java - 在文件中写入和读取对象

Question

我想读取一个对象并将其写入文件。这是我的尝试:

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.ArrayList;

public class SaveOpen implements Serializable 
{
    private static String fileName;
    private ArrayList<Person> list = new ArrayList<Person>();

    public SaveOpen() {
        fileName = "file.txt";
    }
    //Reader
    public static Object deserialize() throws IOException,
    ClassNotFoundException {
        FileInputStream fis = new FileInputStream(fileName);
        BufferedInputStream bis = new BufferedInputStream(fis);
        ObjectInputStream ois = new ObjectInputStream(bis);
        Object obj = ois.readObject();
        ois.close();
        return obj; 
    }
    //Writer
    public static void serialize(Object obj)
            throws IOException {
        FileOutputStream fos = new FileOutputStream(fileName);
        BufferedOutputStream bos = new BufferedOutputStream(fos);
        ObjectOutputStream oos = new ObjectOutputStream(bos);
        oos.writeObject(obj);
        oos.close();
    }
    public void setFileName(String fileName) {
        this.fileName = fileName;
    }
    public ArrayList<Person> getListPersons() {
        return list;
    }

}

但是，我不知道这是否是正确的方法，也不知道如何在类中实现它。该对象是 Person，我想从文件中保存和读取该对象。是否应该对 .txt 文件执行？有谁可以澄清一下吗？谢谢!

Answer 1

如果您希望该文件可供人类阅读，我建议将其另存为 xml。

示例:

• 对象类别

  import java.io.Serializable;
  
  public class Person implements Serializable
  {
       private String username;
       private int    id;
  
       public String UserName() { return username; }
       public void setUserName(String str) { username = str;} 
  
       public int ID() { return id; }
       public void setID(int ID) { id = ID; }    
  }
  

-序列化器/解串器

import Settings.Person;
import java.beans.XMLDecoder;
import java.beans.XMLEncoder;
import java.io.ByteArrayInputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;

public class XmlSerializer 
{
    //File path to serialize to and deserialize from
    private static final String SERIALIZED_FILE_NAME = "yourSavePath.xml";
    //Insert person object and save as xml file to chosen filepath
    public static void Serialize(Person person)
    {
        try
        {
            FileOutputStream    os = new FileOutputStream(SERIALIZED_FILE_NAME);
            XMLEncoder          encoder = new XMLEncoder(os);
                                encoder.writeObject(person);
                                encoder.close();
        }
        catch(FileNotFoundException ex)
        {
            System.out.println(ex.getMessage());
        }
    }
    //Deserialize xml file into person object
    public static Person Deserialize()
    {
        try
        {
            FileInputStream os = new FileInputStream(SERIALIZED_FILE_NAME);
            XMLDecoder decoder = new XMLDecoder(os);
            Person p = (Person)decoder.readObject();
            decoder.close();
            return p;
        }
        catch(FileNotFoundException ex)
        {
            System.out.println(ex.getMessage());
        }
        return null;
    }
  }