从 URL 获取域/主​​机名的最快方法是什么?

本文介绍了从 URL 获取域/主​​机名的最快方法是什么?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我需要浏览大量的字符串 url 列表并从中提取域名.

I need to go through a large list of string url's and extract the domain name from them.

例如:

http://www.stackoverflow/questions 会提取 www.stackoverflow

我最初使用的是 new URL(theUrlString).getHost() 但 URL 对象的初始化为该过程增加了大量时间并且似乎不需要.

I originally was using new URL(theUrlString).getHost() but the URL object initialization adds a lot of time to the process and seems unneeded.

是否有一种更快的方法来提取同样可靠的主机名?

Is there a faster method to extract the host name that would be as reliable?

谢谢

我的错误，是 www.将包含在上面的域名示例中.此外，这些网址可能是 http 或 https

My mistake, yes the www. would be included in domain name example above. Also, these urls may be http or https

推荐答案

如果你想处理 https 等，我建议你这样做:

If you want to handle https etc, I suggest you do something like this:

int slashslash = url.indexOf("//") + 2;
domain = url.substring(slashslash, url.indexOf('/', slashslash));

请注意，这包括 www 部分(就像 URL.getHost() 会做的那样)，它实际上是域名的一部分.

Note that this is includes the www part (just as URL.getHost() would do) which is actually part of the domain name.

通过评论请求编辑

这里有两种可能有用的方法:

Here are two methods that might be helpful:

/**
 * Will take a url such as http://www.stackoverflow and return www.stackoverflow
 * 
 * @param url
 * @return
 */
public static String getHost(String url){
    if(url == null || url.length() == 0)
        return "";

    int doubleslash = url.indexOf("//");
    if(doubleslash == -1)
        doubleslash = 0;
    else
        doubleslash += 2;

    int end = url.indexOf('/', doubleslash);
    end = end >= 0 ? end : url.length();

    int port = url.indexOf(':', doubleslash);
    end = (port > 0 && port < end) ? port : end;

    return url.substring(doubleslash, end);
}


/**  Based on : http://grepcode/file/repository.grepcode/java/ext/com.google.android/android/2.3.3_r1/android/webkit/CookieManager.java#CookieManager.getBaseDomain%28java.lang.String%29
 * Get the base domain for a given host or url. E.g. mail.google will return google
 * @param host 
 * @return 
 */
public static String getBaseDomain(String url) {
    String host = getHost(url);

    int startIndex = 0;
    int nextIndex = host.indexOf('.');
    int lastIndex = host.lastIndexOf('.');
    while (nextIndex < lastIndex) {
        startIndex = nextIndex + 1;
        nextIndex = host.indexOf('.', startIndex);
    }
    if (startIndex > 0) {
        return host.substring(startIndex);
    } else {
        return host;
    }
}

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