将患者信息存储到文本文件中并在之后加载

Question

我们接到了编写一个简单的医院管理系统的任务。用户能够输入患者信息，例如姓名、性别、出生日期和疾病。
数据存储在 ArrayList 中并保存到文本文件中。

现在我的问题是：我需要显示输入系统的所有患者。
但是我无法以正确的方式取回数据并将其显示在控制台中 window。
输出应该类似于：患者姓名、性别、疾病、出生日期。

这是我的代码。这不是全部代码，只是其中的一部分。
这是主要的class..

import java.io.*;
import java.util.*;

public class Main {

public static void main (String args []) {

    int choice = 0;

    List<Patient> PatientList = new ArrayList<Patient>();       
    Patient patient = new Patient();        
    List<Doctor> DoctorList = new ArrayList<Doctor>();
    Doctor doctor = new Doctor();

    Scanner readInput = new Scanner(System.in);
    Scanner readChoice = new Scanner(System.in);        


    do {
            System.out.println("Press 1 to enter a new patient \nPress 2 to enter a new doctor \nPress 3 to show all patients \nPress 4 to show all doctors \nPress 0 to quit.");   
            choice = readChoice.nextInt();

        switch (choice) {

            //case 0: 

            case 1: System.out.println("Please enter the name of the new patient: ");
                    patient.setPatientName(readInput.nextLine());


                    System.out.println("Please enter the gender of the new patient: ");
                    patient.setPatientGender(readInput.nextLine());

                    System.out.println("Please enter the disease of the new patient: ");
                    patient.setDisease(readInput.nextLine());       

                    System.out.println("Please enter the age of the new patient: ");
                    patient.setPatientDateOfBirth(readInput.nextLine());

                    PatientList.add(patient);

            try {
                FileOutputStream fos = new FileOutputStream("patients.tmp");
                ObjectOutputStream oos = new ObjectOutputStream(fos);
                oos.writeObject(PatientList);
                oos.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

                    break;      

/////////////////////////////////////////////////////////////////   
//case 2 is not relevant to my question therefore I did not put it in here

            case 3: if(PatientList.size() == 0) {

                        System.out.println("\nNo patients were found...\nReturning to main menu...\n");     

                    } 

                    else {  


                            try {
                                FileInputStream fis = new FileInputStream("patients.tmp");
                                ObjectInputStream ois = new ObjectInputStream(fis);
                                PatientList =(ArrayList<Patient>) ois.readObject();
                                ois.close();
                                fis.close();
                            } catch (FileNotFoundException e) {
                                // TODO Auto-generated catch block
                                e.printStackTrace();
                            } catch (ClassNotFoundException e) {
                                // TODO Auto-generated catch block
                                e.printStackTrace();
                            } catch (IOException e) {
                                // TODO Auto-generated catch block
                                e.printStackTrace();
                            }


                        for (int i = 0; i < PatientList.size(); i++) {                              

                            System.out.println(PatientList.get(i).getPatientName()+", "+PatientList.get(i).getPatientDateOfBirth()+", "
                            +PatientList.get(i).getPatientGender()+", "+PatientList.get(i).getDisease());                       

                        }

                    }                       
                    break;

还有患者class

import java.io.Serializable;


public class Patient implements Serializable {

private String patientName;
private String patientGender;
private String disease; 
private String patientDateOfBirth;

public Patient (String patientName, String patientGender, String disease, String patientDateOfBirth) {
    this.patientName = patientName;
    this.patientGender = patientGender;     
    this.disease = disease;
    this.patientDateOfBirth = patientDateOfBirth;
}

public Patient() {

}

public String getPatientName () {

    return patientName;

}

public void setPatientName (String patientName) {

    this.patientName = patientName;

}

public String getPatientGender () {

    return patientGender;

}

public void setPatientGender (String patientGender) {

    this.patientGender = patientGender;

}

public String getDisease () {

    return disease;

}

public void setDisease (String disease) {

    this.disease = disease;

}

public String getPatientDateOfBirth () {

    return patientDateOfBirth;

}

public void setPatientDateOfBirth (String patientDateOfBirth) {

    this.patientDateOfBirth = patientDateOfBirth;

}
}

我猜主要有一些错误 class （情况 3），但我自己无法解决。

非常感谢您的帮助！

Answer 1

它从不在第一次启动时从磁盘加载数据的原因是因为案例 3 中的第一个 if 语句检查 PatientList.size 是否为空，如果是则不从磁盘加载数据（ else 语句仅在列表中有内容时运行）

case 3: 
    //this if statment is checking if PatientList.size() is 0 or in other words check if it is empty
    if(PatientList.size() == 0) 
    {
        System.out.println("\nNo patients were found...\nReturning to main menu...\n");     
    }
    //this else code block will only run if the above if statment is false
    else 
    {  
        try 
        {
            //load data from the hard drive
        } catch (FileNotFoundException e) {
        } catch (ClassNotFoundException e) {
        } catch (IOException e) {
        }
    }                       
break;

要解决这个问题，您可能需要检查 PatientList.isEmpty() 是否存在，如果存在，则尝试从磁盘加载数据，如果没有数据，则打印出未找到的记录。

case 3: 
    if(PatientList.isEmpty()) 
    {
        try 
        {
            //load data from the hard drive
        } catch (FileNotFoundException e) {
        } catch (ClassNotFoundException e) {
        } catch (IOException e) {
        }

        //populate PatientList if data was loaded from disk here

        //if PatientList is still empty then print out no patients found
        if(PatientList.isEmpty())
        {
            System.out.println("\nNo patients were found...\nReturning to main menu...\n");
        }           
    }

break;

将患者信息存储到文本文件中并在之后加载

Store patient information into text file and load it afterwards

java

arrays

arraylist

text-files