如何在编程中使用liferay内置的电子邮件模板？

import com.liferay.mail.kernel.model.MailMessage;
import com.liferay.mail.kernel.service.MailServiceUtil;
import com.liferay.portal.kernel.template.TemplateConstants;
import com.liferay.portal.kernel.template.TemplateResource;
import com.liferay.portal.kernel.template.TemplateResourceLoaderUtil;
import com.liferay.portal.kernel.template.TemplateVariableGroup;
import com.liferay.portal.kernel.util.StringUtil;

// 获取电子邮件模板的ID或名称
long templateId = 12345;

// 设置收件人、主题、内容等信息
String recipient = "example@example.com";
String subject = "Hello from Liferay";
String body = "This is a test email.";

// 获取电子邮件模板内容
TemplateResource templateResource = TemplateResourceLoaderUtil.getTemplateResource(
    TemplateConstants.LANG_TYPE_FTL, templateId);
String templateContent = StringUtil.read(templateResource.getReader());

// 替换电子邮件模板中的变量
templateContent = StringUtil.replace(
    templateContent,
    new String[] {"$RECIPIENT", "$SUBJECT", "$BODY"},
    new String[] {recipient, subject, body});

// 创建电子邮件消息
MailMessage mailMessage = new MailMessage();
mailMessage.setTo(new InternetAddress(recipient));
mailMessage.setSubject(subject);
mailMessage.setBody(templateContent);
mailMessage.setHTMLFormat(true);

// 发送电子邮件
MailServiceUtil.sendEmail(mailMessage);