在前面的博客里面,使用Servlet取得了request,response,config对象,实际上通过Servlet程序也可以取得session,application等内置对象。
1,通过HttpServletRequest取得HttpSession
<span style="white-space:pre"> </span>//返回当前的session public abstract HttpSession getSession(); //返回当前的session,如果没有则创建一个新的session对象返回 public abstract HttpSession getSession(boolean paramBoolean);
package linkin; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; public class LinkinServlet extends HttpServlet { private static final long serialVersionUID = 1L; @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { HttpSession session = req.getSession(); System.out.println(session.getId());//4214F4CE399E02730C3219CF0BD83623 session.setAttribute("age", 25); System.out.println(session.getAttribute("age"));//25 } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { this.doGet(req, resp); } }
<?xml version="1.0" encoding="UTF-8"?> <web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> <servlet> <servlet-name>LinkinServlet</servlet-name> <servlet-class>linkin.LinkinServlet</servlet-class> <init-param> <param-name>name</param-name> <param-value>LinkinPark...</param-value> </init-param> </servlet> <servlet-mapping> <servlet-name>LinkinServlet</servlet-name> <url-pattern>/LinkinServlet</url-pattern> </servlet-mapping> </web-app>
2,利用GenericServlet取得ServletContext实例
public ServletContext getServletContext() { return getServletConfig().getServletContext(); }
package linkin; import java.io.IOException; import javax.servlet.ServletContext; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class LinkinServlet extends HttpServlet { private static final long serialVersionUID = 1L; @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { ServletContext context = getServletContext(); //获取“/”,也就是项目实际在服务器上物理位置 System.out.println(context.getRealPath("/"));//E:\Workserver\apache-tomcat-6.0.37\webapps\linkin } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { this.doGet(req, resp); } }
<?xml version="1.0" encoding="UTF-8"?> <web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> <servlet> <servlet-name>LinkinServlet</servlet-name> <servlet-class>linkin.LinkinServlet</servlet-class> <init-param> <param-name>name</param-name> <param-value>LinkinPark...</param-value> </init-param> </servlet> <servlet-mapping> <servlet-name>LinkinServlet</servlet-name> <url-pattern>/LinkinServlet</url-pattern> </servlet-mapping> </web-app>
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时间: 2024-10-06 15:13:50