如何在java中从.eml文件中获取内部主题

<dependency>
    <groupId>javax.mail</groupId>
    <artifactId>javax.mail-api</artifactId>
    <version>1.6.2</version>
</dependency>
<dependency>
    <groupId>com.sun.mail</groupId>
    <artifactId>javax.mail</artifactId>
    <version>1.6.2</version>
</dependency>

import javax.mail.*;
import javax.mail.internet.MimeMessage;
import java.io.FileInputStream;
import java.util.Properties;

public class EmlParser {
    public static void main(String[] args) {
        try {
            // 读取.eml文件
            FileInputStream emlFile = new FileInputStream("path/to/email.eml");

            // 创建Properties对象，用于配置JavaMail会话
            Properties properties = new Properties();
            properties.put("mail.mime.charset", "UTF-8");

            // 创建会话
            Session session = Session.getDefaultInstance(properties);

            // 创建MimeMessage对象
            MimeMessage message = new MimeMessage(session, emlFile);

            // 获取内部主题
            String subject = message.getSubject();

            // 打印内部主题
            System.out.println("内部主题: " + subject);

            // 关闭文件流
            emlFile.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}