Java实现抓取HTTP头部信息

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class WebClient{
 public static String  getWebContent(String urlString,final String charset,int timeout) throws IOException {
  if(urlString==null||urlString.length()==0) {
   return null;
  }
  urlString = (urlString.startsWith("http://") || urlString
    .startsWith("https://")) ? urlString : ("http://" + urlString)
    .intern();
  URL url = new URL(urlString);
  HttpURLConnection conn = (HttpURLConnection) url.openConnection();
  conn
    .setRequestProperty(
      "User-Agent",
      "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; Trident/4.0; .NET CLR 1.1.4322; .NET CLR 2.0.50727)");//增加报头，模拟浏览器，防止屏蔽
  conn.setRequestProperty("Accept", "text/html");//只接受text/html类型，当然也可以接受图片,pdf,*/*任意，就是tomcat/conf/web里面定义那些
  conn.setConnectTimeout(timeout);
  try {
   if(conn.getResponseCode()!=HttpURLConnection.HTTP_OK) {
    return null;
   }
  } catch (IOException e) {
   e.printStackTrace();
   return null;