NSURLComponents

NSURLComponents能够很方便地把URL分为几个部分

    //1.取出url的某部分
    NSString *url = @"http://en.wikipedia.org/wiki/Special:Search?search=ios";
    NSURLComponents *components = [NSURLComponents componentsWithString:url];
    NSString *host = components.host;
    NSLog(@"%@",host); //en.wikipedia.org
    
    
    //2.修改url
    components.host = @"www.baidu.com";
    NSURL *esURL = [components URL];
    NSLog(@"%@",esURL);//http://www.baidu.com/wiki/Special:Search?search=ios