Servlet xml文件传参

xml文件可以直接传键值对到servlet代码中：

脱离servlet标签外，代表全局的键值对，key=global，value=value，这样xml文件中所有的servlet都可以访问这个参数。

  <context-param>  <!-- 全局参数 -->
    <param-name>global</param-name>
    <param-value>value</param-value>
  </context-param>

处于servlet标签中， 表示只有该servlet才能访问。

<servlet>
    <servlet-name>ConfigServlet</servlet-name>
    <servlet-class>ch02.ConfigServlet</servlet-class>
    <init-param>
      <param-name>date</param-name>
      <param-value>202030</param-value>
    </init-param>
    <init-param>
      <param-name>browser</param-name>
      <param-value>google</param-value>
    </init-param>
</servlet>
<servlet-mapping>
    <servlet-name>ConfigServlet</servlet-name>
    <url-pattern>/config</url-pattern>
</servlet-mapping>

       /**
	 * @see Servlet#init(ServletConfig)
	 */
public void init(ServletConfig config) throws ServletException {		
		String parameter1 = config.getInitParameter("date");
		String parameter2 = config.getInitParameter("browser");
		System.out.println(parameter1 + " " + parameter2);
	}


	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {		
		String global = getServletContext().getInitParameter("global"); // 访问全局参数
		response.getWriter().append(con);		
	}

要注意访问全局的参数和局部的参数方法名是不同的：

局部getServletConfig().getInitParameter、全局getServletContext(). getInitParameter