ServletContext
1.共享数据
//HttpServlet有getServletContext获取ServletContext对象
servletContext.setAttribute("name","陈耀鹏");
//另外的servlet可以调用getAttribute
Object name = context.getAttribute("name");
2.获取初始化参数
<context-param>
<param-name>url</param-name>
<param-value>jdbc</param-value>
</context-param>
String url = context.getInitParameter("url");
System.out.println(url);
3.请求转发
//转发
context.getRequestDispatcher("/hello").forward(req,resp) ;
保证在resources可以识别到文件
<resources>
<resource>
<directory>src/main/resources</directory>
<includes>
<include>**/*.properties</include>
<include>**/*.xml</include>
</includes>
<filtering>true</filtering>
</resource>
</resources>
4.读取资源文件
username=root
password=123456
InputStream stream = context.getResourceAsStream("/WEB-INF/classes/db.properties");
Properties prop = new Properties();
prop.load(stream);
String username = prop.getProperty("username");