J2EE中使用Filter过滤器清除网页缓存

package www.csdn.dbshop.filter;
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;
import javax.servlet.http.HttpServletResponse;


public class CacheFilter implements Filter 
{
	public void init(FilterConfig filterConfig) throws ServletException 
	{
		System.out.println("初始化");
	}

	public void doFilter(ServletRequest request, ServletResponse response,FilterChain chain) throws IOException, ServletException 
	{
		// response对象
		HttpServletResponse res = (HttpServletResponse) response;
		
		// 设定网页的到期时间，一旦过期则必须到服务器上重新调用
		res.setDateHeader("Expires", -1);
		
		// Cache-Control 指定请求和响应应遵循的缓存机制 no-cache指示请求或响应消息是不能缓存的
		res.setHeader("Cache-Control", "no-cache");
		
		// 用于设定禁止浏览器从本地缓存中调用页面内容，设定后一旦离开页面就无法从Cache中再调出
		res.setHeader("Pragma", "no-cache");
		
		// 放行
		chain.doFilter(request, res);
	}

	public void destroy() 
	{
		System.out.println("销毁");
	}
}