Question

我需要使用默认构造函数创建一个方法，该方法将name设置为空字符串，并将credits和contactHours都设置为零。怎么做？谢谢，彼得。

Answer 1

方法没有构造函数...类。例如：

public class Dummy
{
    private int credits;
    private int contactHours;
    private String name;

    public Dummy()
    {
        name = "";
        credits = 0;
        contactHours = 0;
    }

    // More stuff here, e.g. property accessors
}

您实际上没有设置来设置credits或contactHours，因为int类型默认为0，无论如何。

你可能想要至少一个带有初始值的构造函数 - 在这种情况下，你的无参数构造函数可以委托给它：

public class Dummy
{
    private String name;
    private int credits;
    private int contactHours;

    public Dummy()
    {
        this("", 0, 0);
    }

    public Dummy(String name, int credits, int contactHours)
    {
        this.name = name;
        this.credits = credits;
        this.contactHours = contactHours;
    }

    // More stuff here, e.g. property accessors
}

Answer 2

public class Test {
 private String name;
 private int credits;
 private int contactHours;

 public Test {

  this( "", 0, 0);

 }
public Test (String name, int credits, int contactHours) {
 this.name = name;
 this.credits = credits;
 this.contactHours = contactHours;
 }

// more code here
}

Answer 3

public class Bibabu{
  private String name;
  private int credits;
  private int contactHours;

  public Bibabu(){
    name = "";         // you could also write this.name and so on...
    credits = 0;
    contactHours= 0;
  }

  // more code here

}

Answer 4

您不需要构造函数：

public class Dummy
{
    private int credits = 0;
    private int contactHours=0;
    private String name="";
/*
    public Dummy()
    {
        name = "";
        credits = 0;
        contactHours = 0;
    }
*/  
    // More stuff here, e.g. property accessors
}

Answer 5

//constructor
     public Account(int id, double balance, Person owner){

        this.id = id;
        this.balance = balance;
        this.owner = owner;

在Java中创建默认构造函数

5 个答案: