javaWeb--(4)servletConfig

servletConfig，它封裝了servlet的配置信息，經過它能夠獲取到servletContext對象。
配置信息以下

<!-- 配置映射 -->
  <servlet>
  		<servlet-name>helloServlet</servlet-name>
  		<servlet-class>com.test.javaweb.HelloServlet</servlet-class>
  		<!-- 配置servlet的初始化參數 -->
  		<init-param>
  			<param-name>user</param-name>
  			<param-value>root</param-value>
  		</init-param>
  		<init-param>
  			<param-name>password</param-name>
  			<param-value>123456</param-value>
  		</init-param>
  		<load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
  		<servlet-name>helloServlet</servlet-name>
  		<url-pattern>/hello</url-pattern>
  </servlet-mapping>

獲取初始化參數有兩種方法
1.getInitParameter(String name)：獲取指定參數名的初始化參數
2.getInitParameterNames()：獲取全部的參數名

public void init(ServletConfig arg0) throws ServletException {
		// TODO Auto-generated method stub
		System.out.println("init");
		//1.獲取指定參數名的初始化參數
		String user = arg0.getInitParameter("user");
		System.out.println(user);
		//2.獲取全部的參數名及其參數值
		Enumeration<String> names = arg0.getInitParameterNames();
		while (names.hasMoreElements()) {
			String name = (String) names.nextElement();
			//這裏能夠獲取參數值
			String value = arg0.getInitParameter(name);
			System.out.println(name+":"+value);
		}
	}