import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
public class CharactorFilter implements Filter { //繼承Filter類
  //字元編碼
  String encoding=null;
  public void doFilter(ServletRequest request, ServletResponse response,
          FilterChain chain) throws IOException, ServletException {
      if(encoding!=null){
      //設定request字元編碼
          request.setCharacterEncoding(encoding);
       //設定response字元編碼
          response.setContentType("text/html;charset="+encoding);
      }
   //傳遞給下一個過濾器
      chain.doFilter(request, response);
  }
  public void init(FilterConfig filterConfig) throws ServletException {
    //獲取初始化引數
      encoding=filterConfig.getInitParameter("encoding");
  }
  public void destroy() {
      // TODO Auto-generated method stub
      encoding=null;
  }
}
    //過濾器名
    CharactorFilter
    //類路徑
    com.xx.Util.CharactorFilter
      //引數名稱
      encoding
      //引數值
      utf-8
    過濾器對映
    CharactorFilter
    過濾型別
    /*