写一个servlet项目

好的，下面是一个简单的servlet项目示例：

1. 首先创建一个名为`HelloWorldServlet`的Java类，继承自`javax.servlet.http.HttpServlet`。

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class HelloWorldServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.getWriter().write("Hello World!");
    }
}

2. 在`web.xml`中配置servlet：

<?xml version="1.0" encoding="UTF-8"?>
<web-app 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_3_0.xsd" version="3.0">
  <display-name>HelloWorldServlet</display-name>
  
  <servlet>
    <servlet-name>HelloWorldServlet</servlet-name>
    <servlet-class>HelloWorldServlet</servlet-class>
  </servlet>
  
  <servlet-mapping>
    <servlet-name>HelloWorldServlet</servlet-name>
    <url-pattern>/hello</url-pattern>
  </servlet-mapping>
  
</web-app>

3. 构建并运行项目，访问`http://localhost:8080/HelloWorldServlet/hello`即可看到`Hello World!`的输出。