标签：get tps 对象 element generated init ota blog override
在Servlet的配置文件中，可以使用一个或者多个<init-param>标签为servlet配置一些初始化参数。
当servlet配置了初始化常熟后，web容器在常见servlet实例对象时，会自动将这些初始化参数封装到servletconfig对象中，并在调用servlet的init方法时，将servletconfig对象传递给servlet，进而，程序员通过servletconfig对象就可以得到当前servlet的初始化参数信息。
阅读ServletConfig API，并举例说明该对象的作用：
获得字符集编码
获得数据库连接信息
获得配置文件，查看structs案例的web.xml文件
1 package cn.itcast.servlet; 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.annotation.WebServlet; 9 import javax.servlet.http.HttpServlet; 10 import javax.servlet.http.HttpServletRequest; 11 import javax.servlet.http.HttpServletResponse; 12 13 14 public class ConfigServletDemo1 extends HttpServlet { 15 private static final long serialVersionUID = 1L; 16 private ServletConfig config; 17 18 19 20 @Override 21 protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { 22 //获取指定的初始化参数 23 String value = config.getInitParameter("xxx"); 24 resp.getOutputStream().write(value.getBytes()); 25 26 //获取所有初始化参数 27 Enumeration e = config.getInitParameterNames(); 28 while(e.hasMoreElements()){ 29 String name = (String) e.nextElement(); 30 value = config.getInitParameter(name); 31 resp.getOutputStream().write((name + "=" + value + "<br />").getBytes()); 32 } 33 } 34 35 /** 36 * 这个方法有什么用？ 37 * 1.配置初始化参数，配置字符集 38 * <init-param> 39 <param-name>charset</param-name> 40 <param-value>utf-8</param-value> 41 </init-param> 42 * 2.配置数据库连接设置 43 * <init-param> 44 * <param-name>url</param-name> 45 * <param-value>jdbc:mysql://localhost:3306/test</param-value> 46 * </init-param> 47 * <init-param> 48 * <param-name>username</param-name> 49 * <param-value>root</param-value> 50 * </init-param> 51 * <init-param> 52 * <param-name>password</param-name> 53 * <param-value>root</param-value> 54 * </init-param> 55 * 3. 56 */ 57 58 59 60 61 @Override 62 public void init(ServletConfig config) throws ServletException { 63 this.config = config; 64 } 65 66 67 68 }
下面的方法更简洁，在以后的开发过程中使用下面的方法
1 package cn.itcast.servlet; 2 3 import java.io.IOException; 4 5 import javax.servlet.ServletConfig; 6 import javax.servlet.ServletException; 7 import javax.servlet.annotation.WebServlet; 8 import javax.servlet.http.HttpServlet; 9 import javax.servlet.http.HttpServletRequest; 10 import javax.servlet.http.HttpServletResponse; 11 12 /** 13 * Servlet implementation class ConfigServletDemo2 14 */ 15 16 public class ConfigServletDemo2 extends HttpServlet { 17 private static final long serialVersionUID = 1L; 18 19 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 20 ServletConfig config = this.getServletConfig(); 21 String value = config.getInitParameter("xxx"); 22 response.getOutputStream().write(value.getBytes()); 23 } 24 25 26 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 27 // TODO Auto-generated method stub 28 doGet(request, response); 29 } 30 31 }
标签：get tps 对象 element generated init ota blog override
原文地址：http://www.cnblogs.com/LoganChen/p/6375055.html
