1. 常用類(lèi)
NSURL：請(qǐng)求地址
-
NSURLRequest：一個(gè)NSURLRequest對(duì)象就代表一個(gè)請(qǐng)求，它包含的信息有
- 一個(gè)NSURL對(duì)象
- 請(qǐng)求方法、請(qǐng)求頭、請(qǐng)求體
- 請(qǐng)求超時(shí)
NSMutableURLRequest：NSURLRequest的子類(lèi)
-
NSURLConnection
- 負(fù)責(zé)發(fā)送請(qǐng)求，建立客戶端和服務(wù)器的連接
- 發(fā)送數(shù)據(jù)給服務(wù)器，并收集來(lái)自服務(wù)器的響應(yīng)數(shù)據(jù)
2. NSURLConnection的使用步驟
- 使用NSURLConnection發(fā)送請(qǐng)求的步驟很簡(jiǎn)單
- 創(chuàng)建一個(gè)NSURL對(duì)象，設(shè)置請(qǐng)求路徑
- 傳入NSURL創(chuàng)建一個(gè)NSURLRequest對(duì)象，設(shè)置請(qǐng)求頭和請(qǐng)求體
- 使用NSURLConnection發(fā)送請(qǐng)求
NSURLConnection的請(qǐng)求過(guò)程.png
3. NSURLConnection發(fā)送請(qǐng)求
-
NSURLConnection常見(jiàn)的發(fā)送請(qǐng)求方法有以下幾種
- 3.1同步請(qǐng)求
+ (NSData *)sendSynchronousRequest:(NSURLRequest *)request returningResponse:(NSURLResponse **)response error:(NSError **)error;
- 3.2異步請(qǐng)求：根據(jù)對(duì)服務(wù)器返回?cái)?shù)據(jù)的處理方式的不同，又可以分為2種
- 3.2.1 block回調(diào)
+ (void)sendAsynchronousRequest:(NSURLRequest*) request queue:(NSOperationQueue*) queue
completionHandler:(void (^)(NSURLResponse* response, NSData* data, NSError* connectionError)) handler;
- 3.2.2 代理
- (id)initWithRequest:(NSURLRequest *)request delegate:(id)delegate;
+ (NSURLConnection*)connectionWithRequest:(NSURLRequest *)request delegate:(id)delegate;
- (id)initWithRequest:(NSURLRequest *)request delegate:(id)delegate startImmediately:(BOOL)startImmediately;
- 在startImmediately = NO的情況下，需要調(diào)用start方法開(kāi)始發(fā)送請(qǐng)求
- (void)start;
成為NSURLConnection的代理，最好遵守NSURLConnectionDataDelegate協(xié)議
NSURLConnectionDataDelegate協(xié)議中的代理方法
開(kāi)始接收到服務(wù)器的響應(yīng)時(shí)調(diào)用
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response;
接收到服務(wù)器返回的數(shù)據(jù)時(shí)調(diào)用（服務(wù)器返回的數(shù)據(jù)比較大時(shí)會(huì)調(diào)用多次）
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data;
服務(wù)器返回的數(shù)據(jù)完全接收完畢后調(diào)用
- (void)connectionDidFinishLoading:(NSURLConnection *)connection;
請(qǐng)求出錯(cuò)時(shí)調(diào)用（比如請(qǐng)求超時(shí)）
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error;
4. NSMutableURLRequest
- NSMutableURLRequest是NSURLRequest的子類(lèi)，常用方法有
設(shè)置請(qǐng)求超時(shí)等待時(shí)間（超過(guò)這個(gè)時(shí)間就算超時(shí)，請(qǐng)求失敗）
- (void)setTimeoutInterval:(NSTimeInterval)seconds;
設(shè)置請(qǐng)求方法（比如GET和POST）
- (void)setHTTPMethod:(NSString *)method;
設(shè)置請(qǐng)求體
- (void)setHTTPBody:(NSData *)data;
設(shè)置請(qǐng)求頭
- (void)setValue:(NSString *)value forHTTPHeaderField:(NSString *)field;
5. 創(chuàng)建GET和POST請(qǐng)求
- 創(chuàng)建GET請(qǐng)求
NSString *urlStr = [@"http://120.25.226.186:32812/login?username=123&pwd=123" stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSURL *url = [NSURL URLWithString:urlStr];
// 2. 創(chuàng)建請(qǐng)求對(duì)象
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
// 3. 發(fā)送GET請(qǐng)求
[NSURLConnection sendAsynchronousRequest:request queue:[[NSOperationQueue alloc] init] completionHandler:^(NSURLResponse * _Nullable response, NSData * _Nullable data, NSError * _Nullable connectionError) {
// 4. 解析數(shù)據(jù)
NSLog(@"網(wǎng)絡(luò)請(qǐng)求到的數(shù)據(jù):%@",[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]);
NSHTTPURLResponse * httpResponse = (NSHTTPURLResponse *)response;
NSLog(@"%zd",httpResponse.statusCode);
NSLog(@"線程：%@",[NSThread currentThread]);
}];
- 創(chuàng)建POST請(qǐng)求
// 1. 確定請(qǐng)求路徑
NSURL * url = [NSURL URLWithString:@"http://120.25.226.186:32812/login"];
// 2. 創(chuàng)建可變的請(qǐng)求對(duì)象
NSMutableURLRequest * request = [NSMutableURLRequest requestWithURL:url];
// 3. 修改請(qǐng)求方法,POST 必須大寫(xiě)
request.HTTPMethod = @"POST";
// 設(shè)置屬性,請(qǐng)求超時(shí)(如果超過(guò)10秒，不管有沒(méi)有接收到數(shù)據(jù)，客戶端都認(rèn)為請(qǐng)求失敗)
request.timeoutInterval = 10;
// 設(shè)置請(qǐng)求頭 User-Agent
[request setValue:@"iOS 8.1" forHTTPHeaderField:@"User-Agent"];
// 4. 設(shè)置請(qǐng)求體信息，字符串 --> NSData
request.HTTPBody = [@"username=520it&pwd=520it&type=JSON" dataUsingEncoding:NSUTF8StringEncoding];
// 5. 發(fā)送請(qǐng)求
[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse * _Nullable response, NSData * _Nullable data, NSError * _Nullable connectionError) {
// 6. 解析數(shù)據(jù), NSData --> NSString
NSLog(@"解析到的數(shù)據(jù)為:%@",[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]);
}];
