JAVAEE Filter 过滤器设置是否缓存实例详解

<span style="font-size:24px;">package cn.hncu.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.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 
public class CacheFilter implements Filter { 
@Override 
public void destroy() { 
}</span> 
<span style="font-size:24px;"> 
@Override 
public void doFilter(ServletRequest request , ServletResponse response, 
FilterChain chain) throws IOException, ServletException { 
// 过滤器有很多作用，这个用来设置客户端是否设置缓存的问题,我们这里采用response通知客户端设置不缓存 
chain.doFilter(request, response); 
HttpServletResponse res=(HttpServletResponse) response; 
res.setHeader("expries", "-1"); 
res.setHeader("pragma", "no-cache"); 
res.setHeader("cache-control", "no-cache"); 
/*上面的已经可以设置不缓存，但是还可以设置全面一点： 
//不允许浏览器端或缓存服务器缓存当前页面信息。 
/* response.setHeader( "Pragma", "no-cache" ); 
response.setDateHeader("Expires", "-1"); 
response.addHeader( "Cache-Control", "no-cache" );//浏览器和缓存服务器都不应该缓存页面信息 
response.addHeader( "Cache-Control", "no-store" );//请求和响应的信息都不应该被存储在对方的磁盘 response.addHeader( "Cache-Control", "must-revalidate" );*///于客户机的每次请求，代理服务器必须想服务器验证缓存是否过时； 
} 
@Override 
public void init(FilterConfig arg0) throws ServletException { 
} 
}</span><span style="font-size:18px;"> 
</span> 

package cn.hncu.filter; 
import java.io.IOException; 
import java.util.Date; 
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 CacheFilter2 implements Filter { 
@Override 
public void destroy() { 
} 
@Override 
public void doFilter(ServletRequest request , ServletResponse response, 
FilterChain chain) throws IOException, ServletException { 
// 过滤器有很多作用，这个用来设置客户端是否设置缓存的问题,我们这里采用response通知客户端设置缓存 
//这里设置缓存1天，以实现让图片、视频类的资源(在过滤器当中配置相应的拦截路径)要求客户浏览器缓存1天) 
//拦截路径在web.xml中配置 
chain.doFilter(request, response);//先进行请求，返回也会从过这里，返回进行拦截 
HttpServletResponse res=(HttpServletResponse) response; 
Date d =new Date(); 
Long time=d.getTime()+60*60*24; 
// res.setHeader("expries", ""+time);//这样就设置缓存一天 
res.setDateHeader("expries", time);//和上面一句一样 
/* 
* Date date = new Date(); 
response.setDateHeader("Last-Modified",date.getTime()); //Last-Modified:页面的最后生成时间 
response.setDateHeader("Expires",date.getTime()+60*60*24); //Expires:过时期限值 
response.setHeader("Cache-Control", "public"); //Cache-Control来控制页面的缓存与否,public:浏览器和缓存服务器都可以缓存页面信息； 
response.setHeader("Pragma", "Pragma"); //Pragma:设置页面是否缓存，为Pragma则缓存，no-cache则不缓存 
*/ 
} 
@Override 
public void init(FilterConfig arg0) throws ServletException { 
}