Java 员工、姓名、姓氏和ID

我刚刚开始，它真的很混乱，因为当我编写代码时，eclipse上没有红色警告，但是当我运行程序时，它不工作。 问题是:

编写一个显示员工ID和员工姓名的程序。使用两个类。第一个类包含employee数据和用于设置ID和名称的单独方法。另一个类为雇员创建对象，并使用这些对象调用set方法。创建多个员工并显示他们的数据

我的代码是：

public class Employee {
    String lastName = null; 
    String firstName = null; 
    double ID; 

    public Employee(String lastName, String firstName, double ID){
        this.lastName = lastName; 
        this.firstName = firstName; 
        this.ID = ID; 
    }

    public String empStat(){
        return "Last Name: " + lastName + "First Name: " + firstName + "ID" + ID; 
    }

}

及

它所做的只是显示

Employee@523ce3f Employee@71b98cbb Employee@4cc68351 Employee@7cd76237 Employee@523ce3f Employee@71b98cbb Employee@4cc68351 Employee@7cd76237 有人能告诉我为什么吗

变化

public String empStat()

到

查看

toString（）

是如何工作的（以及为什么会看到Employee@523ce3f)在

---

当您使用

System.out.println（nub1）时

隐式调用方法

nub1.toString（）

。

必须重写toString（）方法。每当对象需要返回对象的字符串时，都会调用该函数。默认情况下，您会收到'Employee@523ce3f'是对象的唯一内部表示形式（字符串形式）

仅仅创建一个返回字符串的方法并不能做到这一点

要覆盖toString（）方法更改，请执行以下操作：

公共字符串empStat（）

到

@凌驾 公共字符串toString（）

---

如果您试图打印对象，它将输出对象的哈希代码。打印对象调用对象类中的

toString（）

方法时，必须重写toString方法以获取对象的状态

public String toString()
{
return firstName+" "+lastName+" "+ ID;
}

List<Employee> list= new ArrayList<Employee>();
Employee o= new Employee("Will","Smith",1);
Employee o1= new Employee("Jason","Bourne",2);
list.add(o);
list.add(o1);
for (Employee x:list)
System.out.print(x);

重写<代码> toStase是最简单的方法，考虑一个列表：<代码> <代码>类型。打印列表现在将返回对象的当前字段值

public String toString()
{
return firstName+" "+lastName+" "+ ID;
}

List<Employee> list= new ArrayList<Employee>();
Employee o= new Employee("Will","Smith",1);
Employee o1= new Employee("Jason","Bourne",2);
list.add(o);
list.add(o1);
for (Employee x:list)
System.out.print(x);

---

您需要一个

toString

方法a

public String toString() {
    return lastName + " " + firstName + " " + Double.toString(ID);
}

总而言之：

class Employee {
    String lastName = null;
    String firstName = null;
    double ID;

    public Employee(String lastName, String firstName, double ID){
        this.lastName = lastName;
        this.firstName = firstName;
        this.ID = ID;
    }

    public String empStat(){
        return "Last Name: " + lastName + "First Name: " + firstName + "ID" + ID;
    }

    public String toString() {
        return lastName + " " + firstName + " " + Double.toString(ID);
    }

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

        Employee nub1 = new Employee ("Griffin", "Peter", 000001);
        System.out.println(nub1);
        Employee nub2 = new Employee ("Griffin", "Lois", 000002);
        System.out.println(nub2);
        Employee nub3 = new Employee ("Griffin", "ST", 000003);
        System.out.println(nub3);
        Employee nub4 = new Employee ("Griffin", "Brian", 000004);
        System.out.println(nub4);
    }
}

结果如下：

Griffin Peter 1.0
Griffin Lois 2.0
Griffin ST 3.0 
Griffin Brian 4.0

---

请注意：不要养成零填充数字的习惯

000010

不是您认为的数字。另见

class Employee {
    String lastName = null;
    String firstName = null;
    double ID;

    public Employee(String lastName, String firstName, double ID){
        this.lastName = lastName;
        this.firstName = firstName;
        this.ID = ID;
    }

    public String empStat(){
        return "Last Name: " + lastName + "First Name: " + firstName + "ID" + ID;
    }

    public String toString() {
        return lastName + " " + firstName + " " + Double.toString(ID);
    }

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

        Employee nub1 = new Employee ("Griffin", "Peter", 000001);
        System.out.println(nub1);
        Employee nub2 = new Employee ("Griffin", "Lois", 000002);
        System.out.println(nub2);
        Employee nub3 = new Employee ("Griffin", "ST", 000003);
        System.out.println(nub3);
        Employee nub4 = new Employee ("Griffin", "Brian", 000004);
        System.out.println(nub4);
    }
}

Griffin Peter 1.0
Griffin Lois 2.0
Griffin ST 3.0 
Griffin Brian 4.0