在Java编程中，如何读取和下载网页？
以下示例显示如何使用net.URL类的URL()构造函数来读取和下载网页。
package com.yiibai;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.InputStreamReader;
import java.net.URL;
public class DownloadingWebpage {
public static void main(String[] args) throws Exception {
URL url = new URL("http://www.yiibai.com");
BufferedReader reader = new BufferedReader(new InputStreamReader(url.openStream()));
BufferedWriter writer = new BufferedWriter(new FileWriter("save2yiibai-index.html"));
String line;
while ((line = reader.readLine()) != null) {
System.out.println(line);
writer.write(line);
writer.newLine();
}
reader.close();
writer.close();
}
}
上述代码示例将产生以下结果(输出易百教程的首页页面源代码，并保存到save2yiibai-index.html文件中) -
<!--
输出易百教程的首页页面源代码
-->
<!DOCTYPE HTML>
<html>
<head><!--
-->
<!DOCTYPE HTML>
<html>
<head>
... ... 省略
示例-2
Java读取和下载网页的另一个示例：
package com.yiibai;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
public class DownloadingWebpage2 {
public static void main(String[] args) {
URL url;
InputStream is = null;
BufferedReader br;
String line;
try {
url = new URL("http://www.yiibai.com/javaexamples/date_time_month.html");
is = url.openStream(); // throws an IOException
br = new BufferedReader(new InputStreamReader(is));
while ((line = br.readLine()) != null) {
System.out.println(line);
}
} catch (MalformedURLException mue) {
mue.printStackTrace();
} catch (IOException ioe) {
ioe.printStackTrace();
} finally {
try {
if (is != null)
is.close();
} catch (IOException ioe) {
}
}
}
}
上述代码示例将产生以下结果(输出页面源代码) -
<!DOCTYPE HTML>
<html>
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
...... 省略