我如何只实例化每个构造函数变量和多个构造函数？[重复]

Question

我需要避免重复的代码与这些构造函数，所以我想知道是否有一种方法来实例化这些变量只有一个？我看到了很多关于链接的帖子，但我还没有让它正常工作。

class Trainingsschema
{
    // create an arrayList for every oefening
    private String klant;
    private String trainer;
    private Integer nummer;
    private ArrayList<Oefening> alleOefeningen;

    // two different constructors to correctly initialise the class variables
    public Trainingsschema(String klant, String trainer)
    {
        this.klant = klant;
        this.trainer = trainer;
        this.nummer = this.volgendUniekNummer();
        this.alleOefeningen = this.initialiseerOefeningen();
    }

    public Trainingsschema(String klant)
    {
        this.klant = klant;
        this.trainer = null;
        this.nummer = this.volgendUniekNummer();
        this.alleOefeningen = this.initialiseerOefeningen();
    }

Answer 1

应该有一个构造函数来初始化所有变量。使用其他构造函数的默认值调用它，如下所示：

class Trainingsschema
{
    // create an arrayList for every oefening
    private String klant;
    private String trainer;
    private Integer nummer;
    private ArrayList<Oefening> alleOefeningen;

    // two different constructors to correctly initialise the class variables
    public Trainingsschema(String klant, String trainer)
    {
        this.klant = klant;
        this.trainer = trainer;
        this.nummer = this.volgendUniekNummer();
        this.alleOefeningen = this.initialiseerOefeningen();
    }

    public Trainingsschema(String klant)
    {
        this(klant, null);
    }
}