Spring中的java自定义电子邮件服务需要帮助改进

Question

我有下面的代码可以很好地工作多达150个连续线程。任何超出此范围的操作都会导致服务器无响应。请帮助我就如何正确集成多线程提出建议。我在考虑ThreadPoolExecutor和ArrayBlockingQueue，但我想问一下是否已经有我可以使用的库或其他更适合此类的解决方案：

@Transactional
public class EmailServiceImpl implements EmailService{

private static final Logger log = Logger
        .getLogger(MailNotificationServiceImpl.class);
private JavaMailSender mailSender;
private MessageSource messageSource;
private FreeMarkerConfigurer freemarkerConfig;

public void sendEmail(final String subject, final String recipient, final ModelMap mm, final String emailTemplate, final String from) {

   try {
        MimeMessagePreparator preparator = new MimeMessagePreparator() {
            public void prepare(MimeMessage mimeMessage) throws Exception {
                MimeMessageHelper message = new MimeMeaassageHelper(

                mimeMessage);
                message.setFrom(from);
                message.setTo(recipient);
                message.setSubject(subject);

                //freemarker integration
                Template textTemplate = freemarkerConfig.getConfiguration().getTemplate(emailTemplate); // "/WEB-INF/email/*.ftl"
                log.debug(emailTemplate);
                final StringWriter textWriter = new StringWriter();
                textTemplate.process(mm, textWriter);

                message.setText(textWriter.toString(), true);
            }
        };
       Thread thread = new SendMail(preparator);
       thread.start();

    } catch (Exception e) {
        log.error(e);
    }          
}


class SendMail extends Thread {
    MimeMessagePreparator preparator;

    SendMail(MimeMessagePreparator preparator) {
        this.preparator = preparator;
    }

    public void run() {
        log.debug("About to send email:");
        mailSender.send(preparator);
        log.debug("Email send.");
    }
}



public void sendEmail(final String subject, final String recipient, final ModelMap mm, final String emailTemplate, final boolean flag, final String from) {
    if(flag){
        sendEmail(subject, recipient, mm, emailTemplate, from);
    }
}

public void sendEmail(final String subject, final String recipient, final ModelMap mm, final String emailTemplate, final boolean flag) {
    if(flag){
        sendEmail(subject, recipient, mm, emailTemplate, "support@domain.com");
    }
}    

public void sendEmail(final String subject, final String recipient, final ModelMap mm, final String emailTemplate) {
        sendEmail(subject, recipient, mm, emailTemplate, "support@domain.com");
}    

public void setMailSender(JavaMailSender mailSender) {
    this.mailSender = mailSender;
}

private String gm(String messageName) {
    return messageSource.getMessage(messageName, null, null);
}

public void setMessageSource(MessageSource messageSource) {
    this.messageSource = messageSource;
}

public void setFreemarkerConfig(FreeMarkerConfigurer freemarkerConfig) {
    this.freemarkerConfig = freemarkerConfig;
}

}

Answer 1

你应该慎重考虑使用ExcService服务。在所有处理器达到峰值，操作系统花费更多时间切换线程上下文之前，使用更多线程只能实现如此多的并发性

如果将任何给定时间运行的线程数限制为50个，那么总体吞吐量应该会很好

你可以这样尝试：

ExecutorService executor = Executors.newFixedThreadPool(50);

public void sendEmail(final String subject, final String recipient, final ModelMap mm, final String emailTemplate, final String from) {
 MimeMessagePreparator preparator = new MimeMessagePreparator() {
       // rest of your mail building logic
      };

  executor.submit(preparator);

}