objective-c - iOS/Objective C- 来自 NSMutableURLRequest 的空响应

Question

这段代码:

NSMutableURLRequest *req = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"http://www.cnn.com"]];

[req setHTTPMethod:@"GET"];

NSURLResponse *res;
NSError *err;
NSData *data = [NSURLConnection sendSynchronousRequest:req returningResponse:&res error:&err];
NSString *html  = [NSString stringWithUTF8String:[data bytes]];

NSLog(@"email adress is %@ and password is %@, response is %@, length is %i", self.boxEmail.text, self.boxPassword.text, html, data.length);

对于 html 显示 null。出了什么问题？

NSLog'ing data.description 产生:

<3c21444f 43545950 45204854 4d4c3e0a 3c68746d 6c206c61 6e673d22 656e2d55 53223e0a 3c686561 643e0a3c

等等

Answer 1

您不能假定数据将以 NUL 终止，因此您不应调用 stringWithUTF8String。使用以下内容:

NSString *html  = [[NSString alloc] initWithData:data 
                                        encoding:NSUTF8StringEncoding];

如果您正在使用 ARC 或:

NSString *html  = [[[NSString alloc] initWithData:data 
                                         encoding:NSUTF8StringEncoding] autorelease]; 

否则。