同步加载有两种，一个是直接加载方式，另一个是发送标准同步请求后生成页面的方式。
直接方式的实现是requestWithURL:url，这种方案基本上已经很少有人用了。它可以向服务器发送普通请求，也可以向服务器下载图片。现在一般只有部分人用它下载图片。
发送标准同步请求的方式就是通过sendSynchronousRequest这个函数实现。
咱们的这个标准同步请求模块是通过代理来实现，就只贴代码，步贴使用方法了。
chttpSendSynchronousRequest.h文件
#import <Foundation/Foundation.h> @interface chttpSendSynchronousRequest : NSObject - (void)sendHttpRequest:(NSString*)sendString : (NSInteger *)resultCode : (NSString **)recvData; @end
chttpSendSynchronousRequest.m文件
- (void)sendHttpRequest:(NSString*)sendString : (NSInteger *)resultCode : (NSString **)recvData { if(nil == serverUrl) //|| (nil == sendString)) { *resultCode = -1; recvData = nil; return; } NSURL *serverNUSUrl = [NSURL URLWithString:serverUrl]; NSLog(@"%@", sendString); NSError *error = nil; NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:serverNUSUrl cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:60]; [request setHTTPMethod:@"POST"]; [request setValue:@"text.html" forHTTPHeaderField:@"Content-Type"]; NSString * sendData = sendString; NSData *postData = [sendData dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:YES]; NSString *postLength = [NSString stringWithFormat:@"%d", [postData length]]; [request setValue:postLength forHTTPHeaderField:@"Content-Length"]; NSInputStream *is = [NSInputStream inputStreamWithData:postData]; [request setHTTPBodyStream:is]; NSData *nsRecvData = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:&error]; if(nil != error) { *resultCode = -1; recvData = nil; return; } NSString * recvStrData = [[NSString alloc] initWithData:nsRecvData encoding:NSUTF8StringEncoding]; if(nil == recvStrData) { *resultCode = -1; recvData = nil; return; } NSLog(@"recvStrData[%@]",recvStrData); *recvData = recvStrData; *resultCode = 0; return; } @end
通过requestWithURL:url实现直接同步加载图像代码示例：
- (void)loadImageFromURL:(NSURL*)url { NSURLRequest* request = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:10.0]; [_data setLength:0]; _connection = [[NSURLConnection alloc] initWithRequest:request delegate:self]; } - (void)connection:(NSURLConnection *)theConnection didReceiveData:(NSData *)incrementalData { NSData * da = [[NSData alloc] initWithData:incrementalData]; [_data appendData:da]; LogInfo(@"succeeded %d byte received", [_data length]); NSString* fileName2 = [self filePath:@"image23.jpg"]; [da writeToFile:fileName2 atomically:YES]; } - (void)connection:(NSURLConnection *)theConnection didFailWithError:(NSError *)error{ // 当请求失败时的相关操作； [_data setLength:0]; } - (void)connectionDidFinishLoading:(NSURLConnection*)theConnection { LogInfo(@"succeeded %d byte received", [_data length]); }
