java 获取网页源代码 （防乱码）

package webcon;
import java.io.BufferedReader;
public class WebCon {
// 获取网页源代码
public String getWebCon(String pageURL,String encoding) {
//
StringBuffer sb =
4000
new StringBuffer();
try {
URL url = new URL(pageURL);
BufferedReader in = new BufferedReader(new InputStreamReader(url
.openStream(),encoding));
String line;
while ((line = in.readLine()) != null) {
sb.append(line);
}
in.close();
} catch (Exception e) { // Report any errors that arise
sb.append(e.toString());
System.err.println(e);
System.err
.println("Usage:   java   HttpClient   <URL>   [<filename>]");
}
return sb.toString();
}
}