【05 Servlet 注解开发& web简单交互】-优快云博客

本文链接：https://blog.youkuaiyun.com/qq_43520227/article/details/129850282

Servlet 注解开发笔记记录

一、注解开发
- 1.@WebServlet(value = "/")
- 2.手动创建Servlet容器
二、web交互
- 1.需求
- 2.实现

一、注解开发

1.@WebServlet(value = “/”)

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

/**
 * 基于注解开发
 */
@WebServlet("/")
public class ServletDemo1 extends HttpServlet {
    @Override
    public void init() throws ServletException {
        System.out.println("111");
    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println(":login is running");
    }

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

2.手动创建Servlet容器

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import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
/**
 * servlet基本功能类
 */
public class ServletDemo2 extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println(":ServletDemo02 is running");
    }

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



import javax.servlet.ServletContainerInitializer;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRegistration;
import java.util.Set;

/**
 * 注册配置servlet的功能类
 */

public class MyRegister implements ServletContainerInitializer {
    @Override
    public void onStartup(Set<Class<?>> set, ServletContext servletContext) throws ServletException {
        //完成servlet的创建和配置
        //1.创建ServletDeni02对象
        ServletDemo2 servletDemo2=new ServletDemo2();
        //2.在ServletContext对象中添加Servlet，并得到Servlet的动态配置对象
        ServletRegistration.Dynamic registration = servletContext.addServlet("servletDemo2", servletDemo2);
        //3.配置Servlet
        registration.addMapping("/servletDemo2");//映射访问资源的路径
        registration.setLoadOnStartup(1);//加载的时候创建
        
        
    }
}

在src下建立
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二、web交互

1.需求

通过页面请求将数据存到文件中
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2.实现

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>保存学生信息</title>
</head>
<body>
<form action="/stu" method="get" autocomplete="off">
    学生姓名：<input type="text" name="username"><br/>
    学生年龄：<input type="number" name="age"><br/>
    学生成绩：<input type="number" name="score"><br/>
    <button type="submit">保存</button>
</form>

</body>
</html>

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;

@WebServlet("/stu")
public class StudentServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //获取表单数据 存储到文件
        String username = req.getParameter("username");
        System.out.println("username:"+username);
        String age = req.getParameter("age");
        System.out.println("age:"+age);
        String score = req.getParameter("score");
        System.out.println("score:"+score);

        //采用字符输出流
        BufferedWriter bw=new BufferedWriter(new FileWriter("d:/stu.txt",true));
        bw.write(username+","+age+","+score);
        bw.close();

        //响应客户端
        PrintWriter pw = resp.getWriter();
        pw.println("Save Successful!");
        pw.close();
    }

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