有哪些避免/处理长方法签名的方法？

Question

感觉这个方法签名太长了。有没有更明智或更优雅的方式来重写这个？  private Email createMail(long actualFileSize, String from, String recipient, String title,      String emailContent, MultipartFile attachment,      File file) {    Email mail = null;    if (actualFileSize <= Long.parseLong(emailFileSizeLimit)) {     mail = new Email(from, recipient, title,emailContent, null, file);    } else mail = new Email(from, recipient, title,emailContent, null, null);    return mail;  }

Answer 1

if (actualFileSize <= Long.parseLong(emailFileSizeLimit)) {

    file = null;

}

return new Email(from, recipient, title,emailContent, null, file);

1）重构。如果您认为参数过多，您可以将该方法分成更小的、可管理的方法。

if (actualFileSize <= Long.parseLong(emailFileSizeLimit)) {

    file = null;

}

createMail(from, recipient, title,emailContent, null, file);

******

private Email createMail(long actualFileSize, String from, String recipient, String 

    title, String emailContent, MultipartFile attachment, File file) {

   return new Email(from, recipient, title,emailContent, null, file);

}

2) DTO。您在 dto 中提供参数并将其作为请求/响应传递到整个链中，在需要时使用您需要的元素。当您需要创建时，您可以添加更多属性。您通过 setter 提供它们并在需要时传递

3) 建造者。您在类中完成了在完成操作后返回自身的逻辑。您可以通过对同一类调用不同的操作并返回结果来执行下一个操作。

Mail mail = mailBuilder.addName(name).add(stuff).compile(); // will call constructor inside

4) 工厂

让工厂包含所有方法并让它决定调用什么方法。它可以是静态的或托管的

factory.createBasicMail(name);

factory.createFileMail(name, file);

ps：为了您的心理健康，请使用 Lombok

Answer 2

这似乎很适合Builder 模式，在那里您需要以精心设计的方式构造一个新对象：

public class EmailBuilder {

  private Email mail;

  private String from;

  private String recipient;

  // other properties

  public EmailBuilder withFrom(String from) {

    this.from = from;

    return this;

  }

  public EmailBuilder withRecipient(String recipient) {

    this.recipient = recipient;

    return this;

  }

  public Email send() {

    mail = new Email(from, recipient, title,emailContent, null, file);

    return mail;

  }

}

用法

Email mail = new EmailBuilder()

   .withFrom("John Doe")

   .withRecipient("Mary Doe")

   .with...

   .send();