如何从文本文件中读取数据并将其添加到链表中

Question

我正在尝试制作一个程序来保存医院的患者名单。我正在尝试从文本文件中读取数据并将其添加到链表的第一个节点。

我对如何从文本文件中读取数据并将其添加到列表感到困惑。

这是我目前尝试过的我的病人 Class：

public class Patient implements Serializable {

private String name;
private String patientIDNumber;
private String address;
private int height;
private double weight;


protected LLNode<Patient> head;


public Patient(String n, String ID, String Ad, int h, double w)
{
    name = n;
    patientIDNumber = ID;
    address = Ad;
    height = h;
    weight = w;


}

public String get_name()
{
    return name;
}

public String get_patientIDNumber()
{
    return patientIDNumber;
}

public String get_address()
{
    return address;
}

public int get_height()
{
    return height;
}

public double get_weight()
{
    return weight;
}

public void set_name()
{
    this.name = name;
}

public void set_patientIDNumber()
{
    this.patientIDNumber = patientIDNumber;
}

public void set_address()
{
    this.address = address;
}

public void set_height()
{
    this.height = height;
}

public void set_weight()
{
    this.weight = weight;
}

}

我的链表class:

public class PatientList<T> implements ListInterface<T>{

protected int numOfElements;
protected LLNode<T> currentPos;
protected boolean found;
protected LLNode<T> location;
protected LLNode<T> previous;

protected LLNode<T> list;
protected LLNode<T> tail;

public PatientList()
{
    numOfElements = 0;
    list = null;
    currentPos = null;
}

public void add(T element)
{
    LLNode<T> newNode = new LLNode<T> (element);
    newNode.setLink(list);
    list = newNode;
    numOfElements++;
}

protected void find(T target)
{
    location = list;
    found = false;

    while(location != null)
    {
        if(location.getInfo().equals(target))
        {
            found = true;
            return;
        }
        else
        {
            previous = location;
            location = location.getLink();
        }
    }
}

public int size()
{
    return numOfElements;
}

public boolean contains(T element)
{
    find(element);
    return found;
}

public boolean remove(T element)
{
    find(element);
    if(found)
    {
        if(list == location)
            list = list.getLink();
        else
            previous.setLink(location.getLink());

        numOfElements++;
    }
    return found;
}
public T get(T element)
{
    find(element);
    if(found)
        return location.getInfo();
    else
        return null;
}

public String toString()
{
    LLNode currNode = list;
    String listString = "List:\n";
    while(currNode != null)
    {
        listString = listString + "  " + currNode.getInfo() + "\n";
        currNode = currNode.getLink();
    }
    return listString;
}
public void reset()
{
    currentPos = list;
}

public T getNext()
{
    T next = currentPos.getInfo();
    if (currentPos.getLink() == null)
        currentPos = list;
    else
        currentPos = currentPos.getLink();
    return next;
}

}

我的文本文件如下所示：

Random Name
1024 
Random Ln NY
70 
185
Joe Smith
1025
134 Nowhere Lane New York NY
80 
170

我一直在尝试这样读取数据：

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

public class PatientApplicationTester {
    public static void main(String[] args) throws ClassNotFoundException
    {
        PatientList<Patient> list = new PatientList<Patient>();
        try {
            File f = new File("Patients.txt");
            FileReader r = new FileReader(f);
            BufferedReader reader = new BufferedReader(r);

            String line = null;

            while((line = reader.readLine()) != null)  {
                System.out.println(line);

        }
        reader.close();
    } catch(IOException e) {
        e.printStackTrace();
    }

}

}

我知道这只是逐行读取然后打印出来，我真的很困惑我将如何读取数据然后将其作为 Patient 对象添加到链表中。如有任何帮助，我们将不胜感激。

Answer 1

在您的 Patient class 中添加一个构造函数，它将在您的主要方法中使用：

public Patient()
{

}

在您的 PatientApplicationTester class 的主要方法中将其替换为以下代码：

public static void main(String[] args) throws ClassNotFoundException
    {
        PatientList<Patient> list = new PatientList<Patient>();
        try {
            File f = new File("Patients.txt");
            FileReader r = new FileReader(f);
            BufferedReader reader = new BufferedReader(r);

            String line = null;
            Patient patient = new Patient(); // create Object use the constructor that I added.
            int i = 1; // this variable is used to know on which line the reader is on
            while((line = reader.readLine()) != null)  
            {
               if(line.trim().equals("")) // if the line is a new line then add the previous patient to the list and create a new patient, re initialize i = 0
               {
                    list.add(patient);
                    patient = new Patient();
                    i = 1;
               }
               else
               {
                    if(i == 1) // on first line of the file set the patients name
                    {
                        patient.set_name(line);
                    }
                    else if(i == 2)//on second line of the file set the patients ID Number
                    {
                        patient.set_patientIDNumber(line);
                    }
                    // add else if for other attributes on other lines
                    i++;
               }    
            }
             list.add(patient);

             reader.close();

        }catch(IOException e) {
            e.printStackTrace();
        }
    }

在 Patients.txt 文件中用如下新行分隔您的患者：

Random Name
1024 
Random Ln NY
70 
185

Joe Smith
1025
134 Nowhere Lane New York NY
80 
170

最后在你的 Patients Class 中 setter 方法是错误的你需要给它添加参数例如

public void set_name(String name)
{
    this.name = name;
}

如何从文本文件中读取数据并将其添加到链表中

How to read data from a textfile and add it to a linked list

java

io

linked-list