訪問某些網頁可能需要認證，比如JavaEye的Api。

如下方法可以做到訪問這樣的網頁，本資訊轉自：

首先需要一個Base64類

@interface Base64 : NSObject {
	
}

@end

static char *alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

@implementation Base64

+ (unsigned char *)encode:(NSData *) plainText {
	unsigned char *outputBuffer = malloc((((([plainText length] % 3) + [plainText length]) / 3) * 4) + 1);
	unsigned char *inputBuffer = (unsigned char *)[plainText bytes];
	
	NSInteger i;
	NSInteger j = 0;
	int remain;
	
	for (i = 0; i < [plainText length]; i += 3){
		remain = [plainText length] - i;
		
		outputBuffer[j++] = alphabet[(inputBuffer[i] & 0xFC) >> 2];
		outputBuffer[j++] = alphabet[((inputBuffer[i] & 0x03) << 4) | ((remain > 1) ? ((inputBuffer[i+1] & 0xF0) >> 4) : 0)];
		
		if (remain > 1){
			outputBuffer[j++] = alphabet[((inputBuffer[i+1] & 0x0F) << 2) | ((remain > 2) ? ((inputBuffer [i+2] & 0xC0) >> 6) : 0)];
		}else{
			outputBuffer[j++] = '=';
		}
		
		if (remain > 2){
			outputBuffer[j++] = alphabet[inputBuffer[i+2] & 0x3F];
		}else{
			outputBuffer[j++] = '=';
		}
	}
	
	outputBuffer[j] = '0';
	
	return outputBuffer;
}

@end

 實現：

	
	NSURL *url = [NSURL URLWithString:@"http://api.iteye.com/api/auth/verify"];  
	NSString *userName = @"username";  
	NSString *password = @"password";  
	
	NSMutableString *loginString = (NSMutableString*)[@"" stringByAppendingFormat:@"%@:%@", userName, password];  
	char *encodedLoginData = [Base64 encode:[loginString dataUsingEncoding:NSUTF8StringEncoding]];  
	NSString *authHeader = [@"Basic " stringByAppendingFormat:@"%@",   
							[NSString stringWithCString:encodedLoginData 
												 length:strlen(encodedLoginData)]];  
	NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL: url  
														   cachePolicy: NSURLRequestReloadIgnoringCacheData    
													   timeoutInterval: 3];     
	[request addValue:authHeader forHTTPHeaderField:@"Authorization"];  
	
	NSData *returnData = [NSURLConnection sendSynchronousRequest:request
											   returningResponse:nil 
														   error:nil];
	
	NSStringEncoding strEncode = CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingUTF8);
	NSString *returnStr = [[NSString alloc] initWithData:returnData encoding:strEncode];
	NSLog(@"%@", returnStr);

 把username,password替換成真實的JavaEye使用者資訊。