创建类

表单页面代码

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>表单页面</title>
</head>
<body>
<form method="get" action="ServletDemo2">
    <input type="text" name="firstName" placeholder="请输入名 ">
    <input type="text" name="secondName" placeholder="请输入姓 ">
    <input type="submit" value="提交" >
</form>

</body>
</ht

Java代码

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

public class ServletDemo2 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //处理表单数据
        String firstName = req.getParameter("firstName");
        String secondName = req.getParameter("secondName");
        //构造一个响应页面
        resp.setContentType("text/html; charset=utf-8");
        //一旦调用getWriter方法，此时header的内容就不能更改
        Writer writer = resp.getWriter();
        writer.write("<html>");
        writer.write("firstName: "+firstName);
        writer.write("<br/>");
        writer.write("secondMame: "+secondName);
        writer.write("</html>");
    }
}

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_3_1.xsd"
         version="3.1"
         metadata-complete="true">

  <servlet>
    <servlet-name>ServletDemo2</servlet-name>
    <servlet-class>ServletDemo.ServletDemo2</servlet-class>
    //因为包名为Servlet，所以在类名前要加上包名，这样才能找到类
  </servlet>
  <servlet-mapping>
    <servlet-name>ServletDemo2</servlet-name>
    <url-pattern>/ServletDemo2</url-pattern>
  </servlet-mapping>
</web-app>