<?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>bvgfeikbnhlnhfb</servlet-name>
<servlet-class>com.yanyu.Demo</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>bvgfeikbnhlnhfb</servlet-name>
<url-pattern>/test/demo</url-pattern>
</servlet-mapping>
</web-app>
去 添加 servlet 的依赖关系
添加 后xml 有报错，等 Demo 继承 HttpServlet 后 ，报错就会自动消失
package com.yanyu;
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.PrintWriter;
public class Demo extends HttpServlet {
// 重写 ctrl o]
/*
1. 重写 父类方法 doGet doPost
2. 没有 main() 也不需要写 ，tomcat 服务器 自己会写
3. 获取对象（ new 调用方法来返回一个对象） 调用方法
4. 操作
CTRL O 重写 父类 doGet 方法,改写 请求对象 和响应
删掉 super...
设置 响应到 浏览器的 编码 格式 和 类型 text / html
* 获取 响应到浏览器的 对象
*
*
* */
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// 设置 响应到 浏览器的 编码 格式 和 类型 text / html
response.setCharacterEncoding("utf-8");
response.setContentType("text/html");
// 获取 响应到浏览器的 对象
PrintWriter out = response.getWriter();
// out 就是响应到浏览器的 对象
out.println("hello world");
System.out.println("hello tomcat");
// 观察 "hello world") hello tomcat" 打印在哪里
}
}
- 设置 欢迎页面
<?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>aa</servlet-name>
<servlet-class>com.yanyu.Demo</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>aa</servlet-name>
<url-pattern>/test/demo</url-pattern>
</servlet-mapping>
<!-- 设置 首页 -->
<welcome-file-list>
<welcome-file>demo.jsp</welcome-file>
</welcome-file-list>
</web-app>
web04 往前端响应 代码
<?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>aa</servlet-name>
<servlet-class>com.yanyu.Login</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>aa</servlet-name>
<url-pattern>/test/login</url-pattern>
</servlet-mapping>
</web-app>
<%--
Created by IntelliJ IDEA.
User: Administrator
Date: 2024/6/3
Time: 15:57
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>$Title$</title>
</head>
<body>
<h1>欢迎使用</h1>
<a href="/test/login">启动服务</a>
</body>
</html>
package com.yanyu;
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.PrintWriter;
public class Login extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html");
response.setCharacterEncoding("utf-8");
PrintWriter out = response.getWriter();
out.print("<!DOCTYPE html>");
out.print("<html lang='en'>");
out.print("<head>");
out.print(" <meta charset='UTF-8'>");
out.print(" <meta http-equiv='X-UA-Compatible' content='IE=edge'>");
out.print(" <meta name='viewport' content='width=device-width, initial-scale=1.0'>");
out.print(" <title>Document</title>");
out.print("</head>");
out.print("<body>");
out.print(" <h1>欢迎登录</h1>");
out.print(" <form action='/test/info'>");
out.print(" 账号：<input type='text' name='username' >");
out.print(" 密码：<input type='text' name='password' >");
out.print(" <input type='submit' name='' value='登录'>");
out.print(" </form>");
out.print("");
out.print("</body>");
out.print("</html>");
}
}