1.创建空项目

2.配置web项目

3.配置Tomcat

4.加载Tomcat包

5.创建HelloWorldServlet类

public class controller extends HttpServlet {
    @Override
    //get请求
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    	//页面显示servlet
        resp.getWriter().println("servlet");
    }

    @Override
    //post请求
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

    }
}

6.配置web.xml

<?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>
<!--        java类路径别名-->
        <servlet-name>hello</servlet-name>
<!--        引入java类-->
        <servlet-class>com.lx.controller</servlet-class>
    </servlet>
    <servlet-mapping>
<!--        使用别名-->
        <servlet-name>hello</servlet-name>
<!--        浏览器资源路径-->
        <url-pattern>/hello</url-pattern>
    </servlet-mapping>
</web-app>

7.运行

get与post请求

<!--  /servletWebDemo：是配置Tomcat中指定的地址-->
<!--  /login：是web.xml中的<url-pattern>/login</url-pattern>-->
  <form action="/servletWebDemo/login" method="get">
    <label>用户名：</label>
    <input type="text" name="userName">
    <br>
    <br>
    <label>密码:</label>
    <input type="password" name="passWord">
    <br>
    <br>
    <button type="submit">提交</button>
  </form>

public class controller extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		//设置请求中文字符
        req.setCharacterEncoding("utf-8");
        //设置响应中文字符
        resp.setContentType("text/html;charset=utf-8");
        String userName = req.getParameter("userName");
        String passWord = req.getParameter("passWord");
        resp.getWriter().println(userName);
        resp.getWriter().println();
        resp.getWriter().println(passWord);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req,resp);
    }
}