javaWeb--(4)servletConfig

servletConfig，它封装了servlet的配置信息，经过它能够获取到servletContext对象。
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的初始化参数 -->
  		<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>

获取初始化参数有两种方法
1.getInitParameter(String name)：获取指定参数名的初始化参数
2.getInitParameterNames()：获取全部的参数名

public void init(ServletConfig arg0) throws ServletException {
		// TODO Auto-generated method stub
		System.out.println("init");
		//1.获取指定参数名的初始化参数
		String user = arg0.getInitParameter("user");
		System.out.println(user);
		//2.获取全部的参数名及其参数值
		Enumeration<String> names = arg0.getInitParameterNames();
		while (names.hasMoreElements()) {
			String name = (String) names.nextElement();
			//这里能够获取参数值
			String value = arg0.getInitParameter(name);
			System.out.println(name+":"+value);
		}
	}