
self.resultData = [NSMutableData data];
}
//接收数据拼接
- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveData:(NSData *)data {
//反复执行，然后拼接相关的片段
[self.resultData appendData:data];
}
//数据接收完成，网络请求结束
- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error {
//解析
if (error == nil) {
NSDictionary *dic = [NSJSONSerialization JSONObjectWithData:self.resultData options:NSJSONReadingAllowFragments error:nil];
NSLog(@"dic = %@", dic);
}
}
#pragma mark - NSURLSession - post请求
- (IBAction)postRequest:(UIButton *)sender {
//1.创建url
NSURL *url = [NSURL URLWithString:POST_URL];
//2.创建请求
NSMutableURLRequest *mutableRequest = [NSMutableURLRequest requestWithURL:url];
//2.5核心设置body
NSString *bodyString = POST_BODY;
NSData *postData = [bodyString dataUsingEncoding:NSUTF8StringEncoding];
[mutableRequest setHTTPMethod:@"POST"];
[mutableRequest setHTTPBody:postData];
//3.创建session对象
NSURLSession *session = [NSURLSession sharedSession];
//4.创建task对象
NSURLSessionDataTask *task = [session dataTaskWithRequest:mutableRequest completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
//5.解析
if (error == nil) {
NSDictionary *dic = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments error:nil];
NSLog(@"dic = %@", dic);
}
}];
//6.启动任务
[task resume];
}
