概述
1,servletConfig是servlet的配置对象,作用是获取servlet的初始化参数
2,子类:genericServlet 、HttpServlet
常用方法
获取ServletConfig对象:getServletConfig()
获取servlet初始化参数值:getInitParameter(String name)
获取servletContext对象:getServletContext()
获取servlet名称:getServletName(),即的值
配置web.xml
<servlet>
<servlet-name>ServletConfig</servlet-name>
<servlet-class>com.demo06_servlet_config.test</servlet-class>
<!-- 初始化参数 -->
<init-param>
<param-name>encoding</param-name>
<param-value>utf-8</param-value>
</init-param>
<!-- 可以配置多个初始化参数 -->
<init-param>
<param-name>ID</param-name>
<param-value>001</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>ServletConfig</servlet-name>
<url-pattern>/servlet_config</url-pattern>
</servlet-mapping>
配置servlet文件
package com.demo06_servlet_config;
import java.io.IOException;
import java.util.Enumeration;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
//@WebServlet("/servlet_config")
public class test extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//获取servlet对象
ServletConfig sc = this.getServletConfig();
//获取servlet名称。就是配置文件中的servlet-name
String name = sc.getServletName();
//获取初始化参数
String value = sc.getInitParameter("ID");
response.getWriter().println("========获取servlet名称测试====");
response.getWriter().println(name);
response.getWriter().println("======获取指定初始化参数的值测试====");
response.getWriter().println(value);
response.getWriter().println("========获取所有初始化名称测试====");
//获取初始化参数名称,因为返回值是String泛型,所以泛型接收
Enumeration<String> er = sc.getInitParameterNames();
while(er.hasMoreElements()) {
String name02 = er.nextElement();
String value02 = sc.getInitParameter(name02);
response.getWriter().println(name02);
response.getWriter().println(value02);
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}