如何编码日语字符javamail

import javax.mail.*;
import javax.mail.internet.*;
import java.util.Properties;

Properties props = new Properties();
props.put("mail.smtp.host", "SMTP服务器地址");
props.put("mail.smtp.auth", "true");
props.put("mail.smtp.port", "SMTP服务器端口号");
props.put("mail.smtp.starttls.enable", "true"); // 如果需要使用TLS加密，启用此选项

Session session = Session.getInstance(props, new Authenticator() {
    protected PasswordAuthentication getPasswordAuthentication() {
        return new PasswordAuthentication("你的邮箱地址", "你的邮箱密码");
    }
});

MimeMessage message = new MimeMessage(session);
message.setFrom(new InternetAddress("发件人邮箱地址"));
message.setRecipient(Message.RecipientType.TO, new InternetAddress("收件人邮箱地址"));
message.setSubject("邮件主题");
message.setText("邮件内容");

Transport.send(message);

MimeMessage message = new MimeMessage(session);
message.setHeader("Content-Type", "text/plain; charset=UTF-8");