选中Eclipse里创建的jsp文件：
???test.jsp的源代码：
“`jsp
<%@ page language=”java” contentType=”text/html; charset=UTF-8″
pageEncoding=”UTF-8″%>
<!DOCTYPE html PUBLIC “-//W3C//DTD HTML 4.01 Transitional//EN” “http://www.w3.org/TR/html4/loose.dtd”>
<html>
<head>
<meta http-equiv=”Content-Type” content=”text/html; charset=UTF-8″>
<title>w3cschool教程 2</title>
</head>
<body>
<%
out.println(“Hello World 2!”);
%>
</body>
</html>
“`
点击Run As server：
???在我本机tomcat文件夹的路径work/catalina/localhost下面，自动生成了一个以JSP项目命名的文件夹jerryjsp:
??????打开这个自动被Apache Tomcat Jasper组件生成的test_jsp.java文件：
package org.apache.jsp;import javax.servlet.*;import javax.servlet.http.*;import javax.servlet.jsp.*;public final class test_jsp extends org.apache.jasper.runtime.HttpJspbase ???implements org.apache.jasper.runtime.JspSourceDependent, ????????????????org.apache.jasper.runtime.JspSourceimports { ?private static final javax.servlet.jsp.JspFactory _jspxFactory = ?????????javax.servlet.jsp.JspFactory.getDefaultFactory(); ?private static java.util.Map<java.lang.String,java.lang.Long> _jspx_dependants; ?private static final java.util.Set<java.lang.String> _jspx_imports_packages; ?private static final java.util.Set<java.lang.String> _jspx_imports_classes; ?static { ???_jspx_imports_packages = new java.util.HashSet<>(); ???_jspx_imports_packages.add("javax.servlet"); ???_jspx_imports_packages.add("javax.servlet.http"); ???_jspx_imports_packages.add("javax.servlet.jsp"); ???_jspx_imports_classes = null; ?} ?private volatile javax.el.expressionFactory _el_expressionfactory; ?private volatile org.apache.tomcat.InstanceManager _jsp_instancemanager; ?public java.util.Map<java.lang.String,java.lang.Long> getDependants() { ???return _jspx_dependants; ?} ?public java.util.Set<java.lang.String> getPackageimports() { ???return _jspx_imports_packages; ?} ?public java.util.Set<java.lang.String> getClassimports() { ???return _jspx_imports_classes; ?} ?public javax.el.expressionFactory _jsp_getexpressionFactory() { ???if (_el_expressionfactory == null) { ?????synchronized (this) { ???????if (_el_expressionfactory == null) { ?????????_el_expressionfactory = _jspxFactory.getJspApplicationContext(getServletConfig().getServletContext()).getexpressionFactory(); ???????} ?????} ???} ???return _el_expressionfactory; ?} ?public org.apache.tomcat.InstanceManager _jsp_getInstanceManager() { ???if (_jsp_instancemanager == null) { ?????synchronized (this) { ???????if (_jsp_instancemanager == null) { ?????????_jsp_instancemanager = org.apache.jasper.runtime.InstanceManagerFactory.getInstanceManager(getServletConfig()); ???????} ?????} ???} ???return _jsp_instancemanager; ?} ?public void _jspInit() { ?} ?public void _jspDestroy() { ?} ?public void _jspService(final javax.servlet.http.HttpServletRequest request, final javax.servlet.http.HttpServletResponse response) ?????throws java.io.IOException, javax.servlet.ServletException { ???if (!javax.servlet.DispatcherType.ERROR.equals(request.getDispatcherType())) { ?????final java.lang.String _jspx_method = request.getMethod(); ?????if ("OPTIONS".equals(_jspx_method)) { ???????response.setHeader("Allow","GET, HEAD, POST, OPTIONS"); ???????return; ?????} ?????if (!"GET".equals(_jspx_method) && !"POST".equals(_jspx_method) && !"HEAD".equals(_jspx_method)) { ???????response.setHeader("Allow","GET, HEAD, POST, OPTIONS"); ???????response.sendError(HttpServletResponse.SC_METHOD_NOT_ALLOWED, "JSPs only permit GET, POST or HEAD. Jasper also permits OPTIONS"); ???????return; ?????} ???} ???final javax.servlet.jsp.PageContext pageContext; ???javax.servlet.http.HttpSession session = null; ???final javax.servlet.ServletContext application; ???final javax.servlet.ServletConfig config; ???javax.servlet.jsp.JspWriter out = null; ???final java.lang.Object page = this; ???javax.servlet.jsp.JspWriter _jspx_out = null; ???javax.servlet.jsp.PageContext _jspx_page_context = null; ???try { ?????response.setContentType("text/html; charset=UTF-8"); ?????pageContext = _jspxFactory.getPageContext(this, request, response, ?????null, true, 8192, true); ?????_jspx_page_context = pageContext; ?????application = pageContext.getServletContext(); ?????config = pageContext.getServletConfig(); ?????session = pageContext.getSession(); ?????out = pageContext.getOut(); ?????_jspx_out = out; ?????out.write("n"); ?????out.write("<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">n"); ?????out.write("<html>n"); ?????out.write("<head>n"); ?????out.write("<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">n"); ?????out.write("<title>w3cschool教程 2</title>n"); ?????out.write("</head>n"); ?????out.write("<body>n"); ???out.println("Hello World 2!"); ?????out.write("n"); ?????out.write("</body>n"); ?????out.write("</html>"); ???} catch (java.lang.Throwable t) { ?????if (!(t instanceof javax.servlet.jsp.SkipPageException)){ ???????out = _jspx_out; ???????if (out != null && out.getBufferSize() != 0) ?????????try { ???????????if (response.isCommitted()) { ?????????????out.flush(); ???????????} else { ?????????????out.clearBuffer(); ???????????} ?????????} catch (java.io.IOException e) {} ???????if (_jspx_page_context != null) _jspx_page_context.handlePageException(t); ???????else throw new ServletException(t); ?????} ???} finally { ?????_jspxFactory.releasePageContext(_jspx_page_context); ???} ?}} 终端用户在浏览器里看到的静态页面的源代码：
???是在这个java文件此处被拼接的：
???关于对jsp文件的请求是如何被服务器的JSP容器转换成静态网页并发送给浏览器，可以参考w3c的jsp教程：
https://www.w3cschool.cn/jsp/jsp-architecture.html
网络服务器需要一个JSP引擎，也就是一个容器来处理JSP页面。容器负责截获对JSP页面的请求。本教程使用内嵌JSP容器的Apache来支持JSP开发。
JSP容器与Web服务器协同合作，为JSP的正常运行提供必要的运行环境和其他服务，并且能够正确识别专属于JSP网页的特殊元素。
下图显示了JSP容器和JSP文件在Web应用中所处的位置。
???# JSP处理
以下步骤表明了Web服务器是如何使用JSP来创建网页的：
(1) 就像其他普通的网页一样，浏览器发送一个HTTP请求给服务器。
(2) Web服务器识别出这是一个对JSP网页的请求，并且将该请求传递给JSP引擎。通过使用URL或者.jsp文件来完成。
(3) JSP引擎从磁盘中载入JSP文件，然后将它们转化为servlet。这种转化只是简单地将所有模板文本改用println()语句，并且将所有的JSP元素转化成Java代码。
(4) JSP引擎将servlet编译成可执行类，并且将原始请求传递给servlet引擎。
(5) Web服务器的某组件将会调用servlet引擎，然后载入并执行servlet类。在执行过程中，servlet产生HTML格式的输出并将其内嵌于HTTP response中上交给Web服务器。
(6) Web服务器以静态HTML网页的形式将HTTP response返回到您的浏览器中。
(7) 最终，Web浏览器处理HTTP response中动态产生的HTML网页，就好像在处理静态网页一样。
以上提及到的步骤可以用下图来表示：
???一般情况下，JSP引擎会检查JSP文件对应的servlet是否已经存在，并且检查JSP文件的修改日期是否早于servlet。如果JSP文件的修改日期早于对应的servlet，那么容器就可以确定JSP文件没有被修改过并且servlet有效。这使得整个流程与其他脚本语言（比如PHP）相比要高效快捷一些。
总的来说，JSP网页就是用另一种方式来编写servlet而不用成为Java编程高手。除了解释阶段外，JSP网页几乎可以被当成一个普通的servlet来对待。