Java找不到构造函数

Question

像大多数新程序员一样,我有一个小但重要的问题,我无法弄清楚.我的程序不会拉我的构造函数.我尝试了很多不同的方法,似乎无法弄明白.任何帮助将不胜感激.

Error
EmployeeTest.java:13: cannot find symbol
symbol  : constructor Employee()
location: class Employee
    Employee x = new Employee();
                 ^
EmployeeTest.java:14: cannot find symbol
symbol  : constructor Employee()
location: class Employee
    Employee y = new Employee();

public class Employee
{
private double salaryValue; // variable that stores monthlySalary
private String firstName; // instance variable that stores first name
private String lastName; // variable that stores last name

 public Employee( String firstNameParameter , String lastNameParameter ,  double          salaryValueParameter )
{

    if ( salaryValueParameter < 0.0 ) // validate monthlySalary > 0.0
    salaryValue = 0.0; // if not salary is intitalized to default

    else 

      firstName = firstNameParameter;
      lastName = lastNameParameter;
      salaryValue = salaryValueParameter;
}  

 public class EmployeeTest 
{
public static void main( String[] args )
{   
String temp;
Double temp2;
Double temp3;

Employee x = new Employee();
Employee y = new Employee();

Answer 1

因为您添加了一个带有3个参数的构造函数,所以Employee该类不再具有默认构造函数 - 一个不带参数的构造函数.所以你不能这样做:

Employee x = new Employee();

并且您必须包含3个参数:

Employee x = new Employee("firstname", "lastname", 123.45);

如果要在Employee不提供任何参数的情况下实例化,则必须添加无参数构造函数:

public Employee() {
}

您可以在Java语言规范的8.8.9节中阅读有关默认构造函数的更多信息.