3. 新建 Module,相当于 project,  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  选择 JARs or directories..., 
 
 
 
 
 
 
 
 
 
 
 
 
  需要执行 Put into Output Root; 
 
 
 
 
 
 
  可供所有 project 内 module 使用; 
 
 
 
 
 
  选择 JARs or directories..., 
 
 
 
 需要执行 Put in 
 to Output Root, 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
 
  
    
    
  
   
     
     
   package demo.controller;
   
     
     
   
import javax.servlet.ServletException;
   
     
     
   import javax.servlet.http.HttpServlet;
   
     
     
   import javax.servlet.http.HttpServletRequest;
   
     
     
   import javax.servlet.http.HttpServletResponse;
   
     
     
   import java.io.IOException;
   
     
     
   
public class HelloServlet extends HttpServlet {
   
     
     
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
   
     
     
   
 }
   
     
     
   
 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
   
     
     
   
 }
   
     
     
   }
  
    
    
   
 
 
 
  
 
  
    
    
  
   
     
     
   public class HelloServlet extends HttpServlet {
   
     
     
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
   
     
     
    doGet(request,response);
   
     
     
    }
   
     
     
   
 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
   
     
     
    response.getWriter().println("Hello world!");
   
     
     
    }
   
     
     
   }
  
    
    
   
 
 
 
  
 
  
    
    
  
   
     
     
   <?xml version="1.0" encoding="UTF-8"?>
   
     
     
   <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
   
     
     
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   
     
     
    xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
   
     
     
    version="4.0">
   
     
     
    <servlet>
   
     
     
    <servlet-name>HelloServlet</servlet-name>
   
     
     
    <servlet-class>demo.controller.HelloServlet</servlet-class>
   
     
     
    </servlet>
   
     
     
   </web-app>
  
    
    
   
 
 
 
  
 <?xml version="1.0" encoding="UTF-8"?><web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" version="4.0"> <servlet> <servlet-name>HelloServlet</servlet-name> <servlet-class>demo.HelloServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>HelloServlet</servlet-name> <url-pattern>/hello</url-pattern> </servlet-mapping></web-app>