在Java中处理多个构造函数的最佳方式 [英] Best way to handle multiple constructors in Java

问题描述

我一直想知道在Java中处理多个构造函数的最好的（即最干净/最安全/最有效的）方法是什么？特别是当在一个或多个构造函数中不指定所有字段时：

I've been wondering what the best (i.e. cleanest/safest/most efficient) way of handling multiple constructors in Java is? Especially when in one or more constructors not all fields are specified:

public class Book
{

    private String title;
    private String isbn;

    public Book()
    {
      //nothing specified!
    }

    public Book(String title)
    {
      //only title!
    }

    ...     

}

$ b b

如果未指定字段，该怎么办？我到目前为止一直在类中使用默认值，以便字段永远不会为空，但是是一种好的做事方式。

What should I do when fields are not specified? I've so far been using default values in the class so that a field is never null, but is that a "good" way of doing things?

推荐答案

略微简化的答案：

public class Book
{
    private final String title;

    public Book(String title)
    {
      this.title = title;
    }

    public Book()
    {
      this("Default Title");
    }

    ...
}

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