如何处理java高并发问题---之页面静态化

解决java中的高并发问题可以从硬件软件等方面入手，硬件如：服务器；软件如：系统缓存、页面静态化等。这里我写的是页面静态化的简单小例子。之所以将这个小例子记录下来是因为之前对页面静态化有误解，原以为静态化页面就是在项目编写中前端页面利用html就可以。但是在参考网上资料后发现理解误差很大，以下是我在参考了一些网上资料后写的实现页面静态化的简单实例：

项目结构图

1.业务处理类Servlet.java（这里为了方便采用的servlet，可根据项目需求在其他的架构中使用其中的业务逻辑）

 package com.servlet;

 import java.io.File;
 import java.io.IOException;

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

 public class Servlet extends HttpServlet{

     public void service(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException{
         System.out.println("chapterId=====//===="+request.getParameter("chapterId"));
         if(request.getParameter("chapterId")!= null){
             String chapterFileName = "bookChapterRead_"+request.getParameter("chapterId")+".html";
             String chapterFilePath = getServletContext().getRealPath("/") + chapterFileName;
             System.out.println("chapterFilePath===//============="+chapterFilePath);
             File chapterFile = new File(chapterFilePath);
             System.out.println("chapterFile===//============="+chapterFile);
             if(chapterFile.exists()){//如果有这个文件就告诉浏览器转向
                 System.out.println("有此静态页面＝＝＝＝＝＝");
                 response.sendRedirect(chapterFileName);
                 return;
               }
             System.out.println("没有此静态页面＝＝＝＝＝＝");
             //======存放业务处理后得到的信息
             request.setAttribute("novelChapter", "测试单节信息");
             request.setAttribute("lastPageId", "lastPageId111");
             request.setAttribute("nextPageId", "nextPageId222");
             //============
             System.out.println("getServletContext()==========//========="+getServletContext());
             new CreateStaticHTMLPage().createStaticHTMLPage(request, response, getServletContext(),
                     chapterFileName, chapterFilePath, "/bookRead.jsp");
         }

     }

 }

２.创建静态页面类CreateStaticHTMLPage.java

 package com.servlet;

 import java.io.ByteArrayOutputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.OutputStreamWriter;
 import java.io.PrintWriter;

 import javax.servlet.RequestDispatcher;
 import javax.servlet.ServletContext;
 import javax.servlet.ServletException;
 import javax.servlet.ServletOutputStream;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import javax.servlet.http.HttpServletResponseWrapper;

 /**
 * 创建HTML静态页面
 * 功能：创建HTML静态页面
 */
 public class CreateStaticHTMLPage {
      /**
      * 生成静态HTML页面的方法
      * @param request 请求对象
      * @param response 响应对象
      * @param servletContext Servlet上下文
      * @param fileName 文件名称
      * @param fileFullPath 文件完整路径
      * @param jspPath 需要生成静态文件的JSP路径(相对即可)
      * @throws IOException
      * @throws ServletException
      */
     public void createStaticHTMLPage(HttpServletRequest request, HttpServletResponse response,ServletContext servletContext,String fileName,String fileFullPath,String jspPath) throws ServletException, IOException{
         response.setContentType("text/html;charset=utf-8");//设置HTML结果流编码(即HTML文件编码)
         RequestDispatcher rd = servletContext.getRequestDispatcher(jspPath);//得到JSP资源
         final ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();//用于从ServletOutputStream中接收资源
         final ServletOutputStream servletOuputStream = new ServletOutputStream(){//用于从HttpServletResponse中接收资源
             public void write(byte[] b, int off,int len){
                 byteArrayOutputStream.write(b, off, len);
             }
             public void write(int b){
                 byteArrayOutputStream.write(b);
             }
         };
         final PrintWriter printWriter = new PrintWriter(new OutputStreamWriter(byteArrayOutputStream));//把转换字节流转换成字符流
         HttpServletResponse httpServletResponse = new HttpServletResponseWrapper(response){//用于从response获取结果流资源(重写了两个方法)
             public ServletOutputStream getOutputStream(){
                 return servletOuputStream;
             }
             public PrintWriter getWriter(){
                 return printWriter;
             }
         };
         rd.include(request, httpServletResponse);//发送结果流
         printWriter.flush();//刷新缓冲区，把缓冲区的数据输出
         FileOutputStream fileOutputStream = new FileOutputStream(fileFullPath);
         byteArrayOutputStream.writeTo(fileOutputStream);//把byteArrayOuputStream中的资源全部写入到fileOuputStream中
         fileOutputStream.close();//关闭输出流，并释放相关资源
         response.sendRedirect(fileName);//发送指定文件流到客户端
     }

 }

３.web.xml配置文件

 <?xml version="1.0" encoding="UTF-8"?>
 <web-app version="2.5"
     xmlns="http://java.sun.com/xml/ns/javaee"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
     http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">

     <servlet>
       <servlet-name>htmlServlet</servlet-name>
       <servlet-class>com.servlet.Servlet</servlet-class>
     </servlet>
     <servlet-mapping>
       <servlet-name>htmlServlet</servlet-name>
       <url-pattern>*.do</url-pattern>
     </servlet-mapping>

   <welcome-file-list>
     <welcome-file>index.jsp</welcome-file>
   </welcome-file-list>
 </web-app>

４.首页面index.jsp

 <%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
 <%
 String path = request.getContextPath();
 String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
 %>
 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
 <html>
   <head>
     <base href="<%=basePath%>">

     <title>首页面</title>
     <meta http-equiv="pragma" content="no-cache">
     <meta http-equiv="cache-control" content="no-cache">
     <meta http-equiv="expires" content="0">
     <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
     <meta http-equiv="description" content="This is my page">
     <!--
     <link rel="stylesheet" type="text/css" href="styles.css">
     -->
   </head>

   <body>
    <form action="kanName.do">
      <input name="chapterId" type="text" value="122"/>
      <input name="userName" type="text" value="张庆伟"/>
      <input type="submit" value="提交"/>
    </form>
   </body>
 </html>

5.跳转后的结果页面bookRead.jsp

 <%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
 <%
 String path = request.getContextPath();
 String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
 %>
 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
 <html>
   <head>
   <%
     String lastPageId=(String)request.getAttribute("lastPageId");
   %>
     <base href="<%=basePath%>">

     <title>book页</title>
     <meta http-equiv="pragma" content="no-cache">
     <meta http-equiv="cache-control" content="no-cache">
     <meta http-equiv="expires" content="0">
     <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
     <meta http-equiv="description" content="This is my page">
     <!--
     <link rel="stylesheet" type="text/css" href="styles.css">
     -->
   </head>

   <body>
   这是跳转页面：
    <%=lastPageId %>
   </body>
 </html>

以上代码是实例的所有代码，启动项目后点击提交按钮后，会看到跳转到一个html页面。

以上代码参考自：http://blog.csdn.net/jimmy609/article/details/37810591