我已經給出了包含任何有效url的字符串。 我必須從給定的網址找到唯一的網站名稱。 我也忽略子域。如何從任何字符串url獲取網站的名稱
像
http://www.yahoo.com => yahoo
www.google.co.in => google
http://in.com => in
http://india.gov.in/ => india
https://in.yahoo.com/ => yahoo
http://philotheoristic.tumblr.com/ =>tumblr
http://philotheoristic.tumblr.com/
https://in.movies.yahoo.com/ =>yahoo
如何做到這一點
正則表達式可以幫助你：
String str = "www.google.co.in";
String [] res = str.split("(\\.|//)+(?=\\w)");
System.out.println(res[1]);
正則表達式是表示一組字符串的方式。該組由與表達式匹配的任何字符串組成。在上面的代碼中，用作split參數的字符串是匹配的正則表達式：Any「。」接着是字母數字文本或「//」後跟字母數字文本。 所以這些「。」和「//」子字符串是用於分割字符串的分隔符，第一個是網站名稱。
在「www.google.co.in」中，字符串將被拆分爲：goole, co, in。由於解決方案正在使用spit數組的第一個元素，因此結果爲：google。
我希望我能像你一樣瞭解經常的exp。你能解釋一下你的經常性的前例如何，我可以學到一些東西嗎？ –
@KickButtowski我編輯了我的答案以包含解釋。 –
謝謝，你知道任何容易理解的外國人常規exp教程嗎？ –
呦可以利用URL
從技術文檔 - http://docs.oracle.com/javase/tutorial/networking/urls/urlInfo.html
import java.net.*;
import java.io.*;
public class ParseURL {
public static void main(String[] args) throws MalformedURLException {
URL aURL = new URL("http://example.com:80/docs/books/tutorial"
+ "/index.html?name=networking#DOWNLOADING");
System.out.println("protocol = " + aURL.getProtocol());
System.out.println("authority = " + aURL.getAuthority());
System.out.println("host = " + aURL.getHost());
System.out.println("port = " + aURL.getPort());
System.out.println("path = " + aURL.getPath());
System.out.println("query = " + aURL.getQuery());
System.out.println("filename = " + aURL.getFile());
System.out.println("ref = " + aURL.getRef());
}
}
這裏是由程序顯示的輸出：
protocol = http
authority = example.com:80
host = example.com // name of website
port = 80
path = /docs/books/tutorial/index.html
query = name=networking
filename = /docs/books/tutorial/index.html?name=networking
ref = DOWNLOADING
因此，通過使用aURL.getHost()你可以得到網站名稱。要忽略子域，您可以用"."分割它，因此它變成aURL.getHost().split(".")[0]以獲取名稱。
不錯的答案，但你怎麼會最終只是例子？ –
沒有任何可能的方法從url找出有效的網站名稱。但是，如果你正試圖削減URL字符串的特定部分，你可以通過字符串操作如下
if(url.endsWith("co.in"){
website = url.substring(indexOfLostThirdDot, indexofco.in)
}
我發現了相似的內容做到這一點。雖然有些不同。
http://www.yahoo.com => Yahoo
http://www.google.co.in => Google
http://in.com => In.com Offers Videos, News, Photos, Celebs, Live TV Channels.....
http://india.gov.in/ => National Portal of India
https://in.yahoo.com/ => Yahoo India
http://philotheoristic.tumblr.com/ => Philotheoristic
https://in.movies.yahoo.com/ => Yahoo India Movies - Bollywood News, Movie Reviews & Hindi Movie Videos
這裏是代碼
public class TitleExtractor {
/* the CASE_INSENSITIVE flag accounts for
* sites that use uppercase title tags.
* the DOTALL flag accounts for sites that have
* line feeds in the title text */
private static final Pattern TITLE_TAG =
Pattern.compile("\\<title>(.*)\\</title>", Pattern.CASE_INSENSITIVE|Pattern.DOTALL);
/**
* @param url the HTML page
* @return title text (null if document isn't HTML or lacks a title tag)
* @throws IOException
*/
public static String getPageTitle(String url) throws IOException {
URL u = new URL(url);
URLConnection conn = u.openConnection();
// ContentType is an inner class defined below
ContentType contentType = getContentTypeHeader(conn);
if (!contentType.contentType.equals("text/html"))
return null; // don't continue if not HTML
else {
// determine the charset, or use the default
Charset charset = getCharset(contentType);
if (charset == null)
charset = Charset.defaultCharset();
// read the response body, using BufferedReader for performance
InputStream in = conn.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(in, charset));
int n = 0, totalRead = 0;
char[] buf = new char[1024];
StringBuilder content = new StringBuilder();
// read until EOF or first 8192 characters
while (totalRead < 8192 && (n = reader.read(buf, 0, buf.length)) != -1) {
content.append(buf, 0, n);
totalRead += n;
}
reader.close();
// extract the title
Matcher matcher = TITLE_TAG.matcher(content);
if (matcher.find()) {
/* replace any occurrences of whitespace (which may
* include line feeds and other uglies) as well
* as HTML brackets with a space */
return matcher.group(1).replaceAll("[\\s\\<>]+", " ").trim();
}
else
return null;
}
}
/**
* Loops through response headers until Content-Type is found.
* @param conn
* @return ContentType object representing the value of
* the Content-Type header
*/
private static ContentType getContentTypeHeader(URLConnection conn) {
int i = 0;
boolean moreHeaders = true;
do {
String headerName = conn.getHeaderFieldKey(i);
String headerValue = conn.getHeaderField(i);
if (headerName != null && headerName.equals("Content-Type"))
return new ContentType(headerValue);
i++;
moreHeaders = headerName != null || headerValue != null;
}
while (moreHeaders);
return null;
}
private static Charset getCharset(ContentType contentType) {
if (contentType != null && contentType.charsetName != null && Charset.isSupported(contentType.charsetName))
return Charset.forName(contentType.charsetName);
else
return null;
}
/**
* Class holds the content type and charset (if present)
*/
private static final class ContentType {
private static final Pattern CHARSET_HEADER = Pattern.compile("charset=([-_a-zA-Z0-9]+)", Pattern.CASE_INSENSITIVE|Pattern.DOTALL);
private String contentType;
private String charsetName;
private ContentType(String headerValue) {
if (headerValue == null)
throw new IllegalArgumentException("ContentType must be constructed with a not-null headerValue");
int n = headerValue.indexOf(";");
if (n != -1) {
contentType = headerValue.substring(0, n);
Matcher matcher = CHARSET_HEADER.matcher(headerValue);
if (matcher.find())
charsetName = matcher.group(1);
}
else
contentType = headerValue;
}
}
}
利用這一類的很簡單：
String title = TitleExtractor.getPageTitle("http://en.wikipedia.org/");
System.out.println(title);
這裏是鏈接：
我希望它是 幫你。
你不知道什麼關於字符串解析或正則表達式嗎？ –