通过NSURLRequest获得服务器返回header

NSURL *url= [NSURLURLWithString:@"http://www.test.com"];
NSURLRequest *request= [NSURLRequestrequestWithURL: url];
NSHTTPURLResponse *response;
[NSURLConnectionsendSynchronousRequest: request returningResponse: &response error:nil];
if ([responserespondsToSelector:@selector(allHeaderFields)]){
    // 取得所有的请求的头
    NSDictionary *dictionary= [responseallHeaderFields];
    NSLog([dictionarydescription]);
    // 取得http状态码
    NSLog(@"%d",[response statusCode]);

}

 

异步访问时则要实现委托的一个方法

- (void)connection:(NSURLConnection*)connectiondidReceiveResponse:(NSURLResponse*)response {
    // 注意这里将NSURLResponse对象转换成NSHTTPURLResponse对象才能去
    NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse*)response;
    if ([responserespondsToSelector:@selector(allHeaderFields)]){
        NSDictionary *dictionary = [httpResponseallHeaderFields];
        NSLog([dictionarydescription]);
        NSLog(@"%d",[response statusCode]);

    }
}