傳智ios至2015年4月6.多線程網(wǎng)絡

網(wǎng)絡

NSURLConnectioniOS學院常用類NSURL：請求地址NSURLRequest：一個NSURLRequest對象就代表一個請求，它包含的信息有一個NSURL對象請求方法、請求頭、請求體請求超時…

…NSMutableURLRequest：NSURLRequest的子類NSURLConnection負責發(fā)送請求，建立客戶端和服務器的連接發(fā)送NSURLRequest的數(shù)據(jù)給服務器，并收集來自服務器的響應數(shù)據(jù)NSURLConnection的使用步驟使用NSURLConnection發(fā)送請求的步驟很簡單創(chuàng)建一個NSURL對象，設置請求路徑傳入NSURL創(chuàng)建一個NSURLRequest對象，設置請求頭和請求體使用NSURLConnection發(fā)送NSURLRequestNSURLRequestNSURL請求頭請求體NSURLConnection服務器NSURLConnection發(fā)送請求NSURLConnection常見的發(fā)送請求方法有以下幾種同步請求+(NSData*)sendSynchronousRequest:(NSURLRequest*)requestreturningResponse:(NSURLResponse**)responseerror:(NSError**)error;異步請求：根據(jù)對服務器返回數(shù)據(jù)的處理方式的不同，又可以分為2種block回調(diào)+(void)sendAsynchronousRequest:(NSURLRequest*)request

queue:(NSOperationQueue*)queue

completionHandler:(void(^)(NSURLResponse*response,NSData*data,NSError*connectionError))handler;NSURLConnection發(fā)送請求代理-(id)initWithRequest:(NSURLRequest*)requestdelegate:(id)delegate;+(NSURLConnection*)connectionWithRequest:(NSURLRequest*)requestdelegate:(id)delegate;-(id)initWithRequest:(NSURLRequest*)requestdelegate:(id)delegatestartImmediately:(BOOL)startImmediately;在startImmediately

=

NO的情況下，需要調(diào)用start方法開始發(fā)送請求-(void)start;成為NSURLConnection的代理，最好遵守NSURLConnectionDataDelegate協(xié)議NSURLConnectionDelegateNSURLConnectionDataDelegate協(xié)議中的代理方法開始接收到服務器的響應時調(diào)用-(void)connection:(NSURLConnection*)connectiondidReceiveResponse:(NSURLResponse*)response;接收到服務器返回的數(shù)據(jù)時調(diào)用（服務器返回的數(shù)據(jù)比較大時會調(diào)用多次）-(void)connection:(NSURLConnection*)connectiondidReceiveData:(NSData*)data;服務器返回的數(shù)據(jù)完全接收完畢后調(diào)用-(void)connectionDidFinishLoading:(NSURLConnection*)connection;請求出錯時調(diào)用（比如請求超時）-(void)connection:(NSURLConnection*)connectiondidFailWithError:(NSError*)error;NSMutableURLRequestNSMutableURLRequest是NSURLRequest的子類，常用方法有設置請求超時等待時間（超過這個時間就算超時，請求失敗）-(void)setTimeoutInterval:(NSTimeInterval)seconds;設置請求方法（比如GET和POST）-(void)setHTTPMethod:(NSString*)method;設置請求體-(void)setHTTPBody:(NSData*)data;設置請求頭-(void)setValue:(NSString*)valueforHTTPHeaderField:(NSString*)field;創(chuàng)建GET和POST請求創(chuàng)建GET請求NSString*urlStr=[@""stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];NSURL*url=[NSURLURLWithString:urlStr];NSMutableURLRequest*request=[NSMutableURLRequestrequestWithURL:url];創(chuàng)建POST請求NSString*urlStr=@"";NSURL*url=[NSURLURLWithString:urlStr];NSMutableURLRequest*request=[NSMutableURLRequestrequestWithURL:url];request.HTTPMethod=@"POST";//請求體NSString*bodyStr=@"username=123&pwd=123";request.HTTPBody=[bodyStrdataUsingEncoding:NSUTF8StringEncoding];發(fā)送JSON給服務器如何發(fā)送JSON給服務器一定要使用POST請求設置請求頭[requestsetValue:@"application/json"

forHTTPHeaderField:@"Content-Type"];設置JSON數(shù)據(jù)為請求體檢測網(wǎng)絡狀態(tài)在網(wǎng)絡應用中，需要對用戶設備的網(wǎng)絡狀態(tài)進行實時監(jiān)控，目的是讓用戶了解自己的網(wǎng)絡狀態(tài)，防止一些誤會（比如怪應用無能）根據(jù)用戶的網(wǎng)絡狀態(tài)進行智能處理，節(jié)省用戶流量，提高用戶體驗WIFI\3G網(wǎng)絡：自動下載高清圖片低速網(wǎng)絡：只下載縮略圖沒有網(wǎng)絡：只顯示離線的緩存數(shù)據(jù)蘋果官方提供了一個叫Reachability的示例程序，便于開發(fā)者檢測網(wǎng)絡狀態(tài)

ReachabilityReachability的使用步驟添加框架SystemConfiguration.framework添加源代碼包含頭文件#import"Reachability.h"Reachability常見用法//是否WIFI+(BOOL)IsEnableWIFI{

return([[Reachability

reachabilityForLocalWiFi]currentReachabilityStatus]!=NotReachable);}//是否3G+(BOOL)IsEnable3G{

return([[Reachability

reachabilityForInternetConnection]currentReachabilityStatus]!=NotReachable);}網(wǎng)絡監(jiān)控[[NSNotificationCenterdefaultCenter]addObserver:selfselector:@selector(reachabilityChanged:)name:kReachabilityChangedNotificationobject:nil];Reachability=[ReachabilityreachabilityForInternetConnection];[