JAVA-EE使用注解代替XML配置的方式实现将Servlet服务配置到Web容器内------计算机网络经典

待我称王封你为后i 2024-02-22 07:04 35阅读 0赞

>     package com.powernode.javaweb.servlet;
>     
>     import jakarta.servlet.ServletException;
>     import jakarta.servlet.annotation.WebServlet;
>     import jakarta.servlet.http.HttpServlet;
>     import jakarta.servlet.http.HttpServletRequest;
>     import jakarta.servlet.http.HttpServletResponse;
>     
>     import java.io.IOException;
>     import java.io.PrintWriter;
>     
>     //@WebServlet(urlPatterns = "/Welcome",name = "Welcome")
>     //也可以用value来指定Servlet的映射路径
>     //@WebServlet(value = "/Welcome")
>     //如果路径和name一致,直接写在注解内也能生效
>     @WebServlet("/Welcome")
>     public class WelcomeServlet extends HttpServlet
>     {
>         @Override
>         protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
>             response.setContentType("text/html;charset=UTF-8");
>             PrintWriter out = response.getWriter();
>             out.println("Servlet欢迎你");
>         }
>     }
> 
>     package com.powernode.javaweb.servlet;
>     
>     import jakarta.servlet.ServletException;
>     import jakarta.servlet.annotation.WebServlet;
>     import jakarta.servlet.http.HttpServlet;
>     import jakarta.servlet.http.HttpServletRequest;
>     import jakarta.servlet.http.HttpServletResponse;
>     
>     import java.io.IOException;
>     import java.io.PrintWriter;
>     
>     //@WebServlet(urlPatterns = "/Welcome",name = "Welcome")
>     //也可以用value来指定Servlet的映射路径
>     //@WebServlet(value = "/Welcome")
>     //如果路径和name一致,直接写在注解内也能生效
>     @WebServlet("/Welcome")
>     public class WelcomeServlet extends HttpServlet
>     {
>         @Override
>         protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
>             response.setContentType("text/html;charset=UTF-8");
>             PrintWriter out = response.getWriter();
>             out.println("Servlet欢迎你");
>         }
>     }

> package com.powernode.javaweb.servlet;
> 
> import jakarta.servlet.Servlet;
> import jakarta.servlet.ServletException;
> import jakarta.servlet.annotation.WebInitParam;
> import jakarta.servlet.annotation.WebServlet;
> import jakarta.servlet.http.HttpServlet;
> import jakarta.servlet.http.HttpServletRequest;
> import jakarta.servlet.http.HttpServletResponse;
> 
> import java.io.IOException;
> import java.io.PrintWriter;
> import java.util.Enumeration;
> 
> //loadOnStartup启动时创建对象<loadOnStartup = 1>
> @WebServlet(name = "Hello",urlPatterns = {"/Hello1","/Hello2"},loadOnStartup = 1,
> initParams = {@WebInitParam(name = "user",value = "root"),@WebInitParam(name = "password",value = "abc123"),
> @WebInitParam(name = "driver",value = "com.mysql.jdbc.Driver")})
> public class HelloServlet extends HttpServlet
> {
> public HelloServlet() {
> System.out.println("Hello启动!");
> }
> 
> @Override
> protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
> {
> //获取Servlet名字
> String servletName = getServletName();
> response.setContentType("text/html;charset=UTF-8");
> PrintWriter out = response.getWriter();
> out.println(servletName);
> out.println(" ");
> out.println(request.getServletPath());
> Enumeration<String> names = getInitParameterNames();
> out.println(" ");
> while(names.hasMoreElements())
> {
> String name = names.nextElement();
> String value = getInitParameter(name);
> out.println(name + ":" + value);
> out.println(" ");
> }
> }
> }
> 
> package com.powernode.javaweb.servlet;
> 
> import jakarta.servlet.Servlet;
> import jakarta.servlet.ServletException;
> import jakarta.servlet.annotation.WebInitParam;
> import jakarta.servlet.annotation.WebServlet;
> import jakarta.servlet.http.HttpServlet;
> import jakarta.servlet.http.HttpServletRequest;
> import jakarta.servlet.http.HttpServletResponse;
> 
> import java.io.IOException;
> import java.io.PrintWriter;
> import java.util.Enumeration;
> 
> //loadOnStartup启动时创建对象<loadOnStartup = 1>
> @WebServlet(name = "Hello",urlPatterns = {"/Hello1","/Hello2"},loadOnStartup = 1,
> initParams = {@WebInitParam(name = "user",value = "root"),@WebInitParam(name = "password",value = "abc123"),
> @WebInitParam(name = "driver",value = "com.mysql.jdbc.Driver")})
> public class HelloServlet extends HttpServlet
> {
> public HelloServlet() {
> System.out.println("Hello启动!");
> }
> 
> @Override
> protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
> {
> //获取Servlet名字
> String servletName = getServletName();
> response.setContentType("text/html;charset=UTF-8");
> PrintWriter out = response.getWriter();
> out.println(servletName);
> out.println(" ");
> out.println(request.getServletPath());
> Enumeration<String> names = getInitParameterNames();
> out.println(" ");
> while(names.hasMoreElements())
> {
> String name = names.nextElement();
> String value = getInitParameter(name);
> out.println(name + ":" + value);
> out.println(" ");
> }
> }
> }