Backend/Servlet

Servlet

AIHYEONJI 2025. 6. 9. 12:45

Grandle 의 기본 언어는 Groovy

 

https://livekit.io/

 

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package com.koreait.servlet;

import java.io.*;

import jakarta.servlet.http.*;
import jakarta.servlet.annotation.*;

@WebServlet(name = "helloServlet", value = "/hello-servlet")
public class HelloServlet extends HttpServlet {
    private String message;
    
    // 서블릿이 최초 로딩될 때, 단 1회만 실행되는 초기화 메서드
    // 이곳에는 db연동, 서버 등을 일회성메서드를 주로 넣음
    public void init() {
        message = "Hello World!";
    }
    
    // url 호출 --> client의 GET 요청을 처리하는 구간
    // HttpServletRequest: 클라이언트 요청 정보를 담은 객체
    // HttpServletResponse : 서버에서 클라이언트로 전달될 응답 정보를 담은 객체
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
        // response.setContentType("text/html");
        // 한글 깨짐 방지 --> html의 charset=UTF-8
        response.setContentType("text/html; charset=UTF-8");
        // 실제 클래스 안에서 쓰이는 한글 깨짐 방지
        response.setCharacterEncoding("UTF-8");

        // Hello
        PrintWriter out = response.getWriter();
        out.println("<html><body>");
        out.println("<h1>" + message + "</h1>");
        out.println("</body></html>");
    }
    
    // 서블릿이 폼캣 종료 또는 언로드시 호출
    // 리소스 해제, 커넥션 풀 반환
    public void destroy() {
    }
}

 

 

*webapp 파일에서 controller 패키지 생성

파일구조

 

** main / java / com.koreait.servlet / controller / MyController

package com.koreait.servlet.controller;

import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

import java.io.IOException;

// value --> "*.korea" : 이름에 관계 없이 .korea로 끝난는 모든 URL 매핑
// http://localhost:8080/servlet/controller/join.korea  (get, post)
@WebServlet("*.korea")
public class MyController extends HttpServlet {
    private static final long serialVersionUID = 1L;
    public MyController() {}

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

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

    // get post 어느걸로 불리던 여기로 이동
    protected void doAction(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("UTF-8");
        String uri =  req.getRequestURI();
        String contextPath = req.getContextPath();
        String command = uri.substring(contextPath.length());

        // 전체주소
        System.out.println(uri);
        // root 파일을 알려줌
        System.out.println(contextPath);
        // 실제 내 리소스를 알려줌  --> routing해주면 됨
        System.out.println(command);

        if(command.equals("/controller/join.korea")){
            System.out.println("✅ 회원가입 작업");
        }else if(command.equals("/controller/login.korea")){
            System.out.println("✅ 로그인 작업");
        }else if(command.equals("/controller/info.korea")){
            System.out.println("✅ 회원정보 작업");
        }else if(command.equals("/controller/modify.korea")){
            System.out.println("✅ 회원정보 수정작업");
        }

    }
}

 

* .ajax

http://localhost:8080/servlet/controller/*.ajax

ex) get / post 동일하게 진행

  • regist.ajax
    • userid, password ,age , gender 전달
    • {"userid" : "전달한 값", "msg" : "가입되었습니다."}
    • userid, password 전달
    • {"userid" : "전달한 값", "msg" : "로그인되었습니다."}
    • response.setContentType("application/json; charset=UTF8;");
    • response.getWriter().write("{\"key\":\"Value\}");login.ajax 
package com.koreait.servlet.controller;

/*
import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

import java.io.IOException;
import java.io.PrintWriter;

@WebServlet("*.ajax")
public class AjaxController extends HttpServlet {
    private static final long serialVersionUID = 1L;
    public AjaxController() {}

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

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

    // get post 어느걸로 불리던 여기로 이동
    protected void doAction(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("UTF-8");
        resp.setContentType("application/json; charset=UTF8;");

        String uri = req.getRequestURI();
        String contextPath = req.getContextPath();
        String command = uri.substring(contextPath.length());
        String action = command.substring(command.lastIndexOf('/') + 1);

        // 전체주소
        System.out.println(uri);
        // root 파일을 알려줌
        System.out.println(contextPath);
        // 실제 내 리소스를 알려줌  --> routing 해주면 됨
        System.out.println(command);
        System.out.println(action);

        PrintWriter out = resp.getWriter();
        String userid = req.getParameter("userid");

        switch (action) {
            case "regist.ajax":
                String password = req.getParameter("password");
                String age = req.getParameter("age");
                String gender = req.getParameter("gender");

                out.write(String.format(
                        "{\"userid\":\"%s\",\"msg\":\"가입되었습니다.\"}",
                        userid
                ));
                break;
            case "login.ajax":
                String userpw = req.getParameter("password");
                out.write(String.format(
                        "{\"userid\":\"%s\",\"msg\":\"로그인되었습니다.\"}",
                        userid
                ));
                break;
        }
        out.flush();
    }
}
*/
import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

import java.io.IOException;

@WebServlet("*.ajax")
public class AjaxController extends HttpServlet {
    private static final long serialVersionUID = 1L;
    public AjaxController() {}

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

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

    protected void doAction(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("UTF-8");
        String uri = req.getRequestURI();
        String contextPath = req.getContextPath();
        String command = uri.substring(contextPath.length());

        System.out.println(req.getParameter("userid"));
        System.out.println(req.getParameter("password"));

        String userid = req.getParameter("userid");
        String password = req.getParameter("password");
        String age = req.getParameter("age");
        String gender = req.getParameter("gender");

        if(command.equals("/controller/regist.ajax")) {
            resp.setContentType("application/json; charset=UTF8;");
            resp.getWriter().write("{\"userid\":\"" + userid +"\", \"msg\":\"가입되었습니다.\"}");
        }else if(command.equals("/controller/login.ajax")) {
            resp.setContentType("application/json; charset=UTF8;");
            resp.getWriter().write("{\"userid\":\"" + userid +"\", \"msg\":\"로그인되었습니다.\"}");
        }
    }
}

 

<%--
    ajax.jsp
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>ajax</title>
    <script>
        function ajaxRegist(){
            const userid = document.querySelector("input[name='userid']").value
            const password = document.querySelector("input[name='password']").value
            const age = document.querySelector("input[name='age']").value
            const gender = document.querySelector("input[name='gender']:checked")?.value

            fetch("regist.ajax", {
                method: "POST",
                headers: {
                    'Content-Type':'application/x-www-form-urlencoded'
                },
                body: "userid=" + userid + "&password=" + password + "&age=" + age + "&gender=" + gender
            }).then(function(response){
                return response.json()
            }).then(function(data){
                console.log((data))
            }).catch(function(err){
                console.log(err);
            })

        }
        function ajaxLogin(){
            const userid = document.querySelector("input[name='userid']").value
            const password = document.querySelector("input[name='password']").value

            fetch("login.ajax", {
                method: "POST",
                headers: {
                    'Content-Type':'application/x-www-form-urlencoded'
                },
                body: "userid=" + userid + "&password=" + password
            }).then(function(response){
                return response.json()
            }).then(function(data){
                console.log((data))
            }).catch(function(err){
                console.log(err);
            })

        }
    </script>
</head>
<body>
<p>아이디: <input type="text" name="userid"></p>
<p>비밀번호: <input type="password" name="password"></p>
<p>나이: <input type="text" name="age"></p>
<p>성별: 남:<input type="radio" name="gender" value="남자"> 여:<input type="radio" name="gender" value="여자"></p>
<p><button type="button" onclick="ajaxRegist()">AJAX 회원가입</button></p>
<p><button type="button" onclick="ajaxLogin()">AJAX 로그인</button></p>
</body>
</html>

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