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• Two methods
  • A URL to get the page source code geturlcontentstring, the other one from the source code to get the desired address fragments, which need to use regular expressions to match
• The process of getting the Web source code:
  • address is string, convert address to URL object in Java
  • The OpenConnection method of the URL returns urlconnection
  • URLConnection Connect method to establish a connection
  • Create a new InputStreamReader object , where InputStreamReader's build requires InputStream input stream objects, and URLConnection's getInputStream method returns an input stream object, so you can connect
  • . Span style= "color:black; Font-family: Microsoft Black "> Then use the established InputStreamReader object to establish the Bufferereader object
  • Read the Web page source from the BufferedReader object in line, append to the result string, the result string is the page source code string
• Logo address Matching
  • ? Pattern pattern = pattern.compile (patternstring);
    • Java.util.regex:Java Class library package that matches a string with a pattern defined by a regular expression

      It consists of two classes: pattern and matcher.

      Pattern: Creates a matching pattern string.

      Matcher: Matches the pattern string with the input string.

    • The Compile method of pattern : Compiles the specified characters into the pattern
  • Matcher Matcher = Pattern.matcher (contentstring);

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Package com.test; ?? Import java.io.*; Import java.net.*; Import java.util.regex.*; ?? Public class Baidulogo { ???? static string geturlcontentstring (String urlstring) throws Exception { ???????? String result = ""; ???????? URL url = new URL (urlstring); ???????? URLConnection urlconnection = url.openconnection (); ???????? Urlconnection.connect (); ???????? InputStreamReader inputstreamreader = new inputstreamreader ( ???????????????? Urlconnection.getinputstream (), "Utf-8"); ???????? BufferedReader in = new BufferedReader (inputstreamreader); ???????? String Line; ???????? While (line = in . ReadLine ()) = null) { ???????????? result + = line; ???????? } ???????? return result; ???? } ?? ???? static string Getlogourl (String contentstring, String patternstring) { ???????? String logourl = null; ???????? Pattern pattern = pattern.compile (patternstring); ???????? Matcher Matcher = Pattern.matcher (contentstring); ???????? if (Matcher.find ()) { ???????????? Logourl = Matcher.group (1); ???????? } ???????? return logourl; ?? ???? } ?? ???? Public staticvoid main (string[] args) throws Exception { ???????? // define the link that will be visited ???????? String urlstring = "http://www.baidu.com"; ???????? String result = geturlcontentstring (urlstring); ???????? String patternstring = "Src=\" (. +?) \""; ???????? String contentstring = result; ???????? String Logourl = Getlogourl (contentstring, patternstring); ???????? System.out.println (logourl); ???? } }

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