JAVA-EE解析ServletContext接口的作用和方法------计算机网络经典

系统管理员 2024-03-01 07:59 48阅读 0赞

> package com.bjpowernode.javaweb.servlet0;
> 
> import jakarta.servlet.*;
> 
> import java.io.IOException;
> import java.io.PrintWriter;
> import java.util.Enumeration;
> 
> public class ConfigServletTest extends GenericServlet
> {
> @Override
> public void service(ServletRequest servletRequest, ServletResponse servletResponse) throws ServletException, IOException
> {
> servletResponse.setContentType("text/html;charset=UTF-8");
> PrintWriter writer = servletResponse.getWriter();
> //ServletConfig是什么?
> //是Servlet规范中的一员
> //获取ServletConfig对象
> ServletConfig servletConfig = this.getServletConfig();
> writer.println("该对象是" + servletConfig);
> //换成jetty之类的web容器,包名和类名不一样了,但是还是实现了一样的方法
> writer.println(" ");
> writer.println(servletConfig.getServletName());
> writer.println(" ");
> writer.println(servletConfig.getServletContext());
> writer.println(" ");
> //<init-param>这个配置信息会被包装进ServletConfig内部
> //我们可以通过ServletConfig获取到这个初始化参数信息
> Enumeration<String> initParameterNames = servletConfig.getInitParameterNames();
> //是否有更多元素
> while (initParameterNames.hasMoreElements())
> {
> String name = initParameterNames.nextElement();
> String initParameter = servletConfig.getInitParameter(name);
> writer.println(name + ":" + initParameter);
> writer.println(" ");
> }
> ServletContext servletContext = servletConfig.getServletContext();
> ServletContext servletContext1 = getServletContext();
> writer.println(servletContext);
> writer.println(" ");
> writer.println(servletContext1);
> //getInitParameter(),getInitParameterNames(),getServletContext(),getServletName()
> //这四个方法也可以通过当前对象(继承了GenericServlet)直接调用
> }
> }
> 
> package com.bjpowernode.javaweb.servlet0;
> 
> import jakarta.servlet.*;
> 
> import java.io.IOException;
> import java.io.PrintWriter;
> import java.util.Enumeration;
> 
> public class ConfigServletTest extends GenericServlet
> {
> @Override
> public void service(ServletRequest servletRequest, ServletResponse servletResponse) throws ServletException, IOException
> {
> servletResponse.setContentType("text/html;charset=UTF-8");
> PrintWriter writer = servletResponse.getWriter();
> //ServletConfig是什么?
> //是Servlet规范中的一员
> //获取ServletConfig对象
> ServletConfig servletConfig = this.getServletConfig();
> writer.println("该对象是" + servletConfig);
> //换成jetty之类的web容器,包名和类名不一样了,但是还是实现了一样的方法
> writer.println(" ");
> writer.println(servletConfig.getServletName());
> writer.println(" ");
> writer.println(servletConfig.getServletContext());
> writer.println(" ");
> //<init-param>这个配置信息会被包装进ServletConfig内部
> //我们可以通过ServletConfig获取到这个初始化参数信息
> Enumeration<String> initParameterNames = servletConfig.getInitParameterNames();
> //是否有更多元素
> while (initParameterNames.hasMoreElements())
> {
> String name = initParameterNames.nextElement();
> String initParameter = servletConfig.getInitParameter(name);
> writer.println(name + ":" + initParameter);
> writer.println(" ");
> }
> ServletContext servletContext = servletConfig.getServletContext();
> ServletContext servletContext1 = getServletContext();
> writer.println(servletContext);
> writer.println(" ");
> writer.println(servletContext1);
> //getInitParameter(),getInitParameterNames(),getServletContext(),getServletName()
> //这四个方法也可以通过当前对象(继承了GenericServlet)直接调用
> }
> }

> <?xml version="1.0" encoding="UTF-8"?>
> <web-app xmlns="https://jakarta.ee/xml/ns/jakartaee"
> xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
> xsi:schemaLocation="https://jakarta.ee/xml/ns/jakartaee https://jakarta.ee/xml/ns/jakartaee/web-app_6_0.xsd"
> version="6.0">
> 
> <context-param>
> <param-name>pageSize</param-name>
> <param-value>10</param-value>
> </context-param>
> <context-param>
> <param-name>startIndex</param-name>
> <param-value>0</param-value>
> </context-param>
> <servlet>
> <servlet-name>AServlet</servlet-name>
> <servlet-class>com.powernode.javaweb.servlet.AServlet</servlet-class>
> </servlet>
> <servlet-mapping>
> <servlet-name>AServlet</servlet-name>
> <url-pattern>/AServlet</url-pattern>
> </servlet-mapping>
> <servlet>
> <servlet-name>BServlet</servlet-name>
> <servlet-class>com.powernode.javaweb.servlet.BServlet</servlet-class>
> </servlet>
> <servlet-mapping>
> <servlet-name>BServlet</servlet-name>
> <url-pattern>/BServlet</url-pattern>
> </servlet-mapping>
> </web-app>
> 
> <?xml version="1.0" encoding="UTF-8"?>
> <web-app xmlns="https://jakarta.ee/xml/ns/jakartaee"
> xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
> xsi:schemaLocation="https://jakarta.ee/xml/ns/jakartaee https://jakarta.ee/xml/ns/jakartaee/web-app_6_0.xsd"
> version="6.0">
> 
> <context-param>
> <param-name>pageSize</param-name>
> <param-value>10</param-value>
> </context-param>
> <context-param>
> <param-name>startIndex</param-name>
> <param-value>0</param-value>
> </context-param>
> <servlet>
> <servlet-name>AServlet</servlet-name>
> <servlet-class>com.powernode.javaweb.servlet.AServlet</servlet-class>
> </servlet>
> <servlet-mapping>
> <servlet-name>AServlet</servlet-name>
> <url-pattern>/AServlet</url-pattern>
> </servlet-mapping>
> <servlet>
> <servlet-name>BServlet</servlet-name>
> <servlet-class>com.powernode.javaweb.servlet.BServlet</servlet-class>
> </servlet>
> <servlet-mapping>
> <servlet-name>BServlet</servlet-name>
> <url-pattern>/BServlet</url-pattern>
> </servlet-mapping>
> </web-app>