如何编写toString（）方法[重复]

Question

如何编写一个toString（）方法，为三名员工打印名称和computePay，小数点后两位？在我添加StringBuilder之前，该程序正在工作（将名称和周支付打印到命令行）。感谢任何帮助。

import javax.swing.JOptionPane;

public class TestPayroll {

        public static void main(String[] args) {

                Payroll employee1 = new Payroll("Tiny Tim", 100.25, 40);
                Payroll employee2 = new Payroll("Brad Pitt", 150.50, 10);
                Payroll employee3 = new Payroll("Madonna", 124.24, 20);

        StringBuilder sb = new StringBuilder();

        String toDisplay=sb.toString();        
        sb.append(String.format("\n", employee1.getName(), employee1.getComputePay()));
        sb.append(String.format("\n", employee2.getName(), employee2.getComputePay()));


        JOptionPane.showMessageDialog(null, sb.toString(), toDisplay, JOptionPane.INFORMATION_MESSAGE);
        }                       
}

public class Payroll {

    public static void main(String[] args) {
                }

                private String name;
                private double payRate;
                private double hrsWorked;
                private double computePay;

                //default constructor
                public Payroll() {
                        this.name = name;
                        this.payRate = payRate;
                        this.hrsWorked = hrsWorked;
                        this.computePay = computePay;
                }

                //Payroll constructor
                public Payroll(String name, double payRate, double hrsWorked) {
                        this.name = name;
                        this.payRate = payRate;
                        this.hrsWorked = hrsWorked;
                }

                //return name
                public String getName() {
                        return name;
                }

                //set name
                public void setName(String name) {
                        this.name = name;
                }

                //return pay rate
                public double getPayRate() {
                        return payRate;
                }

                //set pay rate
                public void setPayRate(double payRate) {
                        this.payRate = payRate;
                }

                //return hours worked for the week
                public double getHrsWorked() {
                        return hrsWorked;
                }

                //set hours worked for the week
                public void setHrsWorked(double hrsWorked) {
                        this.hrsWorked = hrsWorked;
                }

                //find week's pay
                public double getComputePay() {
                        double computePay = payRate * hrsWorked;
            return computePay;
                }      

}

Answer 1

这会有帮助

    @Override
    public String toString(){
        Formatter fmt = new Formatter();
        fmt.format("%.2f", computePay);
        return "Name : "+name+"\n"+"ComputePay : "+fmt.toString();
    }

当然，您需要导入java。util。格式化程序。

Answer 2

您可以使用Apache ToStringBuilder类。这是一个来自留档的示例：

 public class Person {
   String name;
   int age;
   boolean smoker;

   ...

   public String toString() {
     return new ToStringBuilder(this).
       append("name", name).
       append("age", age).
       append("smoker", smoker).
       toString();
   }
 }

Answer 3

要格式化十进制数字，可以使用java。文本DecimalFormat，在类级别将其定义为类成员，这样它就可以为工资单的所有对象共享其行为，正如@Multithreader在注释中提到的，这将是您的toString（）方法：

 private static DecimalFormat df = new DecimalFormat("#.##");
 //......
    @Override
    public String toString(){
      return "Name: "+getName()+
             "\nCompute Pay: "+df.format(getComputePay())+"\n";
    }

像这样调用方法：

System.out.println(employee1.toString());

我更喜欢使用java。util。列出大量代码：

public static void main(String[] args) {
    List <Payroll> employes = new ArrayList<>();

    employes.add( new Payroll("Tiny Tim", 100.2534, 40.87876));
    employes.add( new Payroll("Brad Pitt", 150.50, 10));
    employes.add( new Payroll("Madonna", 124.24, 20));

    for(Payroll p :employes){
    System.out.println(p.toString()+"\n");
    }
}