无法编译servlet文件。

Question

我正在测试一个演示servlet文件但是，该servlet似乎没有回应。我无法理解这个问题。

当我点击提交的HTML表单的URL是 本地主机：8080 /啤酒-V1/SelectBeer.do

但是，它不应该是/ BeerSelect？由于@WebServlet（“/ BeerSelect”）???

的web.xml

<?xml version="1.0" encoding="UTF-8"?> 
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xmlns="http://java.sun.com/xml/ns/javaee" 
xmlns:web="http://java.sun.com/xml/ns/javaee/web- app_2_5.xsd" 
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee  
http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" metadata-complete="false" 
version="3.0"> 

<servlet> 
<servlet-name>CH3 Beer</servlet-name> 
<servlet-class>com.example.web.BeerSelect</servlet-class> 
</servlet> 
<servlet-mapping> 
<servlet-name>CH3 Beer</servlet-name> 
<url-pattern>/SelectBeer.do</url-pattern> 
</servlet-mapping> 
</web-app> 

BeerSelect.java

package com.example.web; 

import java.io.IOException; 
import java.io.PrintWriter; 

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("/BeerSelect") 
public class BeerSelect extends HttpServlet { 
private static final long serialVersionUID = 1L; 

public BeerSelect() { 
    super(); 
} 

@Override 
protected void doPost(HttpServletRequest request, 
     HttpServletResponse response) throws ServletException, IOException { 

    response.setContentType("text/html"); 
    PrintWriter out = response.getWriter(); 
    out.println("Beer Selection Advice<br>"); 

    String c = request.getParameter("color"); 
    out.println("<br> Got Beer Color " + c); 

} 

}

Answer 1

当我点击提交的HTML表单的URL为localhost：8080/Beer-V1/SelectBeer.do

但是，它不应该是/ BeerSelect？由于@WebServlet（“/ BeerSelect”）???

1. Web容器同伙“上下文路径”为每个部署的web应用，并在你的情况，我相信这是“啤酒-V1”。

2. 您已经覆盖web.xml中的映射如下，因此你看到*。做

   <servlet-mapping> 
       <servlet-name>CH3 Beer</servlet-name> 
       <url-pattern>/SelectBeer.do</url-pattern> 
   </servlet-mapping> 
   

的XML DD覆盖注解。