java将2D数组传递给构造函数

Question

你能告诉我如何将2D数组传递给构造函数吗。我已经用值传递了数组，但我得到了错误的答案。在这里与我分享我的代码

    package payroll;
    import java.util.Scanner; 
    import javax.swing.*;

    class Payroll
    {
     private String empID;   
     private String empName;
     private int numOfHours;
     private double hourlyRate;
     private double totalPay;

     public Payroll(){}

     public Payroll(Object[][]emp, int scale)
     {
      for(int k=0;k<emp.length;k++)
      {
         this.empID = emp[k][l].toString();
         this.empName = emp[k][l].toString();
         this.numOfHours = Integer.parseInt(emp[k][l].toString()); 
         this.hourlyRate = Integer.parseInt(emp[k][l].toString());
       }
  }
 }

     public String getID()
     {
     return empID;
     }
     public String getName()
     {
     return empName;
     }
     public int getNumOfHours()
     {
     return numOfHours;
     }
     public double getHourlyRate()
     {
     return hourlyRate;
     }

     public double gettoTotalPay()
     {
     return numOfHours * hourlyRate;
     }

    }


    class Employer{
             public static void main(String [] args)
      {
            String empId; 
            String empName;
            String numOfHrs;
            String hourlyRate;
            Payroll emp1 = new Payroll();
            Object [][]emp = new Object[1][1];


           Scanner sc = new Scanner(System.in);

    for(int i=0;i<emp.length;i++)
      {   // start for loop
         for(int j=0;j<emp[0].length;j++)
            {  
             emp[i][j]= JOptionPane.showInputDialog(null,"Enter Employer ID");
               if ( (emp[i][j].equals(""))) 
                 {
                   JOptionPane.showMessageDialog( null,"Employee ID Not Correct");
             emp[i][j]= JOptionPane.showInputDialog(null,"Enter Employer ID");       
                }
            emp[i][j] = JOptionPane.showInputDialog(null,"Enter Employer Name");
            if(emp[i][j] == null )
                    {
                JOptionPane.showMessageDialog(null,"Employee Name Cannot Be Empty");
            emp[i][j] = JOptionPane.showInputDialog(null,"Enter Employer Name");
                    }
            emp[i][j] =  JOptionPane.showInputDialog(null,"Enter Number of Hours Worked on");
            if(emp[i][j] == null )           
            {
            JOptionPane.showMessageDialog(null,"Number of Hour Cannot be empty or more than 8");
            emp[i][j] =  Integer.parseInt(JOptionPane.showInputDialog(null,"Enter Number of Hours Worked on"));
            }
            emp[i][j] = JOptionPane.showInputDialog(null,"Enter Hourly Rate ");             
            if(emp[i][j] == null)
                {
                    JOptionPane.showMessageDialog(null,"Number of Hourly Rate Cannot be empty or Minus Value");
                hourlyRate = JOptionPane.showInputDialog(null,"Enter Hourly Rate ");                

                    } 
         emp1 = new Payroll(emp,6 ); // this is the 2D array pass to Payroll Class
                   }//end inner for loop 
       }//end for loop          

      System.out.println("Employee Id:" +emp1.getID() );
      System.out.println("Employee Name:" +emp1.getName() );
      System.out.println("Employee Hours:" +emp1.getNumOfHours());
      System.out.println("Employee Total Payment:" +emp1.gettoTotalPay() );

      }
}

如果我插入

employe id:1
emaployee name : asd
employee num of hrs:1
employee hourly rate :100

但答案是

Employee Id:1
Employee Name:1
Employee Hours:1
Employee Total Payment:1.0

需要建议吗

Answer 1

只需移除内部for循环并添加

++j;

三次在雇主班

现在它运行良好。正如你在评论中提到的那样，你之所以得到nullPointerException，是因为你不打算进入下一列，而是停留在第0列，因此你必须增加j

    import java.util.Scanner; 
    import javax.swing.*;
    class Employer{
             public static void main(String [] args)
      {
            String empId; 
            String empName;
            String numOfHrs;
            String hourlyRate;
            Payroll emp1 = new Payroll();
            Object [][]emp = new Object[3][4];
           Scanner sc = new Scanner(System.in);

    for(int i=0;i<emp.length;i++)
      {   // start for loop
            int j=0;  
             emp[i][j]= JOptionPane.showInputDialog(null,"Enter Employer ID");
               if ( (emp[i][j].equals(""))) 
                 {
                   JOptionPane.showMessageDialog( null,"Employee ID Not Correct");
             emp[i][j]= JOptionPane.showInputDialog(null,"Enter Employer ID");       
                }
                ++j;
            emp[i][j] = JOptionPane.showInputDialog(null,"Enter Employer Name");
            if(emp[i][j] == null )
                    {
                JOptionPane.showMessageDialog(null,"Employee Name Cannot Be Empty");
            emp[i][j] = JOptionPane.showInputDialog(null,"Enter Employer Name");
                    }
                ++j;    
            emp[i][j] =  JOptionPane.showInputDialog(null,"Enter Number of Hours Worked on");
            if(emp[i][j] == null )           
            {
            JOptionPane.showMessageDialog(null,"Number of Hour Cannot be empty or more than 8");
            emp[i][j] =  Integer.parseInt(JOptionPane.showInputDialog(null,"Enter Number of Hours Worked on"));
            }
                ++j;
            emp[i][j] = JOptionPane.showInputDialog(null,"Enter Hourly Rate ");             
            if(emp[i][j] == null)
                {
                    JOptionPane.showMessageDialog(null,"Number of Hourly Rate Cannot be empty or Minus Value");
                hourlyRate = JOptionPane.showInputDialog(null,"Enter Hourly Rate ");                

                } 
         emp1 = new Payroll(emp,i ); // this is the 2D array pass to Payroll Class
                   //end inner for loop 
       }//end for loop          
      for(int i=0;i<emp.length;i++)
      {
       System.out.println("Employee Id:" +emp1.getID() );
       System.out.println("Employee Name:" +emp1.getName() );
       System.out.println("Employee Hours:" +emp1.getNumOfHours());
       System.out.println("Employee Total Payment:" +emp1.gettoTotalPay() );
      }

      }
}
    class Payroll
    {
     private String empID;   
     private String empName;
     private int numOfHours;
     private double hourlyRate;
     private double totalPay;

     public Payroll(){}

     public Payroll(Object[][]emp, int scale)
     {

      for(int k=0;k<=scale;k++)
      {
          int l=0;
         this.empID = emp[k][l++].toString();
         this.empName = emp[k][l++].toString();
         this.numOfHours = Integer.parseInt(emp[k][l++].toString()); 
         this.hourlyRate = Float.parseFloat(emp[k][l++].toString());
       }
  }


     public String getID()
     {
     return empID;
     }
     public String getName()
     {
     return empName;
     }
     public int getNumOfHours()
     {
     return numOfHours;
     }
     public double getHourlyRate()
     {
     return hourlyRate;
     }

     public double gettoTotalPay()
     {
     return numOfHours * hourlyRate;
     }

    }

Answer 2

public Payroll(Object[][]emp, int scale)
 {
  for(int k=0;k<emp.length;k++)
  {
     this.empID = emp[k][l].toString();
     this.empName = emp[k][l].toString();
     this.numOfHours = Integer.parseInt(emp[k][l].toString()); 
     this.hourlyRate = Integer.parseInt(emp[k][l].toString());
   }

我认为你没有在循环中增加Valrable l。你能用l++替换它吗。试着让我知道