Question

我目前正在编写一个非常简单的脚本，我收到的错误在提供的示例中没有弹出。我有一组代码和一个客户端来测试它。我尝试运行代码时收到此错误。我得到了三个实例，我尝试在客户端使用“新类”。

ClassClient.java:5: error: constructor Class in class Class cannot be applied to given types;

     Class code = new Class("1234");
                  ^
required: String,String,String
found: String
reason: actual and formal argument lists differ in length

这是第一组代码：

public class Class
{
//attributes
public  String code;
private String name;
private String credit;

//constructor
public Class(String newCode, String newName, String newCredit)
{
  setCode(newCode);
  setName(newName);
  setCredit(newCredit);
}

//get|sets

public String getCode()
{
   return code;
}

public void setCode(String newCode)
{
   code = newCode;
}

public String getName()
{
   return name;
}

 public void setName(String newName)
{
   name = newName;
}

public String getCredit()
{
   return credit;
}

public void setCredit(String newCredit)
{
   credit = newCredit;
}

public String toString()
{
return ("The code for this class is: "+code + "\n" + "The name for this class is :"+name + "\n" +  "The number of credits this course has is :"+credit);
}

public boolean equals(Object o)
{
if(!(o instanceof Class))
   return false;
else
{
   Class x = (Class) o;
   Class y = (Class) o;
   Class z = (Class) o;

   return(code.equals(x.code) || name.equals(y.name) || credit.equals(z.credit));
}


}//endelse
}//end class

以下是测试代码的客户端：

public class ClassClient
{
public static void main(String [] args)
  {
     Class code = new Class("1234");
     Class name = new Class("Java");
     Class credit = new Class("4");
     System.out.println("The code for this class is: "+code + "\n" + "The name for this class is :"+name + "\n" +  "The number of credits this course has is :"+credit);
  }
}

Answer 1

Constructor中{p> class接受3 String个参数而不是1。

您可以更改

 Class code = new Class("1234"); // you are calling single argument
 Class name = new Class("Java"); // but there is no matching 
 Class credit = new Class("4"); // constructor for this

要

 Class cl = new Class("1234","Java","4");

除了获取值，您还应该使用getter。

您可以更改

System.out.println("The code for this class is: "+code + "\n" 
      + "The name for this class is :"+name + "\n" 
             +  "The number of credits this course has is :"+credit);

要

System.out.println("The code for this class is: "+cl.getCode() + "\n" 
      + "The name for this class is :"+cl.getName() + "\n" 
             +  "The number of credits this course has is "+cl.getCredit());

Answer 2

如果你的Class类中有一个构造函数，你的ClassClient是正确的。

  //constructor

 public Class(String somethig)
   {
     // set somethig
  }

但在你的构造函数中它期望三个参数。但你只提供了一个。

简单Java问题实际和正式参数列表的长度不同

2 个答案: