ServletWeb缓存解决问题

（1）为什么我们要防止这个问题的浏览器页面缓存：

所以在不须要缓存的页面中须要实现不缓存页面。

代码例如以下：

package com.lc.HttpTest;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class CacheJiejue extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		response.setContentType("text/html;charset=utf-8");
		//指定该页面不缓存
		response.setDateHeader("Expires",-1); //IE游览器支持的
		
		//保证兼容性
		response.setHeader("Cache-Control", "no-cache");
		response.setHeader("Pragme", "no-cache");
		
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		this.doGet(request, response);
	}

}

（2）可是假设要实现特定时间内的页面缓存则代码例如以下：

package com.lc.HttpTest;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class CacheJiejue extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		response.setContentType("text/html;charset=utf-8");
		//指定该页面不缓存
		//response.setDateHeader("Expires",-1); //IE游览器支持的
		
		//缓存一定的时间  缓存 一天的时间
		response.setDateHeader("Expires",System.currentTimeMillis()+3600*1000*24); 
		//保证兼容性
		response.setHeader("Cache-Control", "no-cache");
		response.setHeader("Pragme", "no-cache");
		
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		this.doGet(request, response);
	}

}