JSP 初始化参数：
tomcat启动的时候就会执行那个函数；
xml：
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID"
version="3.0">
<display-name>TestBootWeb</display-name>
<servlet>
<servlet-name>index007</servlet-name>
<jsp-file>/index007.jsp</jsp-file>
<init-param>
<param-name>email</param-name>
<param-value>s@s.com</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>index007</servlet-name>
<url-pattern>/index007.jsp</url-pattern>
<!-- 写成/index007.jsp的话，竟然index007.jsp和index0071.jsp都可以访问，而且是两个实例，但是获取初始化参数的时候有问题 -->
</servlet-mapping>
<jsp-config>
<jsp-property-group>
<url-pattern>/index006.jsp</url-pattern>
<scripting-invalid>true</scripting-invalid>
</jsp-property-group>
</jsp-config>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
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>
<html>
<head>
<meta charset="UTF-8">
<title>007index</title>
</head>
<body>
cnt is :<%=++cnt%>
<hr>
<%!int cnt = 0;%>
<%!
public void jspInit(){
ServletConfig config = getServletConfig();
String s = config.getInitParameter("email");
System.out.println("s is :"+s);
}
%>
</body>
</html>
生成的java：
/*
* Generated by the Jasper component of Apache Tomcat
* Version: Apache Tomcat/7.0.35
* Generated at: 2015-10-20 01:19:21 UTC
* Note: The last modified time of this file was set to
* the last modified time of the source file after
* generation to assist with modification tracking.
*/
package org.apache.jsp;import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.jsp.*;
import java.util.*;public final class index007_jsp extends org.apache.jasper.runtime.HttpJspBase
implements org.apache.jasper.runtime.JspSourceDependent {int cnt = 0; public void jspInit(){
ServletConfig config = getServletConfig();
String s = config.getInitParameter("email");
System.out.println("s is :"+s);
} 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 javax.el.ExpressionFactory _el_expressionfactory;
private org.apache.tomcat.InstanceManager _jsp_instancemanager; public java.util.Map<java.lang.String,java.lang.Long> getDependants() {
return _jspx_dependants;
} public void _jspInit() {
_el_expressionfactory = _jspxFactory.getJspApplicationContext(getServletConfig().getServletContext()).getExpressionFactory();
_jsp_instancemanager = org.apache.jasper.runtime.InstanceManagerFactory.getInstanceManager(getServletConfig());
} 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 { 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('\r');
out.write('\n'); String path = request.getContextPath();
String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort() + path + "/"; out.write("\r\n");
out.write("<!DOCTYPE html>\r\n");
out.write("<html>\r\n");
out.write("<head>\r\n");
out.write("<meta charset=\"UTF-8\">\r\n");
out.write("<title>007index</title>\r\n");
out.write("</head>\r\n");
out.write("<body>\r\n");
out.write("\tcnt is :");
out.print(++cnt);
out.write("\r\n");
out.write("\t<hr>\r\n");
out.write("\t");
out.write('\r');
out.write('\n');
out.write(' ');
out.write("\r\n");
out.write("</body>\r\n");
out.write("</html>\r\n");
} catch (java.lang.Throwable t) {
if (!(t instanceof javax.servlet.jsp.SkipPageException)){
out = _jspx_out;
if (out != null && out.getBufferSize() != 0)
try { 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);
}
}
}
