properties属性文件就是key-value
1: 创建对象 Properties pop=new Properties();
2：加载输入流 pop.load(new FileRead(pop文件path))；
3：获取属性 pop.getProperty(key);
Servlet 对象
参数：获取设置 作用域 生命周期
ServletConfig 常用函数：getInitParamer(key);
ServletContext getInitParamer() getAttribute() setAttribute()
路径获取 ServletContext getRealPath();
<!-- 配置运行 部署 -->
<servlet>
<servlet-name>MyFirstServlet</servlet-name>
<servlet-class>my.servlet.FirstServlet</servlet-class>
<init-param> <!-- ServletConfig 对象可以获取到 -->
<description>用户账号</description>
<param-name>user</param-name>
<param-value>admin</param-value>
</init-param>
<init-param> <!-- ServletConfig 对象可以获取到 -->
<description>用户密码</description>
<param-name>psw</param-name>
<param-value>123</param-value>
</init-param>
<!-- 正整数 Tomcat启动时创建 数越小 优先级越高 负数 请求时创建 -->
<load-on-startup>-1</load-on-startup>
</servlet>
<!-- 映射 路径-->
<servlet-mapping>
<servlet-name>MyFirstServlet</servlet-name>
<url-pattern>/aafistPage</url-pattern>
</servlet-mapping>
<context-param> <!-- ServletContext对象获取参数 -->
<param-name>admin</param-name>
<param-value>超级管理员</param-value>
</context-param>
servlet/jsp 中文乱码
1： request.setCharacterEncoding("utf-8");
URLEncoder.encode("str"，"utf-8"); //指定编码
URLDecoder.decode("str"，"utf-8"); //解析编码
ajax.get();
2: response.setCharacterEncoding("utf-8");
response.setContentType("text/html;chartset=utf-8");
html：<meta charset="UTF-8">
jsp:
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<meta charset="UTF-8">