文章出自:http://babyjoycry.javaeye.com/blog/587527 在此感谢原作者...\(^o^)/~
 
最近研究抓取网页内容,发现要获取页面的编码格式,Java没有现成的实现方法,虽然csdn上有个达人写了一篇文章,附有代码,可惜,我没有找到相关的包,不得已,只好自己动手丰衣足食了。
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;

import cpdetector.io.CodepageDetectorProxy;
import cpdetector.io.HTMLCodepageDetector;
import cpdetector.io.JChardetFacade;

public class PageEncodeDetector {
  private static CodepageDetectorProxy detector = CodepageDetectorProxy
      .getInstance();

  static {
    detector.add(new HTMLCodepageDetector(false));
    detector.add(JChardetFacade.getInstance());
  }

  /**
    * 测试用例
    *    
    * @param args
    */

  public static void main(String[] args) {
    PageEncodeDetector web = new PageEncodeDetector();
    try {
      System.out.println(web.getCharset("http://www.baidu.com/"));
    } catch (IOException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
  }

  /**
    * @param strurl
    *                        页面url地址,需要以 http://开始,例:http://www.pujia.com
    * @return
    * @throws IOException
    */

  public String getCharset(String strurl) throws IOException {
    // 定义URL对象
    URL url = new URL(strurl);
    // 获取http连接对象
    HttpURLConnection urlConnection = (HttpURLConnection) url
        .openConnection();
    ;
    urlConnection.connect();
    // 网页编码
    String strencoding = null;

    /**
     * 首先根据header信息,判断页面编码
     */

    // map存放的是header信息(url页面的头信息)
    Map<String, List<String>> map = urlConnection.getHeaderFields();
    Set<String> keys = map.keySet();
    Iterator<String> iterator = keys.iterator();

    // 遍历,查找字符编码
    String key = null;
    String tmp = null;
    while (iterator.hasNext()) {
      key = iterator.next();
      tmp = map.get(key).toString().toLowerCase();
      // 获取content-type charset
      if (key != null && key.equals("Content-Type")) {
        int m = tmp.indexOf("charset=");
        if (m != -1) {
          strencoding = tmp.substring(m + 8).replace("]", "");
          return strencoding;
        }
      }
    }

    /**
     * 通过解析meta得到网页编码
     */

    // 获取网页源码(英文字符和数字不会乱码,所以可以得到正确<meta/>区域)
    StringBuffer sb = new StringBuffer();
    String line;
    try {
      BufferedReader in = new BufferedReader(new InputStreamReader(url
          .openStream()));
      while ((line = in.readLine()) != null) {
        sb.append(line);
      }
      in.close();
    } catch (Exception e) { // Report any errors that arise
      System.err.println(e);
      System.err
          .println("Usage:     java     HttpClient     <URL>     [<filename>]");
    }
    String htmlcode = sb.toString();
    // 解析html源码,取出<meta />区域,并取出charset
    String strbegin = "<meta";
    String strend = ">";
    String strtmp;
    int begin = htmlcode.indexOf(strbegin);
    int end = -1;
    int inttmp;
    while (begin > -1) {
      end = htmlcode.substring(begin).indexOf(strend);
      if (begin > -1 && end > -1) {
        strtmp = htmlcode.substring(begin, begin + end).toLowerCase();
        inttmp = strtmp.indexOf("charset");
        if (inttmp > -1) {
          strencoding = strtmp.substring(inttmp + 7, end).replace(
              "=", "").replace("/", "").replace("\"", "")
              .replace("\'", "").replace(" ", "");
          return strencoding;
        }
      }
      htmlcode = htmlcode.substring(begin);
      begin = htmlcode.indexOf(strbegin);
    }

    /**
     * 分析字节得到网页编码
     */

    strencoding = getFileEncoding(url);

    // 设置默认网页字符编码
    if (strencoding == null) {
      strencoding = "GBK";
    }

    return strencoding;
  }

  /**
    *    
    *<br>
    * 方法说明:通过网页内容识别网页编码
    *    
    *<br>
    * 输入参数:strUrl 网页链接; timeout 超时设置
    *    
    *<br>
    * 返回类型:网页编码
    */

  public static String getFileEncoding(URL url) {

    java.nio.charset.Charset charset = null;
    try {
      charset = detector.detectCodepage(url);
    } catch (Exception e) {
      System.out.println(e.getClass() + "分析" + "编码失败");
    }
    if (charset != null)
      return charset.name();
    return null;

  }

}
 
需要下载cpdetector_1.0.5.jar 和 chardet.jar