A servlet configuration object used by a servlet container to pass information to a servlet during initialization.
servlet 容器使用的 servlet 配置对象,该对象在初始化期间将信息传递给 servlet。
ServletConfig接口提供的方法:
Method Summary | |
---|---|
String |
getInitParameter(String name) Returns a String containing the value of the named initialization parameter, or null if the parameter does not exist. |
Enumeration |
getInitParameterNames() Returns the names of the servlet's initialization parameters as an Enumeration of String objects, or an empty Enumeration if the servlet has no initialization parameters. |
ServletContext |
getServletContext() Returns a reference to the ServletContext in which the caller is executing. |
String |
getServletName() Returns the name of this servlet instance. |
代码演示:
1 package com.itheima.action; 2 3 import java.io.IOException; 4 import java.util.Enumeration; 5 6 import javax.servlet.ServletConfig; 7 import javax.servlet.ServletException; 8 import javax.servlet.http.HttpServlet; 9 import javax.servlet.http.HttpServletRequest; 10 import javax.servlet.http.HttpServletResponse; 11 12 /** 13 * Servlet implementation class ServeletDemo13 14 */ 15 public class ServletDemo13 extends HttpServlet { 16 private static final long serialVersionUID = 1L; 17 18 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 19 // 0.获取ServletConfig对象 20 ServletConfig config = getServletConfig(); 21 // 1.根据指定参数名获取参数值 22 String username = config.getInitParameter("username"); 23 String password = config.getInitParameter("password"); 24 System.out.println(username + " " + password); 25 // 2.获取所有初始化参数名 26 Enumeration<String> names = config.getInitParameterNames(); 27 while (names.hasMoreElements()) { 28 String name = names.nextElement(); 29 // 根据已获得的参数名获取参数值 30 String value = config.getInitParameter(name); 31 System.out.println(name + "---" + value); 32 } 33 // 3.获取Servlet名称 34 String servletName = config.getServletName(); 35 System.out.println(servletName); 36 37 // 4.获取contextpath 38 String contextPath = config.getServletContext().getContextPath(); 39 System.out.println(contextPath); 40 } 41 42 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 43 doGet(request, response); 44 } 45 46 }
web.xml相关配置如下:
1 <servlet> 2 <description></description> 3 <display-name>ServletDemo13</display-name> 4 <servlet-name>ServletDemo13</servlet-name> 5 <servlet-class>com.itheima.action.ServletDemo13</servlet-class> 6 <init-param> 7 <param-name>username</param-name> 8 <param-value>root</param-value> 9 </init-param> 10 <init-param> 11 <param-name>password</param-name> 12 <param-value>abc</param-value> 13 </init-param> 14 </servlet> 15 <servlet-mapping> 16 <servlet-name>ServletDemo13</servlet-name> 17 <url-pattern>/ServletDemo13</url-pattern> 18 </servlet-mapping>