15.html

写给JSP初级程序员的书

      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">平台那种层次的对变化的适应性。客户采用</SPAN><SPAN 
      lang=EN-US>WINDOWS DNA</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">就会被绑在中间件和操作系统的微软实现上，如果这个实现的功能性、可伸缩性、可用性不尽人意，客户只能怪自己不够走运。如对底层的操作系统和中间件作些修改就会显著影响应用程序。可被选择的硬件也十分有限。这都会极大地延误公司对变化的市场环境做出反应。</SPAN></P>
      <P class=MsoNormal><B style="mso-bidi-font-weight: normal"><SPAN 
      lang=EN-US style="FONT-SIZE: 16pt; mso-bidi-font-size: 10.0pt"><![if !supportEmptyParas]>&nbsp;<![endif]><o:p></o:p></SPAN></B></P>
      <P class=MsoNormal><B style="mso-bidi-font-weight: normal"><SPAN 
      lang=EN-US 
      style="FONT-SIZE: 16pt; mso-bidi-font-size: 10.0pt">4</SPAN></B><B 
      style="mso-bidi-font-weight: normal"><SPAN 
      style="FONT-FAMILY: 宋体; FONT-SIZE: 16pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.0pt">切入市场的时间</SPAN></B><B 
      style="mso-bidi-font-weight: normal"><SPAN lang=EN-US 
      style="FONT-SIZE: 16pt; mso-bidi-font-size: 10.0pt"><o:p></o:p></SPAN></B></P>
      <P class=MsoNormal><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">在今天的市场开发商业方案，数月时间已经是很漫长的概念，错失一个很小的首先切入市场的机会都会意味着你的公司要花费数年的时间去追赶。</SPAN></P>
      <P class=MsoNormal><SPAN lang=EN-US><![if !supportEmptyParas]>&nbsp;<![endif]><o:p></o:p></SPAN></P>
      <P class=MsoNormal><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">缩短切入市场时间的一种方法就是选择便于应用程序快速开发的服务器端平台。</SPAN><SPAN 
      lang=EN-US>J2EE</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">和</SPAN><SPAN 
      lang=EN-US>WINDOWS DNA</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">都允许公司把一些通用的、很繁琐的服务端任务交给中间件供应商去完成。这样开发人员可以集中精力</SPAN><SPAN 
      lang=EN-US><SPAN style="mso-tab-count: 1">&nbsp;&nbsp;&nbsp; 
      </SPAN></SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">在如何创建商业逻辑上，相应地缩短了开发时间。</SPAN></P>
      <P class=MsoNormal><SPAN lang=EN-US><![if !supportEmptyParas]>&nbsp;<![endif]><o:p></o:p></SPAN></P>
      <P class=MsoNormal><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">然而基于</SPAN><SPAN 
      lang=EN-US>J2EE</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">平台的高级产品比</SPAN><SPAN 
      lang=EN-US>WINDOWS DNA </SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">提供了更大范围的中间件服务。这种有点有些来自于</SPAN><SPAN 
      lang=EN-US>J2EE</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">平台结构本身的优势，一些是由于</SPAN><SPAN 
      lang=EN-US>J2EE</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">能让供应商鲜明地提供各种不同特性而同时保持与平台的兼容性。以下这些复杂的中间件服务是高级中间件供应商所提供的，而在</SPAN><SPAN 
      lang=EN-US>WINDOWS DNA </SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">中却不具备的：</SPAN></P>
      <P class=MsoNormal><B style="mso-bidi-font-weight: normal"><SPAN 
      lang=EN-US style="mso-fareast-font-family: 楷体_GB2312"><![if !supportEmptyParas]>&nbsp;<![endif]><o:p></o:p></SPAN></B></P>
      <P class=MsoNormal><B style="mso-bidi-font-weight: normal"><SPAN 
      style="FONT-FAMILY: 楷体_GB2312; mso-ascii-font-family: 'Times New Roman'">状态管理服务：</SPAN></B><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">可以让开发人员写更少的代码，不用关心如何管理状态，这样能够更快地完成程序开发。</SPAN></P>
      <P class=MsoNormal><B style="mso-bidi-font-weight: normal"><SPAN 
      style="FONT-FAMILY: 楷体_GB2312; mso-ascii-font-family: 'Times New Roman'">持续性服务：</SPAN></B><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">可以让开发人员不用对数据访问逻辑进行编码就能编写应用程序，能生成更轻巧，与数据库无关的应用程序，这种应用程序更易于开发与维护。</SPAN></P>
      <P class=MsoNormal><B style="mso-bidi-font-weight: normal"><SPAN 
      style="FONT-FAMILY: 楷体_GB2312; mso-ascii-font-family: 'Times New Roman'">分布式共享数据对象</SPAN></B><B 
      style="mso-bidi-font-weight: normal"><SPAN lang=EN-US 
      style="mso-fareast-font-family: 楷体_GB2312">CACHE</SPAN></B><B 
      style="mso-bidi-font-weight: normal"><SPAN 
      style="FONT-FAMILY: 楷体_GB2312; mso-ascii-font-family: 'Times New Roman'">服务：</SPAN></B><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">可以让开发人员编制高性能的系统，极大地提高整体部署的伸缩性。</SPAN></P>
      <P class=MsoNormal><SPAN lang=EN-US><![if !supportEmptyParas]>&nbsp;<![endif]><o:p></o:p></SPAN></P>
      <P class=MsoNormal><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">公司选择基于</SPAN><SPAN 
      lang=EN-US>J2EE</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">平台实现以上服务的产品，可比选用基于</SPAN><SPAN 
      lang=EN-US>WINDOWS DNA</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">方案</SPAN> 
      <SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">能更快地切入市场，实现更高水准的伸缩性能。</SPAN></P>
      <P align=left class=MsoNormal 
      style="TEXT-ALIGN: left; mso-layout-grid-align: none"><SPAN lang=EN-US><![if !supportEmptyParas]>&nbsp;<![endif]><o:p></o:p></SPAN></P>
      <P align=left class=MsoNormal 
      style="TEXT-ALIGN: left; mso-layout-grid-align: none"><SPAN 
      lang=EN-US>J2EE</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">平台快速切入市场的特性也有益于那些已拥有成型的电子商务软件的供应商，如</SPAN><SPAN 
      lang=EN-US>SAP, Peoplesoft</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">、</SPAN><SPAN 
      lang=EN-US> Trilogy</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">、</SPAN><SPAN 
      lang=EN-US> Oracle</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">、</SPAN><SPAN 
      lang=EN-US> Tradex</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">、</SPAN><SPAN 
      lang=EN-US> EC Cubed</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">、</SPAN><SPAN 
      lang=EN-US> Integral</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">、</SPAN><SPAN 
      lang=EN-US> I-mind </SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">和</SPAN><SPAN 
      lang=EN-US> Intershop</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">。供应商选择</SPAN><SPAN 
      lang=EN-US>J2EE</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">平台能够构造部署到任何客户目标平台的可移植程序，这些目标平台包括</SPAN><SPAN 
      lang=EN-US>WINDOWS</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">、</SPAN><SPAN 
      lang=EN-US>UNIX</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">、其他已有系统，也包括任何基于</SPAN><SPAN 
      lang=EN-US>J2EE</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">平台的产品。供应商选择微软平台只能支持部署在</SPAN><SPAN 
      lang=EN-US>WINDOWS</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">上的一小部分用户。基于</SPAN><SPAN 
      lang=EN-US>J2EE</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的程序是独立于某一特定技术的，如数据库、操作系统或硬件。这对一个拥有广泛的异构环境下客户的供应商是必需的。</SPAN><SPAN 
      lang=EN-US>J2EE</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">比</SPAN><SPAN 
      lang=EN-US>WINDOWS DNA </SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">提供更多地底层平台服务，有助于软件供应商更快地程序开发，更迅速地市场切入。</SPAN></P>
      <P class=MsoNormal><B style="mso-bidi-font-weight: normal"><SPAN 
      lang=EN-US style="FONT-SIZE: 16pt; mso-bidi-font-size: 10.0pt"><![if !supportEmptyParas]>&nbsp;<![endif]><o:p></o:p></SPAN></B></P>
      <P class=MsoNormal><B style="mso-bidi-font-weight: normal"><SPAN 
      lang=EN-US 
      style="FONT-SIZE: 16pt; mso-bidi-font-size: 10.0pt">5</SPAN></B><B 
      style="mso-bidi-font-weight: normal"><SPAN 
      style="FONT-FAMILY: 宋体; FONT-SIZE: 16pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-size: 10.0pt">平台的成熟性</SPAN></B><B 
      style="mso-bidi-font-weight: normal"><SPAN lang=EN-US 
      style="FONT-SIZE: 16pt; mso-bidi-font-size: 10.0pt"><o:p></o:p></SPAN></B></P>
      <P class=MsoNormal><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">自从</SPAN><SPAN 
      lang=EN-US>1996</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">年</SPAN><SPAN 
      lang=EN-US>12</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">月</SPAN><SPAN 
      lang=EN-US>MTS</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">发布以来，</SPAN><SPAN 
      lang=EN-US>WINDOWS DNA,COM+</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的服务器端构件服务被不断发展，而</SPAN><SPAN 
      lang=EN-US>J2EE</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">、</SPAN><SPAN 
      lang=EN-US>EJB</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">产品则是从</SPAN><SPAN 
      lang=EN-US>1998</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">年开始的。</SPAN></P>
      <P class=MsoNormal><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">看起来好像</SPAN><SPAN 
      lang=EN-US>WINDOWS DNA </SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">是一个成熟的平台。然而事实上，现在基于</SPAN><SPAN 
      lang=EN-US>J2EE</SPAN><SPAN 
      style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">平台的高端产品包含一些重要的事务逻辑，而这些事务逻辑应用在产品中许多年了。提供</SPAN><SPAN 
      lang=EN-US>J2EE</SPAN><SPAN