simplefilter1.java

《精通JSP编程 》源代码(赵强那本) 很有用的源代码

package edu.j2ee.servletfilter;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

import java.io.IOException;
import javax.servlet.ServletException;

public class SimpleFilter1 implements Filter
{
  private FilterConfig filterConfig;
 
	 /**
     *初始化过滤器,和一般的Servlet一样，它也可以获得初始参数。
     */
    public void init(FilterConfig config) throws ServletException {
        this.filterConfig = config;       
    }
  public void doFilter (ServletRequest request,
             ServletResponse response,
             FilterChain chain)
  {

    try
    {
     
      System.out.println ("Within SimpleFilter1:Filtering the Request ...");

      chain.doFilter (request, response); // 把处理发送到下一个过滤器

      
      System.out.println ("Within SimpleFilter1: Filtering the Response ...");

    } catch (IOException io) {
      System.out.println ("IOException raised in SimpleFilter");
    } catch (ServletException se) {
      System.out.println ("ServletException raised in SimpleFilter");
    }
  }

 
  //销毁过滤器
	public void destroy()
	{
		this.filterConfig=null;
	}
}