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