Question

我正在我的项目中工作，涉及一家诊所，我的班级是预约，我必须让用户输入日期，时间，科，医生姓名，患者姓名。并存储一个ArrayList 我写了代码，但是当我运行项目时，没有输出，我也不知道为什么：（

package appointments;
import java.util.Scanner;
import java.util.ArrayList;

public class Appointment {


  public static void main(String[] args) {

    ArrayList<Object> appointments = new ArrayList<>();
    Scanner input = new Scanner (System.in);
    System.out.println("enter day, time, section , doctor , you name in order to book appointment : ");

    appointment xx = new appointment();

    for (int i=0; i<5; ++i)
    xx.setAppDay(input.nextLine());
    xx.setAppTime(input.nextLine());
    xx.setAppSection(input.nextLine());
    xx.setAppDoctor(input.nextLine());
    xx.setAppPatient(input.nextLine());

    appointments.add(xx);
    System.out.println(appointments);

}


public static class appointment {
    public String appDay;
    public String appTime;
    public String appSection;
    public String appDoctor;
    public String appPatient;


    public appointment(String appDay, String appTime, String appSection, String appDoctor, String appPatient) {
        this.appDay = appDay;
        this.appTime = appTime;
        this.appSection = appSection;
        this.appDoctor = appDoctor;
        this.appPatient = appPatient;

    }

    public appointment() {

    }

    public void setAppDay(String appDay) {
        this.appDay = appDay;
    }

    public void setAppTime(String appTime) {
        this.appTime = appTime;
    }

    public void setAppSection(String appSection) {
        this.appSection = appSection;
    }

    public void setAppDoctor(String appDoctor) {
        this.appDoctor = appDoctor;
    }

    public void setAppPatient(String appPatient) {
        this.appPatient = appPatient;
    }

    public String getAppDay() {
        return appDay;
    }

    public String getAppTime() {
        return appTime;
    }

    public String getAppSection() {
        return appSection;
    }

    public String getAppDoctor() {
        return appDoctor;
    }

    public String getAppPatient() {
        return appPatient;
    }

  }

}

Answer 1

您的循环没有花括号，并且您仅实例化一个appointment。您想要类似的东西，

for (int i = 0; i < 5; ++i) {
    appointment xx = new appointment();
    xx.setAppDay(input.nextLine());
    xx.setAppTime(input.nextLine());
    xx.setAppSection(input.nextLine());
    xx.setAppDoctor(input.nextLine());
    xx.setAppPatient(input.nextLine());

    appointments.add(xx);
}

然后，您需要覆盖toString()中的appointment。

Answer 2

当前将同一约会对象添加到列表中，因此列表中将只有一个条目。

因此将对象的创建和添加移动到列表中，并在for循环内设置约会字段。请正确添加大括号，因为当前仅 xx.setAppDay（input.nextLine（））是for循环的一部分。

约会也不应该是静态类，需要创建多个对象。

Answer 3

为此，您需要实现toString（）方法。然后像这样打印。

public String toString(){
    return this.appDay; // return the output you want, so build a String using your attributes
}

System.out.println(Arrays.toString(appointments));

编辑：按照Elliott Frisch所说的做。

如何将对象存储在ArrayList中并进行打印？

3 个答案: