I want to lead an easy life.

<!-- https://mvnrepository.com/artifact/org.jxls/jxls-poi -->
<dependency>
    <groupId>org.jxls</groupId>
    <artifactId>jxls-poi</artifactId>
    <version>3.0.0</version>
</dependency>

import org.jxls.area.Area;
import org.jxls.builder.AreaBuilder;
import org.jxls.builder.xls.XlsCommentAreaBuilder;
import org.jxls.common.CellRef;
import org.jxls.common.Context;
import org.jxls.util.TransformerFactory;

// 出力部分抜粋
try (InputStream is = getTemplateSource(getUrl(), request);
        OutputStream os = response.getOutputStream()) {
    var transformer = TransformerFactory.createTransformer(is, os);
    AreaBuilder areaBuilder = new XlsCommentAreaBuilder(transformer);
    List<Area> xlsAreaList = areaBuilder.build();
    var xlsArea = xlsAreaList.get(0);
    var context = new Context();

    model.entrySet().forEach(mode -> context.putVar(mode.getKey(), mode.getValue()));

    xlsArea.applyAt(new CellRef("Sheet1!A1"), context);
    transformer.write();
}

import org.jxls.builder.JxlsStreaming;
import org.jxls.transform.poi.JxlsPoiTemplateFillerBuilder;

// 出力部分抜粋
try (InputStream is = getTemplateSource(getUrl(), request);
        OutputStream os = response.getOutputStream()) {
    JxlsPoiTemplateFillerBuilder.newInstance()
        .withStreaming(JxlsStreaming.STREAMING_ON)
        .withTemplate(is)
        .buildAndFill(model, new JxlsOutputStream(os));
}

import java.io.IOException;
import java.io.OutputStream;

import org.jxls.builder.JxlsOutput;

/**
 * Excelを書き込むためのOutputStreamを提供するクラス.
 */
public class JxlsOutputStream implements JxlsOutput {

    private OutputStream os;

    public JxlsOutputStream(OutputStream os) {
        this.os = os;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public OutputStream getOutputStream() throws IOException {
        return os;
    }
}

switch (code) {
case 401, 403:
    model.addAttribute("errorTitle", "403");
    break;
case 404:
    model.addAttribute("errorTitle", "404");
    break;
default:
    model.addAttribute("errorTitle", "error");
}

switch (code) {
case 401, 403 -> model.addAttribute("errorTitle", "403");
case 404 -> model.addAttribute("errorTitle", "404");
default -> model.addAttribute("errorTitle", "error");
};

int multiple = 0;

switch (unitSign) {
case M_BYTE:
    multiple = 1024 * 1024;
    break;
case K_BYTE:
    multiple = 1024;
    break;
case BYTE:
    multiple = 1;
}

int multiple = switch (unitSign) {
case M_BYTE -> 1024 * 1024;
case K_BYTE -> 1024;
case BYTE -> 1;
};

public static FileConverter createConverter(FileType fileType) {
    if (fileType == null) {
        throw new FileException("errors.fileType");
    }

    switch (fileType) {
    case XML:
        return createXmlConverter();
    case EXCEL:
        return createExcelConverter();
    case CSV:
        return createCsvConverter();
    default:
        throw new FileException("errors.fileType");
    }
}

public static FileConverter createConverter(FileType fileType) {
    return switch (fileType) {
    case XML -> createXmlConverter();
    case EXCEL -> createExcelConverter();
    case CSV -> createCsvConverter();
    case null, default -> throw new FileException("errors.fileType");
    };
}

plugins {
	id 'java'
}

group = 'oauth2hotmail'
version = '0.0.1-SNAPSHOT'

java {
	sourceCompatibility = '17'
}

configurations {
	compileOnly {
		extendsFrom annotationProcessor
	}
}

repositories {
	mavenCentral()
}

dependencies {
    implementation 'com.microsoft.azure:msal4j:1.14.2'
    implementation 'com.sun.mail:jakarta.mail:2.0.1'
}

tasks.named('test') {
	useJUnitPlatform()
}

public class HotmailOAuth {

    private static final String SCOPE = "https://graph.microsoft.com/.default";
    // アプリケーション(クライアント) ID
    private static final String CLIENT_ID = "";
    // クライアント シークレット
    private static final String CLIENT_SECRET = "";
    // OAuth 2.0 トークン エンドポイント (v2)
    private static final String AUTHORITY = "https://login.microsoftonline.com/ディレクトリ(テナント) ID/oauth2/v2.0/token";
    private static final String MAIL_FROM = "sender@foo.bar";
    private static final String MAIL_TO = "receiver@foo.bar";

    public static void main(String[] args) throws MalformedURLException, AddressException, MessagingException {
        // アクセス トークンを取得
        var token = getAccessTokenFromSecret();

        // SMTP セッションを作成
        var props = new Properties();
        props.put("mail.smtp.host", "それぞれのSMTPホスト名");
        props.put("mail.smtp.port", "587");
        props.put("mail.smtp.auth", "true");
        props.put("mail.smtp.auth.mechanisms", "XOAUTH2");
        props.put("mail.smtp.starttls.enable", "true");
        var session = Session.getDefaultInstance(props);

        // メールを作成
        var message = new MimeMessage(session);
        message.setFrom(new InternetAddress(MAIL_FROM));
        message.setRecipient(Message.RecipientType.TO, new InternetAddress(MAIL_TO));
        message.setSubject("OAuth 2.0認証を使って送信したメール");
        message.setText("このメールは、OAuth 2.0 認証を使って送信しました。");

        // メールを送信
        var transport = session.getTransport("smtp");
        transport.connect(MAIL_FROM, token);
        transport.sendMessage(message, message.getAllRecipients());
        transport.close();

        System.out.println("メールを送信しました。");
    }

    public static String getAccessTokenFromSecret() throws MalformedURLException {
      var credential = ClientCredentialFactory.createFromSecret(CLIENT_SECRET);

      var cca = ConfidentialClientApplication
              .builder(CLIENT_ID, credential)
              .authority(AUTHORITY)
              .build();

      var parameters = ClientCredentialParameters
              .builder(Set.of(SCOPE))
              .build();

      var result = cca.acquireToken(parameters).join();

      return result.accessToken();
    }
}