讀取web.xml參數

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
  <servlet>
    <servlet-name>firstServlet</servlet-name>
    <servlet-class>com.unei.service.FirstServlet</servlet-class>
    <init-param>
    	<param-name>name</param-name>
    	<param-value>user</param-value>
    </init-param>
    
    <init-param>
    	<param-name>pwd</param-name>
    	<param-value>test</param-value>
    </init-param>
  </servlet>
  <servlet-mapping>
    <servlet-name>firstServlet</servlet-name>
    <url-pattern>/first</url-pattern>
  </servlet-mapping>
  
  <context-param>
  	<param-name>uploadfolder</param-name>
  	<param-value>attach</param-value>
  </context-param>
  
  <env-entry>
  	<env-entry-name>hello</env-entry-name>
  	<env-entry-type>java.lang.String</env-entry-type>
  	<env-entry-value>Hello,Welcome to java</env-entry-value>
  </env-entry>
</web-app>

java

public class FirstServlet extends HttpServlet{

	//資源注射(@Resource)
	@Resource(name="hello")
	private String hello;
	
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		//servlet初始化參數（init-param）
		System.out.println(getInitParameter("name"));
		System.out.println(getInitParameter("pwd"));
		System.out.println(hello);
		
		//上下文參數（context-param）
		ServletContext sc=getServletConfig().getServletContext();
		String uploadFolder=sc.getInitParameter("uploadfolder");
		System.out.println(uploadFolder);
		
		//JNDI讀取數據
		try {
			Context ctx=new InitialContext();
			String message=(String)ctx.lookup("java:comp/env/hello");
			System.out.println(message);
		} catch (NamingException e) {
			e.printStackTrace();
		}
	}

}