webpage.java

来自「一个使用的搜索引擎」· Java 代码 · 共 84 行

package ir.webutils;
/*
 * WebPage.java
 * utility class to handle downloading web pages.
 * May 23, 2001
 * Ted Wild
 */


import java.net.*;
import java.io.*;

/**
 * WebPage is a static utility class that provides operations for
 * downloading web pages.
 *
 * @author Ted Wild */
public class WebPage {

    /**
     * Downloads the web page specified by the URL represented by a
     * given string.
     *
     * @param urlString <code>String</code> representation of the URL
     * to get the page from.  The URL must be absolute.
     *
     * @return A <code>String</code> containing the contents of the
     * page.  No extra parsing work is done on the page.  */
    public static String getWebPage(String urlString) {
	String page = null;
	try {
	    URL url = URLChecker.getURL(urlString);
	    page = getWebPage(url);	
	}
	catch (MalformedURLException e) {
	    System.out.println("WebPage.getWebPage(): " + e.toString());
	}
	return page;
    }

    /**
     * Downloads the web page specified by the given <code>URL</code>
     * object.
     *
     * @param url The <code>URL</code> object that the page will be
     * downloaded from.
     *
     * @return A <code>String</code> containing the contents of the
     * page.  No extra parsing work is done on the page.  */
    public static String getWebPage(URL url) {

	// using a StringBuffer instead of a String has huge
	// performance benefits.
	StringBuffer page = new StringBuffer(); 

	try {
	    URLConnection connection = url.openConnection();
	    String line;
	    BufferedReader in;
	    if (connection.getContentEncoding() == null)
		in = new BufferedReader(new InputStreamReader(url.openStream()));
	    else 
		in = new BufferedReader(new InputStreamReader(url.openStream(), 
							      connection.getContentEncoding()));
	    while ((line = in.readLine()) != null)
		page.append(line).append('\n');

	    in.close();
	}
	catch (UnsupportedEncodingException e) {
	    System.err.println("WebPage.getWebPage(): " + e);
	}
	catch (IOException e) {
	    System.err.println("WebPage.getWebPage(): " + e);
	}

	return page.toString();
    }

    public static void main(String[] args) {
	getWebPage(args[0]);
    }
}